Wild bees in the Hoeksche Waard

Wilson Westdijk C.S.G. Willem van Oranje

Text: Wilson Westdijk

Applicant: C.S.G. Willem van Oranje

Contact person applicant: Bart Lubbers

Photos front page Upper: Typical landscape of the Hoeksche Waard - Rotary Hoeksche Waard Down left: Andrena rosae - Gert Huijzers ​ ​ Down right: Bombus muscorum - Gert Huijzers ​ ​

Table of contents

Summary 3

Preface 3

Introduction 4 Research question 4 Hypothesis 4 Method 5 Field study 5 Literature study 5

Bee studies in the Hoeksche Waard 9

Habitats in the Hoeksche Waard 11 Origin of the Hoeksche Waard 11 Landscape and bees 12

Bees in the Hoeksche Waard 17 Recorded bee species in the Hoeksche Waard 17 Possible species in the Hoeksche Waard 22

Comparison 99 Compared to Land van Wijk en Wouden 100

Species of priority 101 Species of priority in the Hoeksche Waard 102

Threats 106

Recommendations 108

Conclusion 109

Discussion 109

Literature 111

Sources photos 112

Attachment 1: Logbook 112

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Summary

At this moment 98 bee species have been recorded in the Hoeksche Waard. 14 of these species are on the red list. 39 species, that have not been recorded yet, are likely to occur in the Hoeksche Waard. This results in 137 species, which is 41% of all species that occur in the Netherlands. The species of priority are: Andrena rosae, A. labialis, A. wilkella, Bombus ​ jonellus, B. muscorum and B. veteranus. Potential species of priority are: Andrena pilipes, A. ​ ​ ​ gravida Bombus ruderarius B. rupestris and Nomada bifasciata. ​ ​ Threats to bees are: scaling up in agriculture, eutrophication, reduction of flowers, pesticides and competition with honey bees. Recommended actions are firstly more research and second management actions aimed to increase the amount of flowers.

Preface

My interest in bees started with a lack of butterflies. It was a sunny day in early spring. I was making a little walk and hoping for the first butterfly. Instead of a butterfly I say a huge bumblebee. It turned out to be a queen Bombus lapidarius. I made the same walk the next ​ ​ day and found a queen Bombus pascuorum and so my interest in bees started. I soon ​ realised there was few information about bees in the Hoeksche Waard, which meant there was still a lot to discover! This resulted in this profile paper. First of all I want to thank Henk Bunjes from HWL, for helping with finding information about the Hoeksche Waard. As well as Menno Reemer and John Smit from EIS kenniscentrum, for providing information about bee studies in the Hoeksche Waard. Furthermore I want to thank Gert Huijzers, Sylvia Coolen and Jaco Visser for providing photos.

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Introduction

Bees are becoming more and more popular. More people are interested in them and care about them. And bees need to be cared for, since their populations are under pressure. More than half of the species in the Netherlands is under threat. This is getting more and more media coverage. However finding information about bees in the Hoeksche Waard is quite hard, since there is very little. Therefore the aim of this report is to give more clearance in which bee species have been recorded and which species could be recorded in the future. In addition species of priority have been selected and possible actions that could be taken to help bees are given.

Research question

How many bee species occur in the Hoeksche Waard compared to the whole of the Netherlands? Subquestions: ● What research has been done already concerning bees in the Hoeksche Waard? ● Which habitats are present in the Hoeksche Waard? ● Which bee species have been recorded in the Hoeksche Waard. ● Which bee species could occur in the Hoeksche waard? ● What are the species of priority for the Hoeksche Waard? ● What is threatening bees? ● What could be done to help bees?

Hypothesis

Few bee species and mostly common species occur in the Hoeksche Waard. I expect about 40% of the known bee species in the Netherlands could occur in the Hoeksche Waard, because ea clay areas are generally poor in biodiversity and most of the Hoeksche Waard is used for intensive agriculture. This results in a landscape poor in flowers and nesting places for bees in which more specialized bees can not survive (Peeters et al, 2012; HWL, 1999).

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Method

The method can be divided into 2 parts: a field study and a literature study. Most time was spent on the literature study, as I started this with this profile paper in September. At this time the flight period of many bee species was already over.

Field study

I visited most areas in the Hoeksche Waard, although bees were not always necessarily the reason for the visit. I made 163 observations divided over 29 species. Both the number of observations and the number of species will increase in the next year, as I am planning to spend more time looking for bees over the coming years. I used the book “Veldgids Bijen voor Nederland en Vlaanderen” to determine species. The observations can be found on www.hwl.waarneming.nl. I started determining bees by ​ ​ photographing them, later by picking them up by hand and eventually with a butterfly net. I spent 5 days searching specifically for Andrena rosae. This resulted in 68 specimen ​ ​ recorded in 7 areas.

Literature study

In order to be able to carry out more aimed searches for species, I made a list of which species could occur in the Hoeksche Waard. To determine which species could occur in the Hoeksche Waard I used a model based on points. Points were awarded if the correct habitat, flowers visited for pollen or nectar, nesting places or the correct host species for cleptoparasitic bee species were present. Bees use elements in their habitat to orientate or to demarcate their territory. Bees need pollen to feed their young and nectar to survive themselves, so the correct flowers are essential for bees to occur in an area. Flower resources are more important but nesting availability also needs to be considered. For cleptoparasitic bees flower resources are less important, but the presence of host species is the driving factor behind their distribution (Torné-Noguera et al, 2014; Peeters et al, 2012). Points will also be rewarded or subducted considering the known distribution, e.g. a bee species only occurring in the south of Limburg is not likely to occur in the Hoeksche Waard. I used three models, one of polylectic bees, one for oligolectic and monolectic bees and one for cleptoparasitic bees.

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Polylectic bees Polylectic bees collect pollen and nectar from different unrelated plant species, making them less dependent on specific flowers. Therefore all factors are of even importance and are equal in the amount of points to be divided. Figure 1.0: Model for polylectic species

Factor points

Habitat

Not present 0

Present 1

Common 2

Flowers visited for pollen and nectar

Not present 0

Present 1

Common 2

Nesting places

Not present 0

Present 1

Common 2

Distribution pattern

Not likely -1

Possible 0

Likely 1

Figure 1.1: Likelihood of occurrence in the Hoeksche Waard for polylectic species

Result points

Very likely 7

Possible 5-6

Not likely 4

Very unlikely 0-3

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Oligolectic and monolectic bees Oligolectic bees collect pollen from one family of plants and monolectic bees from one single plant species. This makes them highly dependable on those plants and therefore more points are awarded if those plants are present than in the model for polylectic bees. Figure 2.0: Model for oligelectic and monogelectic species.

Factor points

Habitat

Not present 0

Present 1

Common 2

Flowers visited for pollen

Not present Not possible

Present 2

Common 4

Nesting places

Not present 0

Present 1

Common 2

Distribution pattern

Not likely -1

Possible 0

Likely 1

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Figure 2.1: Likelihood of occurrence in the Hoeksche Waard for oligelectic and monogelectic species

Result points

Very likely 9

Possible 6-8

Not likely 4-5

Very unlikely 0-3

Cleptoparasitic bees Cleptoparasitic bees lay their eggs in the nest of other bees. They are generally dependent on one or a few species to lay their eggs. Therefore it is very important these species are present, because without the host species the cleptoparasitic bees can not survive. For this reason the most points in this model are awarded for the host species and less for habitat and flowers visited for nectar. Figure 3.0: Model for cleptoparasitic species

Factor points

Habitat

Not present 0

Present 1

Common 2

Flowers visited for nectar

Not present 0

Present 1

Host species

Not present Not possible

Present 3

Distribution pattern

Not likely -1

Possible 0

Likely 1

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Figure 3.1: Likelihood of occurrence in the Hoeksche Waard for cleptoparasitic species

Result points

Very likely 7

Possible 5-6

Not likely 4

Very unlikely 0-3

Bee studies in the Hoeksche Waard

Bees are interesting organism to study, however difficult as well. Their behavior is what makes them interesting. Their ability to pollinate plants and create honey made them interesting to menkind. Although there is only one species that produces honey. All other species have different ways of living (Peeters et al, 2012). What makes bees so difficult to study are the facts that there are small or very similar to other species. In some cases microscopes are needed to see details of the jaws or the genitals before a determination can be made (Falk, 2015). In contrary to the well-known species groups like birds, mammals and plants, there has not been any intensive bee monitoring in the Hoeksche Waard. There have been a few studies, but no systematic research has taken place. In this project I will use observations from the follow sources (Reemer, Bunjes): ● “De Moshommel Bombus Muscorum in Zuid-Holland” Roos, M. & Reemer, M. 2009 ● “De bijenfauna van Zuid-Holland: Trends, prioritaire soorten en belangrijke gebieden” Reemer M. 2017 ● “Effecten van agrarisch natuurbeheer in de Hoeksche Waard op de diversiteit en abundantie van bloembezoekende insecten, in het bijzonder bestuivers” Zeegers, T. 2017 ● www.waarneming.nl ● “De Nederlandse bijen” by Theo Peeters e.a. 2012

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“De Moshommel Bombus Muscorum in Zuid-Holland” Roos, M. & Reemer, M. 2009 The report of a research on Bombus Muscorum. B. Muscorum is a rare species that has disappeared from large parts of the Netherlands. It is still present in some areas in the delta. One of those areas is Tiengemeten, which is visited three times during this research. The report includes a list of species found on Tiengemeten and the other areas in which B. Muscorum occurs, which I will use.

“De bijenfauna van Zuid-Holland: Trends, prioritaire soorten en belangrijke gebieden” Reemer M. 2017 This report summarizes everything known of wild bees in Zuid-Holland. This report includes a list of species known from Zuid-Holland, which species are threatened, for which species Zuid-Holland has a national responsibility, which are the species of priority, the most important areas for bees in Zuid-Holland and which types of management are the most important for bees in Zuid-Holland.

“Effecten van agrarisch natuurbeheer in de Hoeksche Waard op de diversiteit en abundantie van bloembezoekende insecten, in het bijzonder bestuivers” Zeegers, T. 2017 This is a report on the effect of agricultural naturemangement on the diversity and abundance of flower visiting insects and in special pollinators. This report was carried out in the Hoeksche Waard. During this research 44 species of bees were found. www.waarneming.nl A website to save observations online by used by professionals and amateurs. In the species group Hymenoptera there are over 2600 observations divided over 147 species. This include my own 162 observations divided over 29 species. The Hymenoptera group includes not only bees, but also wasps and ants. There are 92 bee species recorded on this site. In contrary to the other sources the observations on this site are not only gathered by professionals, but also by amateurs. Therefore the reliability of some of these observations needs to be questioned in some cases.

“De Nederlandse bijen” by Theo Peeters e.a. 2012 This book was created to make all information and data about bees easier to reach. This book includes information about the habitats of bees and their way of life, but also a species account including distribution maps for every species.

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Habitats in the Hoeksche Waard

Origin of the Hoeksche Waard

The Hoeksche Waard is an island in the province Zuid-Holland, situated just south of Rotterdam. The island is not natural, but made by man. At the end of the last ice age, 15,000 - 10,000 years ago, the sea level rose 60 cm per century. The coast of western Europe developed as it is now. The west of the Netherlands was during the ice age still an area with an extensive layer of sand. At the end of the ice age this changed into a river area with large estuaries, known as the Rijn-/Maas-system. On top of the sand layer sedimentation took place and a layer of 20 metres of clay, sand and peat was formed. The Binnenbedijkte Maas can be seen as a remnant of this ancient Rijn-/Maas-system. At the end of the last ice age a gradual improvement in climate started. This lead to a whole new flora and fauna in the Hoeksche Waard. The sea level continued to rise, but on a lower rate than before. The sea continued to expand to the east and the coast line was approximately 10 kilometres from the most western point of the Hoeksche Waard. The western part of the Hoeksche Waard was mostly influenced by the sea, the eastern part however more by the rivers. As a result of these different water flows a dynamic system of smaller streams arose. Sedimentation not only took place in or near the smaller streams, but the rivers regularly deposed large strips of clay. In this landscape of mud and clay, a peat landscape was formed. When the sea level hardly rose anymore, a more or less closed row of dunes formed at the coast. This lead to a change in the landscape of the Hoeksche Waard around 4000 BC. The Rijn and Maas became deeper as a result of erosion. This resulted in a better drainage of the area. From 3800 to 2300 BC there were large deposits of coarse sand. This lead to hydrosere in the system of creeks running through the Hoeksche Waard. These hydrosere creeks were higher than the surrounding area. This formed the perfect base for human habitation. Around 200-100 BC for the first time in two thousand years an enormous amount of clay was deposited by the Maas and Rijn. Especially around the Binnenmaas was a large deposition,

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approximately six kilometres wide and a few decimetre high. The peat landscape became covered in clay. This lead again to a stable landscape, until the eleventh century. In this century there were more problems with water. The consequences were not severe, until the half of the twelfth century. In this period many floods occurred. This lead to large migration out of the Hoeksche Waard. The clay deposits of the fifteenth and mainly the sixteenth century were an equalizing factor. The height differences were smoothed, leading to the plain landscape of the Hoeksche Waard as we know it nowadays. Between 1539 and 1653 large polders were created in the Hoeksche Waard. Men was now in charge of the landscape and the natural landscape formation was from now subordinate (HWL, 2006).

Landscape and bees

Although the landscape in the Hoeksche Waard was formed in the same way and generally looks very similar, there is still a large variation in the landscape. There are quite a few different biotopes in the Hoeksche Waard. In every different biotope other bee species occur. Bees depend heavily on their habitat. Requirements bees set to habitats are: ● The presence of plants delivering pollen and nectar ● For males, structures they can use for navigation and demarcate their territory ● For females, suitable places for nesting ● The microclimate To predict which species could occur in the Hoeksche Waard, it is necessary to determine which of the for bees important biotopes are present in the Hoeksche Waard. The most important habitats are described in “De Nederlandse Bijen”. They are categorized in seven landscape types. Of these seven landscape types four can be found in the Hoeksche Waard.

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The landscape types and there for bees important biotopes present in the Hoeksche Waard are the following: 1. Rivers and tidal freshwater wetland. 1.1. Grassland 1.2. Wet vegetation adjacent to rivers 1.3. Grienden 1.4. Ruderal 2. Peatland 2.1. Peatland 3. Sea clay areas 3.1. Dikes 3.2. Creeks 4. Urban areas 4.1. Gardens 4.2. Urban green 4.3. Rivers and tidal freshwater wetland

This landscape type is rich in biodiversity. In some floodplains more than 110 bee species have been found. The wealth in flora and fauna species is caused by the many biotopes within this landscape. In the Hoeksche Waard this landscape is found along the rivers Oude Maas, Spui, Hollands Diep and Haringvliet.

Grassland The grasslands near rivers are rich in flowers, forming nectar and pollen sources for wild bees. Flowers like clovers, thistles and common comfrey are just some examples of important flowers for bees (Peeters et al, 2012). Approximately 2500 Ha of the Hoeksche Waard is grassland. Most of this is used for intensive agriculture, but not all of it. Extensive grassland is found at the Korendijkse slikken, Oosterse and Westerse laagjes, Oudeland van Strijen, Griendweipolder and Groot Koninkrijk and other smaller areas (HWL,1999).

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Wet vegetation adjacent to rivers Similar to the previous this biotope also contains important plant species for bees. Purple loosestrife, hemp-agrimony, cow parsley and marsh woundwort are a few of those plants. In the Hoeksche Waard this biotope is for example present on Tiengemeten, where the very rare Bombus muscorum and B. veteranus occur. They both visit the earlier mentioned plants ​ as well as water mint and fen ragwort (Peeters et al, 2012). Furthermore this biotope can be found at more places along the rivers, for example in the Geertruida-agathacomplex and the Korendijkse slikken (HWL,1999).

Grienden Grienden are a special type of forest. They consist mainly of willow species. The grienden were used for the production of willow branches, but nowadays only a few are still in use. They can be found at many places in the Hoeksche Waard, mostly along the Oude Maas and Hollands Diep. (HWL,1999). Willows are important nectar and pollen sources for bees early in the season as the are one of the first plants to bloom. There are 11 species of willows in the Netherlands and of those species are also present in the Hoeksche Waard (PWG, 2018). Some bee species , like Andrena mitis, A. vaga, A. ventralis and Colletes ​ ​ ​ ​ ​ ​ cunicularius, collect pollen exclusively from willows (Koster, 2017). ​

Ruderal Ruderal areas are heavily influenced by human disturbance. Often there is an excess of nutrients. Ruderal areas are often places where debris has been deposited or agricultural fields which are not in use anymore (Martens et al, 2018). In the Hoeksche Waard the old terrain of the Suikerfabriek near Puttershoek is a great example of a ruderal area (freenature).

Peatland

The peat landscape is very diverse. It changes continuously between open water to peat marches. Peat is an important habitat for species like Hylaeus pectoralis and the rare H. ​ ​ pfankuchi. Bee researchers do not often visit peat areas, so more interesting species can be ​ found. (Peeters et al, 2012) In the Hoeksche Waard the only area that could be considered peat is the Oudeland van Strijen. This area contains peat, but it is covered by 30 cm of clay (Stempher, 2016).

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Sea clay areas

This is the landscape that is found in most of the Hoeksche Waard. This biotope is very important for some bee species like Andrena flavipes, A. Chrysosceles and a significant ​ ​ ​ amount of bumblebees (Peeters et al, 2012).

Dikes Dikes can be an important biotope for bees, especially for bees feeding on leguminous. Chalicodoma ​ ericetorum, Megachile ligniseca, Melitta leporina and ​ ​ ​ ​ ​ Andrena wilkella are some of these species. Dikes are also the habitat of the rare Bombus ruderarius (Peeters ​ ​ et al, 2012). In the Hoeksche Waard the total length of the dikes is 151 km. Most of these dikes are used intensively, for example grazing by sheeps and to a lesser extent cows and horses. Only the dikes in possession of Hoekschewaards Landschap are managed extensively (HWL, 1999).

Creeks Creeks have unique flora compared to other biotopes in the Hoeksche Waard, especially those transferred to nature friendly management. The shores can be 10 to 20 metres wide. Where the top layer of earth has been removed the creek shores have become more humid or even show different ground types then before. Those creeks are also places where peat, which is mentioned earlier, comes to the surface. some important plants for bees growing on the creek shores are sea aster, purple loosestrife, red bartsia and hemp-agrimony (HWL,2006). These are important species for bees like Colletes halophilus, Melitta nigricans, ​ ​ ​ M. tricincta and lasioglossum species (Falk, 2015). ​ ​ ​

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Urban areas

Approximately 6.5% of the Hoeksche Waard was urban area in 1999 and it even increased in later years. There are no large cities in the Hoeksche Waard, only 25 villages. These villages differ from large villages like Oud-Beijerland and Numansdorp to smaller ones like Mookhoek and Schenkeldijk (HWL,1999). The urban area is an important biotope for bees. There are a lot of flowers, which form nectar sources for bees, and nesting opportunity is also widely available. Some species are even found more often in urban areas then in rural areas, like Osmia bicornis, O. cornuta, Anthidium manicatum and Anthophora plumipes ​ ​ ​ ​ (Peeters et al, 2012).

Gardens In the urban areas gardens are the most natural environment to bees. They are rich in flowers and increasingly rich in nesting places with the placement of bee hotels. Hylaeus ​ communis and Andrena bicolor are just two examples bee species possible to find in ​ gardens. In a garden in Gronsveld the staggering number of 133 bee species is recorded, but in the Hoeksche Waard those numbers are probably lower (Peeters et al, 2012).

Urban green Not only in gardens it is possible to have a rich bee diversity but also parks and other green areas in cities or villages can host a wide variety of bees. Parks with humid or bare grounds are important for bees, but especially parks with herbaceous vegetation can be very rich in bees. Species like Dasypoda hirtipes, Macropis europaea, Andrena chrysocles and ​ ​ ​ lasioglossum leucozonium can occur here (Peeters et al, 2012). ​

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Bees in the Hoeksche Waard

Recorded bee species in the Hoeksche Waard

At this moment 98 bee species have been recorded in the Hoeksche Waard. Most are common species, but a few are rare or threatened. 14 threatened species have been recorded. 1 species was presumably imported together with wood. The 14 species listed on the red list are: Extinct: Bombus ruderatus ​ Critically endangered: Bombus veteranus ​ Endangered: Bombus muscorum, B. rupestris, Andrena pilipes, Andrena rosea ​ Vulnerable: Bombus jonellus, B. ruderarius, B. vestalis, Nomada bifasciata, Nomada ​ fulvicornis, Andrena gravida, A. labialis, A. wilkella

Figure 4.0 shows the recorded bee species in the Hoeksche Waard. This list is based on the data from www.hwl.waarneming.nl, “De Nederlandse bijen” by Peeters et al and “Effecten ​ ​ van agrarisch natuurbeheer in de Hoeksche Waard op de diversiteit en abundantie van bloembezoekende insecten, in het bijzonder bestuivers” by Zeegers. First the english name is given, followed by the Dutch and Latin name. After the names the IUCN code is given, which was extracted from “Basisrapport voor de rode lijst bijen” by Reemer. LC = least concern, NT = near threatened, VU = vulnerable, EN = endangered, CR = critically endangered, EX = extinct, DD = data deficient. * = non-native specie, 1 = probably extinct in Zuid-Holland (Reemer, 2017). Figure 4.0: Recorded species in the Hoeksche Waard

Fork-tailed flower-bee Andoornbij Anthophora furcata LC

Hairy-footed Gewone sachembij Anthophora plumipes LC flower-bee

Western honey bee Honingbij Apis mellifera LC

Field cuckoo bee Gewone Bombus campestris LC koekoekshommel

Cryptic bumblebee Wilgenhommel Bombus cryptarum DD

Small Garden Tuinhommel Bombus hortorum LC bumblebee

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Tree bumblebee Boomhommel Bombus hypnorum LC

Heath bumblebee Veenhommel Bombus jonellus VU

Large red-tailed Steenhommel Bombus lapidarius LC bumblebee

White-tailed Veldhommel Bombus lucorum LC bumblebee

Moss carder bee Moshommel Bombus muscorum EN

Common carder bee Akkerhommel Bombus pascuorum LC

Early bumblebee Weidehommel Bombus pratorum LC

Red-shanked carder Grashommel Bombus ruderarius VU bee

Large garden Grote tuinhommel¹ Bombus ruderatus EX bumblebee

Red-tailed cuckoo bee Rode Bombus rupestris EN koekoekshommel

Forest cuckoo Vierkleurige Bombus sylvestris LC bumblebee koekoekshommel

Buff-tailed bumblebee Aardhommel Bombus terrestris LC

Vestal Cuckoo Bee Grote Bombus vestalis VU koekoekshommel

Zandhommel Bombus veteranus CR

Black-thighed epeolus Gewone viltbij Epeolus variegatus LC

Bleekvlekwespbij Nomada alboguttata LC

Bonte wespbij Nomada bifasciata VU

Fabricius’ nomad bee Roodzwarte Nomada fabriciana LC dubbeltand

Yellow-shouldered Geelschouderwesp Nomada ferruginata LC nomad bee bij

Flavous nomad bee Gewone Wespbij Nomada flava LC

Little nomad bee Gewone kleine Nomada flavoguttata LC wespbij

Blunthorn nomad bee Zwartsprietwespbij Nomada flavopicta LC

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Painted nomad bee Kortsprietwespbij Nomada fucata LC

Orange-horned Roodsprietwespbij Nomada fulvicornis VU nomad bee

Gooden’s nomad bee Smalbandwespbij Nomada goodeniana LC

Lathbury’s nomad bee Roodharige wespbij Nomada lathburiana LC

Fork-jawed nomad Gewone Nomada ruficornis LC bee dubbeltand

Yellow-legged nomad Geelzwarte wespbij Nomada succincta LC bee

Sandpit mining bee witbaardzandbij Andrena barbilabris LC

Gwynne’s mining bee Tweekleurige Andrena bicolor LC zandbij

Hawthorn mining bee Goudpootzandbij Andrena chrysosceles LC

Ashy mining bee Asbij Andrena cineraria LC

Clarke’s mining bee Zwart-rosse zandbij Andrena clarkella LC

Yellow-legged mining Grasbij Andrena flavipes LC bee

Bryony mining bee Heggenrankbij Andrena florea LC

Tawny mining bee Vosje Andrena fulva LC

White-bellied mining Weidebij Andrena gravida VU bee

Early mining bee Roodgatje Andrena haemorrhoa LC

Large meadow mining Donkere Andrena labialis VU bee klaverzandbij¹

Lichte Andrena mitis LC wilgenzandbij

Buffish mining bee Zwartbronzen Andrena nigroaenea LC zandbij

Grey-patched mining Viltvlekzandbij Andrena nitida LC bee

Black mining bee Koolzwarte zandbij Andrena pilipes EN

Small sallow mining Vroege zandbij Andrena praecox LC bee

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Broad-faced mining Fluitenkruidbij Andrena proxima LC bee

Perkin’s mining bee Roodrandzandbij Andrena rosae EN

Impuncate mini-miner Witbaarddwergzand Andrena subopaca LC bij

Grey-gastered mining Grijze rimpelrug Andrena tibialis LC bee

Grey-backed mining Grijze zandbij Andrena vaga LC bee

Roodbuikje Andrena ventralis LC

Wilke’s mining bee Geelstaartklaver- Andrena wilkella VU zandbij

Small shaggy bee Kleine roetbij Panurgus calcaratus LC

Early colletes Grote zijdebij Colletes cunicularius LC

Davie’s colletes Wormkruidbij Colletes daviesanus LC

Hairy-saddled colletes Duinzijdebij Colletes fodiens LC

Sea aster bee Schorzijdebij Colletes halophilus LC

Orange-legged furrow Roodpotige groefbij Halictus rubicundus LC bee

Great-banded furrow Breedbandgroefbij Halictus scabiosae LC bee

Bronze furrow bee Parkbronsgroefbij Halictus tumulorum LC

Hairy yellow-faced Tuinmaskerbij Hylaeus hyalinatus LC bee

Bloomed furrow bee Berijpte Lasioglossum albipes LC geurgroefbij

Common furrow bee Gewone Lasioglossum calceatum LC geurgroefbij

White-zoned furrow Matte bandgroefbij Lasioglossum leucozonium LC bee

Least furrow bee Ingesnoerde Lasioglossum minutissimum LC groefbij

Green furrow bee Langkopsmaragdgr Lasioglossum morio LC oefbij

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Lobe-spurred furrow Kleigroefbij Lasioglossum pauxillum LC bee

Fringed furrow bee Gewone Lasioglossum sexstrigatum LC franjegroefbij

Shaggy furrow bee Biggenkruidgroefbij Lasioglossum villosulum LC

Orange-footed furrow Roodbruine groefbij Lasioglossum xanthopus LC bee

Bull-headed furrow Glanzende Lasioglossum zonulum LC bee bandgroefbij

Grote bloedbij Sphecodes albilabris LC

False margined blood Gewone Sphecodes miniatus LC bee dwergbloedbij

Box-headed blood Dikkopbloedbij Sphecodes monilicornis LC bee

Sandpit blood bee Schoffelbloedbij Sphecodes pellucidus LC

Sickle-jawed blood Grote Sphecodes puncticeps LC bee spitstandbloedbij

Reticulate blood bee Rimpelkruinbloedbij Sphecodes reticulatus LC

Wool carder bee Grote wolbij Anthidium manicatum LC

Shiny-vented Gewone kegelbij Coelioxys inermis LC sharp-tail bee

Large-headed resin Tronkenbij Heriades truncorum LC bee

Kirby’s mason bee Zwartgespoorde Hoplitis leucomelana LC houtmetselbij

Patchwork leafcutter Tuinbladsnijder Megachile centuncularis LC bee

Banded mud bee Lathyrusbij Megachile ericetorum LC

Brown-footed Gewone Megachile versicolor LC leafcutter bee behangersbij

Willughby’s leafcutter Grote bladsnijder Megachile wilughbiella LC bee

Red mason bee Rosse metselbij Osmia bicornis LC

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Gehoornde Osmia cornuta LC metselbij

Banded dark bee Geelgerande Stelis punctulatissima LC tubebij

Pantaloon bee Pluimvoetbij Dasypoda hirtipes LC

Yellow loosestrife bee Gewone Macropis europaea LC slobkousbij

Clover melitta Klaverdikpoot Melitta leporina LC

Loosestrife melitta Kattenstaartdikpoot Melitta nigricans LC

Red bartsia bee Ogentroostdikpoot Melitta tricincta LC

*Large carpenter bee* Blauwzwarte houtbij Xylocopa violacea EN * one observation in the stockroom of Paardekoper in Oud-Beijerland on 11-07-2018 (Oudshoorn, 2018). It was presumably imported together with wood.

Possible species in the Hoeksche Waard

- Zandloperbij - Ammobates punctatus very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Blauwe zandbij - Andrena agilissima ​ oligelectic very unlikely Figure 2.2: Model for oligelectic and monogelectic species

Factors Points

Habitat 0

Flowers visited for pollen 4

Nesting place 0

Distribution pattern -1

Total 3

- Matte dwergzandbij - Andrena alfkenella very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

22

- Geriemde zandbij - Andrena angustior ​ Polylectic Not likely Figure 1.2: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) -1

Total (7) 4

- Donkere wilgenzandbij - Andrena apicata ​ Oligelectic Very unlikely Figure 2.3: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 3

- Zilveren zandbij - Andrena argentata ​ Polylectic Very unlikely Figure 1.3: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 3

23

- Donkere rimpelrug - Andrena bimaculata ​ ​ Polylectic Very unlikely Figure 1.4: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 3

- Meidoornzandbij - Andrena carantonica ​ Polylectic Very likely Figure 1.5: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7 This species inhabits a large variety of habitats. Ranging from forest edges and dunes to heath and agricultural areas. It visits many plants but favours Rosaceae plants. It also often visits dandelion. Furthermore this species visits fruit trees and possible plays a role in there pollination. It nests without any preference in soil type. It is a common species and found almost everywhere in the Netherlands. This all results in the maximum score of 7 points, which means it is very likely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Goudstaartzandbij - Andrena chrysopyga ​ Polylectic Very unlikely This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

24

- Boszandbij - Andrena coitana ​ Polylectic Very unlikely This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Rimpelsnuit - Andrena combinata ​ Polylectic Very unlikely This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Gewone klokjeszandbij - Andrena curvungula Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Kruiskruidzandbij - Andrena denticulata ​ Polylectic Not likely Figure 1.6: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) 0

Total (7) 4

- Kruisbloemzandbij - Andrena distinguenda ​ Oligelectic Very unlikely This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

25

- Wimperflankzandbij - Andrena dorsata ​ Polylectic Very likely Figure 1.7: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7 Andrena dorsata is a common species in the south of the Netherlands. It lives in different habitats, including dikes and parks. It visits all kinds of flowers. The first generation visits blackberry, dandelion and willows often. The second generation mainly visits Apiaceae, like ​ ​ hogweed. It nests in bare places of different soil types, including clay. All of these factors are present in the Hoeksche Waard, making it very likely this species occurs here (Peeters et al, 2012).

- Zadeldwergzandbij - Andrena falsifica ​ Polylectic Very unlikely Figure 1.8: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

26

- Eikenzandbij - Andrena ferox ​ monolectic Very unlikely Figure 2.4: Model for oligelectic and monogelectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Gewone rozenzandbij - Andrena fucata ​ Polylectic Not likely Figure 1.9: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 4

- Texelse zandbij - Andrena fulvago ​ Oligeletic Very unlikely Figure 2.5: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 3

27

- Beemdzandbij - Andrena fulvata ​ Polylectic Very unlikely This species has recently been found in Limburg. This was the first observation of this species in the Netherlands. This makes it very unlikely this species is found in the Hoeksche Waard.

- Sporkehoutzandbij - Andrena fulvida ​ Polylectic Very unlikely Figure 1.10: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 0

- Heidezandbij - Andrena fuscipes ​ oligeletic Very unlikely Figure 2.6: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) not possible

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) not possible

28

- Gelderse zandbij - Andrena gelriae ​ Oligeletic Very unlikely Figure 2.7: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 2

Distribution pattern (-1 - 1) -1

Total (9) 5

- Knautiabij - Andrena hattorfiana ​ Monogelectic Very unlikely Figure 2.8: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) Not possible

Nesting places (0-2) 1

Distribution pattern (-1 - 1) 0

Total (9) Not possible At the moment it is not possible for Andrena hattorfiana to have a population in the ​ ​ Hoeksche Waard, since it collects pollen from field scabious. There is only one observation of this plant in the Hoeksche Waard. However field scabious is sow on dikes by the Waterschap. If those plants start to grow it might be possible to find A. hattorfiana in the Hoeksche Waard, since there is also a population in the Biesbosch. (Peeters et al, 2012; Van Gessele, 2018). This species is very unlikely to be resident in the Hoeksche Waard at the moment, however this might change in the future.

29

- Valse rozenzandbij - Andrena helvola ​ Polylectic Possible Figure 1.11: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 0

Total (7) 5 This species is found in forests and urban areas. It is polylectic on a variety of early blooming flowers, like dandelion and hawthorn. It is found in Zeeland, south Limburg and the higher grounds in the east. In Zeeland it is found on sand and on clay grounds. This species is increasing. This results in 5 points, which makes it possible that this species occurs in the Hoeksche Waard.

- Paardenbloemzandbij - Andrena humilis ​ Oligolectic Not likely Figure 2.9: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 5

- Noordelijke klaverzandbij - Andrena intermedia Very unlikely ​

This species is very rare and therefore it is not likely this species occurs in the Hoeksche Waard. Recent observations are from Drenthe only.

30

- Ereprijszandbij - Andrena labiata Polylectic Possible Figure 1.12: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) 1

Total (7) 6

This species is lives in a wide range of habitats. It is polylectic on many common plant species in the Hoeksche Waard. It nest in sandy places, which are not often found in the Hoeksche Waard. However this species also lives in gardens, where sand is sometimes found. It is found throughout the Netherlands. This results in 6 points, making it possible this species occurs in the Hoeksche Waard.

- Bosbesbij - Andrena lapponica ​ Oligelectic Very unlikely Figure 2.10: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) Not possible

Nesting places (0-2) -

Distribution pattern (-1 - 1) -

Total (9) Not possible

31

- Wikkebij - Andrena lathyri ​ Oligelectic Very unlikely Figure 2.11: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 2

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 3

- Oranje zandbij - Andrena marginata Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Gewone dwergzandbij - Andrena minutula ​ Polylectic Possible Figure 1.13: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) 1

Total (7) 6 This species occurs in almost every habitat. It collects pollen and nectar from almost every flower. As this species also occurs in urban areas, this species can nest in the sand found there. This results in 6 points out of 7 making it possible this species is found in the Hoeksche Waard.

32

- Glimmende dwergzandbij - Andrena minituloides ​ Polylectic Very unlikely Figure 1.14: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Donkere zomerzandbij - Andrena nigriceps ​ Polylectic Very unlikely Figure 1.15: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Schermbloemzandbij - Andrena nitidiuscula Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

33

- Gebandeerde dwergzandbij - Andrena niveata ​ Oligeletic Very unlikely Figure 2.12: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 1

- Bremzandbij - Andrena ovatula ​ Polylectic Not likely Figure 1.16: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) -1

Total (7) 4

- Donkere klokjeszandbij - Andrena pandellei Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Glimmende zandbij - Andrena polita Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Breedbanddwergzandbij - Andrena pusilla Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

34

- Roodscheenzandbij - Andrena ruficrus ​ Oligeletic Very unlikely Figure 2.13: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 3

- Rode zandbij - Andrena schencki Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Halfgladde dwergzandbij - Andrena semilaevis ​ Polylectic Very unlikely Figure 1.17: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) -1

Total (7) 3

- Roodstaartklaverzandbij - Andrena similis Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Lichte zomerzandbij - Andrena simillima Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

35

- Gekielde dwergzandbij - Andrena strobmella ​ Polylectic Very unlikely Figure 1.18: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) 0

Total (7) 3

- Breedrandzandbij - Andrena synadelpha ​ Polylectic Very unlikely Figure 1.19: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Tormentilzandbij - Andrena tarsata Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Zwartflankzandbij - Andrena thoracica Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Doornkaakzandbij - Andrena trimmerana Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

36

- Variabele zandbij - Andrena varians ​ Polylectic Possible Figure 1.20: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 0

Total (7) 6 This species is not very demanding, when it comes to habitat. It is mostly found along forest edges or in parks. It visits 12 plant families and is found often on hawthorn, blackthorn and dandelion. It is found on various soils and nest in small aggregations or alone. This species is spread across the Netherlands. It has shown a strong decrease, therefore it might be difficult to find this specie. There is also the possibility this species is already extinct in the Hoeksche Waard. Nonetheless it is is still a possibility this species still occurs in the Hoeksche Waard (Peeters et al, 2012).

- Groene zandbij - Andrena viridescens Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Kleine harsbij - Anthidiellum strigatum ​ Polylectic Very unlikely Figure 1.21: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

37

- Tweelobbige wolbij - Anthidiellum oblongatum Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Kleine wolbij - Anthidium punctatum ​ Polylectic Very unlikely Figure 1.22: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Mooie sachembij - Anthophora aestivalis Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Kleine sachembij - Anthophora bimaculata Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Noordelijke sachembij - Anthophora borealis Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Schoorsteensachembij - Anthophora plagiata Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

38

- Kattenkruidbij - Anthophora quadrimaculata ​ Polylectic Very unlikely Figure 1.23: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Zwarte sachembij - Anthophora retusa ​ Polylectic Very unlikely Figure 1.24: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Gewone pantserbij - Biastes truncatus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Lichte koekoeksbij - Bombus barbutellus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

39

- Tweekleurige koekoekshommel - Bombus bohemicus ​ cleptoparasitic Possible Figure 3.2: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 6 ​ ​ This species parasites Bombus lucorum, which is known in the Hoeksche Waard. B. lucorum is probably a common specie, therefore it is possible B. bohemicus is also present. However there are strikingly little recordings in Zuid-Holland. It will be hard to find B. bohemicus, however it could be possible (Peeters et al, 2012; Reemer 2017).

- Boloog - Bombus confusus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Waddenhommel - Bombus cullumanus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Gele hommel - Bombus distinguendus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Limburgse hommel - Bombus pomorum Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Late hommel - Bombus soroeensis Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

40

- Heidehommel - Bombus humilis ​ Polylectic Very unlikely Figure 1.25: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 2

- Grote veldhommel - Bombus magnus ​ Polylectic Very unlikely Figure 1.26: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 0

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 1

- Donkere tuinhommel - Bombus subterraneus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Boshommel - Bombus sylvarum Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

41

- Boomkoekoekshommel - Bombus norvegicus ​ cleptoparasitic Very unlikely Figure 3.3: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 3 ​ ​

- Blauwe ertsbij - Ceratina cyanea ​ Polylectic Very unlikely Figure 1.27: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 0

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 1

- Zuidelijke klokjesbij - Chelostoma distinctum Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

42

- Kleine klokjesbij - Chelostoma campanularum ​ Oligeletic Very unlikely Figure 2.30: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) not possible

Nesting places (0-2) 2

Distribution pattern (-1 - 1) 0

Total (9) Not possible

- Ranonkelbij - Chelostoma florisomne ​ Oligeletic Very likely Figure 2.14: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 2

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 2

Distribution pattern (-1 - 1) 1

Total (9) 9

This species occurs along forest edges, small scale agricultural areas and in cities. It is specialized on collecting pollen from Ranunculus plants. It nests in dead wood or hollow ​ stems. This species profits from the trend to place bee hotels in gardens. This species is mainly found in the east of the Netherlands and is scarcer in the west. It has however been found in Rhoon. This makes it very likely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

43

- Grote klokjesbij - Chelostoma rapunculi ​ Oligeletic Possible Figure 2.15: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 2

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 2

Distribution pattern (-1 - 1) 0

Total (9) 6

- Schubhaarkegelbij - Coelioxys afra Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Kielstaartkegelbij - Coelioxys alata Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Gouden kegelbij - Coelioxys aurolimbata Very unlikely ​ The only recent observations of this species are from Limburg therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

44

- Heidekegelbij - Coelioxys conica ​ cleptoparasitic Very unlikely Figure 3.4: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 2 ​ ​

- Grote kegelbij - Coelioxys conoidea ​ cleptoparasitic Very unlikely Figure 3.5: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 2 ​ ​

- Slanke kegelbij - Coelioxys elongata ​ cleptoparasitic Not likely Figure 3.6: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 4 ​ ​

45

- Duinkegelbij - Coelioxys mandibularis ​ cleptoparasitic Very unlikely Figure 3.7: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 1 ​ ​

- Rosse kegelbij - Coelioxys rufescens ​ cleptoparasitic Very unlikely Figure 3.8: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2)

Flowers visited for nectar (0 - 1)

Host species (not possible - 3) Not possible

Distribution pattern (-1 - 1)

Total (7) Not possible ​ ​

- IJszijdebij - Colletes impunctatus ​ Polylectic Very unlikely Figure 1.29: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

46

- Klimopbij - Colletes hederae ​ Polylectic Very likely Figure 1.28: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7

This species depends on ivy Hedera helix for its survival. It collects pollen from this plant and ​ only lives close to large growing places of ivy (Peeters et al, 2012). This southern species is colonizing the Netherlands via the south and has recently been found in Ooltgensplaat, Poortugaal and Rhoon (Waarneming.nl).

- Donkere zijdebij - Colletes marginatus ​ Polylectic Very unlikely Figure 1.30: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

47

- Zuidelijke zijdebij - Colletes similis ​ Oligeletic Possible Figure 2.16: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 2

Distribution pattern (-1 - 1) 0

Total (9) 7

- Heizijdebij - Colletes succinctus ​ Polylectic Very unlikely Figure 1.31: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 0

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) -1

- Gewone klokjesglansbij - Dufourea dentiventris Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Zandblauwtjesglansbij - Dufourea halictula Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

48

- Klokjesglansbij - Dufourea inermis Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Composietglansbij - Dufourea minuta Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Waddenviltbij - Epeolus alpinus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Bonte viltbij - Epeoloides coecutiens ​ cleptoparasitic Possible Figure 3.9: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

- Heideviltbij - Epeolus cruciger ​ cleptoparasitic Very unlikely Figure 3.10: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 2 ​ ​

49

- Schorviltbij - Epeolus tarsalis Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Gewone langhoornbij - Eucera longicornis ​ Oligeletic Not likely Figure 2.17: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) 4

- Zuidelijke langhoornbij - Eucera nigrescens Very unlikely ​ The only recent observations of this species are from Limburg and Gelderland therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Holkopgroefbij - Halictus compressus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Lombardgroefbij - Halictus langobardicus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Zuidelijke bronsgroefbij - Halictus leucaheneus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

50

- Heidebronsgroefbij - Halictus confusus ​ Polylectic Very unlikely Figure 1.32: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) ?

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) -1

- Blokhoofdgroefbij - Halictus maculatus Very unlikely ​ The only recent observations of this species are from Limburg therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Vierbandgroefbij - Halictus quadricinctus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Zesbandgroefbij - Halictus sexeinuctus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

- Emeraldgroefbij - Halictus smaragdulus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Zwaluwbij - Hoplitis anthocopoides Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

51

- Slangenkruidbij - Hoplitis aduca ​ Oligeletic Very unlikely Figure 2.18: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 1

Distribution pattern (-1 - 1) -1

Total (9) 2

- Geelgespoorde houtmetselbij - Hoplitis claviventris ​ Polylectic Not likely Figure 1.33: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 4

- Papaverbij - Hoplitis papaveris Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Klavermetselbij - Hoplitis ravouxi Very unlikely ​ The only recent observations of this species are from Limburg therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

52

- Driedoornige metselbij - Hoplitis tridentata ​ Oligeletic Not likely Figure 2.19: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 2

Distribution pattern (-1 - 1) -1

Total (9) 5

- Rotsmetselbij - Hoplitis villosa Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Gekielde maskerbij - Hylaeus angustatus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Duinmaskerbij - Hylaeus annularis ​ Polylectic Very unlikely Figure 1.34: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

53

- Noordse maskerbij - Hylaeus annulatus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

- Kortsprietmaskerbij - Hylaeus brevicornis ​ Polylectic Very unlikely Figure 1.35: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 2

- Gestippelde maskerbij - Hylaeus clypearis Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

- Slanksprietmaskerbij - Hylaeus gracilicornis Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

- Kleine lookmaskerbij - Hylaeus leptocephalus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Kleine slanksprietmaskerbij - Hylaeus paulus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

54

- Gewone maskerbij - Hylaeus communis ​ Polylectic Very likely Figure 1.36: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7

H. communis is a widespread and common species. It inhabits various habitats and visits many different plants. It seems that this species is increasing and due to urbanisation it is now also found in the west. This makes it very likely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Poldermaskerbij - Hylaeus confusus ​ Polylectic Very likely Figure 1.37: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7

Like the former species, H. confusus is increasing likely due to urbanisation, although this ​ species is found less often in gardens than H. communis. Again similar to H. communis this ​ ​ ​ species is found in various habitats and visits many plants. It is very likely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

55

- Gehoornde maskerbij - Hylaeus cornutus ​ Polylectic Not likely Figure 1.38: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 4

- Boemerangsmaskerbij - Hylaeus difformis ​ Polylectic Not likely Figure 1.39: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 4

- Moerasmaskerbij - Hylaeus pfankuchi Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

56

- Brilmaskerbij - Hylaeus dilatatus ​ Polylectic Not likely Figure 1.40: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 2

- Weidemaskerbij - Hylaeus gibbus ​ Polylectic Possible Figure 1.41: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 0

Total (7) 5

This species is found along hedges and in gardens and parks. It is polylectic, one of its favourite plants however is blackberry. It is rarer than the very similar H. confusus. This ​ ​ makes it possible this species occurs in the Hoeksche Waard (Peeters et al, 2012).

57

- Zompmaskerbij - Hylaeus gredleri ​ Polylectic Not likely Figure 1.42: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 4

- Rietmaskerbij - Hylaeus pectoralis ​ Polylectic Very likely Figure 1.43: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7

This species is quite rare in the Netherlands and is found mainly in the west. It only needs old reed vegetation. As there is a lot of reed vegetation in the Hoeksche Waard, it is very likely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

58

- Kleine tuinmaskerbij - Hylaeus pictipes ​ Polylectic Possible Figure 1.44: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 6

H. pictipes is found mainly in the southeast of the Netherlands. However this species occurs in urban areas and is possibly under recorded. This makes it possible this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Lookmaskerbij - Hylaeus punculatissimus ​ Oligeletic Not likely Figure 2.20: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 2

Distribution pattern (-1 - 1) -1

Total (9) 4

59

- Rinks maskerbij - Hylaeus rinki ​ Polylectic Very unlikely Figure 1.45: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Resedamaskerbij - Hylaeus signatus ​ Oligeletic Possible Figure 2.21: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 2

Distribution pattern (-1 - 1) 0

Total (9) 4

This species depends on Resedaceae plants for its survival. These plants are often found in ​ ruderal areas and are sometimes planted in gardens. This species increasing and colonizing new areas, therefore it is possible this species occurs in the Hoeksche Waard (Peeters et al, 2012).

60

- Stipmaskerbij - Hylaeus styriacus ​ Polylectic Not likely Figure 1.46: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 4

- Drievlekkige maskerbij - Hylaeus trinotatus Very unlikely ​ ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Rode maskerbij - Hylaeus variegatus ​ Polylectic Very unlikely Figure 1.47: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Gestippelde smaragdgroefbij - Lasioglossum aeratum Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

61

- Kortsprietgroefbij - Lasioglossum brevicorne ​ Polylectic Very unlikely Figure 1.48: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 0

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) -1

- Klokjesgroefbij - Lasioglossum costulatum Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Bosgroefbij - Lasioglossum fratellum ​ Oligeletic Very unlikely Figure 2.22: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) Not possible

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) Not possible

- Gladde groefbij - Lasioglossum laeve Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

62

- Slanke groefbij - Lasioglossum fulvicorne ​ Polylectic Very unlikely Figure 1.49: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 2

- Combigroefbij - Lasioglossum intermedium ​ Polylectic Very unlikely Figure 1.50: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

- Gedoornde groefbij - Lasioglossum leavigatum Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

63

- Breedkaakgroefbij - Lasioglossum laticeps ​ Polylectic Very unlikely Figure 1.51: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

- Breedbuikgroefbij - Lasioglossum lativentre ​ Polylectic Very unlikely Figure 1.52: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

64

- Gewone smaragdgroefbij - Lasioglossum leucopus ​ Polylectic Possible Figure 1.53: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) 1

Total (7) 1

L. leucopus is a common and widespread species. It has a preference for sandy soils, it is however also found on other soil types. It inhabits urban areas and flower rich grasslands. This makes it possible this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Schoorsteengroefbij - Lasioglossum lineare Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- glanzende groefbij - Lasioglossum lucidulum ​ Polylectic Very unlikely Figure 1.54: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 0

65

- Grote bandgroefbij - Lasioglossum majus Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Groepjesgroefbij - Lasioglossum malachurum ​ Polylectic Possible Figure 1.55: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) 0

Total (7) 5

This species nests in riverclay and feeds on flowers rich grasslands. It is found in Zeeland and in the along the greater rivers, west to Gorinchem. This makes it possible this species occurs in the Netherlands (Peeters et al, 2012).

- Zuidelijke dwerggroefbij - Lasioglossum minutulum Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

66

- Borstelgroefbij - Lasioglossum nitidiusculum ​ Polylectic Very unlikely Figure 1.56: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Glimmende smaragdgroefbij - Lasioglossum nitidulum ​ Polylectic Not likely Figure 1.57: Model for polylectic species

Factors Points

Habitat (0-2) 1

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) 0

Total (7) 4

67

- Waaiergroefbij - Lasioglossum pallens ​ Polylectic Very unlikely Figure 1.58: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

- Kleine groefbij - Lasioglossum parvulum ​ Polylectic Very unlikely Figure 1.59: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

68

- Viltige groefbij - Lasioglossum prasinum ​ Polylectic Very unlikely Figure 1.60: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 0

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) -1

- Fijngestippelde groefbij - Lasioglossum punctatissimum ​ Polylectic Very unlikely Figure 1.61: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 0

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) -1

- Dwerggroefbij - Lasioglossum pygmaeum Very unlikely ​ The only recent observations of this species are from Limburg therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

69

- Steilrandgroefbij - Lasioglossum quadrinotatulum ​ Polylectic Very unlikely Figure 1.62: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Kleine bandgroefbij - Lasioglossum quadrinotatum ​ Polylectic Very unlikely Figure 1.63: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

70

- Zadelgroefbij - Lasioglossum rufitarse ​ Polylectic Very unlikely Figure 1.64: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

- Glanzende franjegroefbij - Lasioglossum sabulosum ​ Polylectic Very unlikely Figure 1.65: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

71

- Halfglanzende groefbij - Lasioglossum semilucens ​ Polylectic Possible Figure 1.66: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) 0

Total (7) 4

- Noordelijke groefbij - Lasioglossum sexmaculatum Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Zesvlekkige groefbij - Lasioglossum sexnotatum ​ Polylectic Very unlikely Figure 1.67: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) 0

Total (7) 2

- Bergbosgroefbij - Lasioglossum subfulvicorne Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

72

- Duingroefbij - Lasioglossum tarsatum ​ Polylectic Very unlikely Figure 1.68: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) ?

Distribution pattern (-1 - 1) -1

Total (7) 1

- Bruine slobkousbij - Macropis fulvipes ​ Oligeletic Not likely Figure 2.23: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 2

Flowers visited for pollen (not possible - 4) 3

Nesting places (0-2) ?

Distribution pattern (-1 - 1) -1

Total (9) 4

73

- Bergbehangersbij - Megachile alpicola ​ Polylectic Very unlikely Figure 1.69: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Ericabij - Megachile analis ​ Polylectic Very unlikely Figure 1.70: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Dikbekbehangersbij - Megachile genalis Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Grote behangersbij - Megachile lagopoda Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

74

- Ruige behangersbij - Megachile circumcincta ​ Polylectic Very unlikely Figure 1.71: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Lapse behangersbij - Megachile lapponica ​ Oligeletic Not likely Figure 2.24: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 1

Distribution pattern (-1 - 1) -1

Total (9) 5

75

- Zilveren fluitje - Megachile leachella ​ Polylectic Very unlikely Figure 1.72: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 1

- Distelbehangersbij - Megachile ligniseca ​ Polylectic Very likely Figure 1.73: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 7

This rare species visits many different plants, but has a preference for thistles from the genus Cirsium. This species is quite rare, however it has also been recorded in Rhoon and ​ ​ Vlaardingen. This makes it very likely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

76

- Kustbehangersbij - Megachile maritima ​ Polylectic Very unlikely Figure 1.74: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 1

Distribution pattern (-1 - 1) -1

Total (7) 2

- Rotsbehangersbij - Megachile pilidens Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Pyrenese behangersbij - Megachile pyrenaea Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Luzernebehangersbij - Megachile rotundata Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

77

- Bruine rouwbij - Melecta albifrons ​ cleptoparasitic Possible Figure 3.11: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 2 ​ ​

- Witte rouwbij - Melecta luctuosa Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Klokjesdikpoot - Melitta haemorrhoidalis ​ Oligeletic Very unlikely Figure 2.25: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) Not possible

Nesting places (0-2) 0

Distribution pattern (-1 - 1) -1

Total (9) Not possible

- Zwarte wespbij - Nomada argentata Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

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- Knautiawespbij - Nomada armata ​ cleptoparasitic Very unlikely Figure 3.12: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) Not possible

Distribution pattern (-1 - 1)

Total (7) 2 ​ ​

- Kleine bleekvlekwespbij - Nomada baccata ​ cleptoparasitic Very unlikely Figure 3.13: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2)

Flowers visited for nectar (0 - 1)

Host species (not possible - 3) Very unlikely

Distribution pattern (-1 - 1)

Total (7) Very unlikely ​ ​

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- Langsprietwespbij - Nomada conjungens ​ cleptoparasitic Possible Figure 3.14: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​ The host species of N. conjugens is Andrena proxima, which has been found on ​ ​ ​ ​ Tiengemeten, but probably occurs in more places in the Hoeksche Waard. This makes it possible that N. conjugens also occurs in the Hoeksche Waard (Peeters et al, 2012; ​ ​ Waarneming.nl).

- Langsprietdwergwespbij - Nomada distinguenda Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Doornloze wespbij - Nomada emarginata Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Zwartbuikwespbij - Nomada errans Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

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- Dubbeldoornwespbij - Nomada femoralis ​ cleptoparasitic Not likely Figure 3.15: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2)

Flowers visited for nectar (0 - 1)

Host species (not possible - 3) Not likely

Distribution pattern (-1 - 1)

Total (7) Not likely ​ ​

- Glanzende dwergwespbij - Nomada furva Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Bruinsprietwespbij - Nomada fuscicornis ​ cleptoparasitic Very unlikely Figure 3.16: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 2 ​ ​

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- Gedrongen wespbij - Nomada guttulata ​ cleptoparasitic Not likely Figure 3.17: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) Possible

Distribution pattern (-1 - 1) -1

Total (7) Possibly 3 ​ ​

- Tweekleurige wespbij - Nomada integra ​ cleptoparasitic Very unlikely Figure 3.18: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2)

Flowers visited for nectar (0 - 1)

Host species (not possible - 3) Not likely

Distribution pattern (-1 - 1) -1

Total (7) Very unlikely ​ ​

- Vroege wespbij - Nomada leucophthalma ​ cleptoparasitic Possible Figure 3.19: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

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- Donkere wespbij - Nomada marshamella ​ cleptoparasitic Very likely Figure 3.20: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

- Vlekpootwespbij - Nomada melathoracica Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Eendoornwespbij - Nomada moeschleri Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Rode wespbij - Nomada mutabilis Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Gele wespbij - Nomada mutica Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Platkielwespbij - Nomada obtusifrons Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Boswespbij - Nomada opaca Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

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- Donkere dubbeltand - Nomada obscura ​ cleptoparasitic Very unlikely Figure 3.21: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) Very unlikely

Distribution pattern (-1 - 1) -1

Total (7) 0 ​ ​

- Sierlijke wespbij - Nomada panzeri ​ cleptoparasitic Possible Figure 3.22: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

- Kalkgraslandwespbij - Nomada piccioliana Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Neushoornwespbij - Nomada pleurosticta Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- kale wespbij - Nomada rhenana Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard(Peeters et al, 2012).

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- Kleine bonte wespbij - Nomada roberjeotiana Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Heidewespbij - Nomada rufipes ​ cleptoparasitic Very unlikely Figure 3.23: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) Not possible

Distribution pattern (-1 - 1) -1

Total (7) Not possible ​ ​

- Grote wespbij - Nomada sexfasciata Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Geeltipje - Nomada sheppardana ​ cleptoparasitic Possible Figure 3.24: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

- Grote stomptandwespbij - Nomada villosa Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

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- Signaalwespbij - Nomada signata ​ cleptoparasitic Possible Figure 3.25: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

- Matglanswespbij - Nomada similis ​ cleptoparasitic Very unlikely Figure 3.26: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) Not likely

Distribution pattern (-1 - 1) -1

Total (7) -1 ​ ​

- borstelwespbij - Nomada stigma ​ cleptoparasitic Very unlikely Figure 3.27: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) Probably extinct in Zuid-Holland

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

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- Stomptandwespbij - Nomada striata ​ cleptoparasitic Very unlikely Figure 3.28: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 2 ​ ​

- Variabele wespbij - Nomada zonata ​ cleptoparasitic Possible Figure 3.29: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

- Gouden slakkenhuisbij - Osmia aurulenta ​ Polylectic Very unlikely Figure 1.75: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

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- tweekleurige slakkenhuisbij - Osmia bicolor Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Blauwe metselbij - Osmia caerulescens ​ Polylectic Very likely Figure 1.76: Model for polylectic species

Factors Points

Habitat (0-2) 2

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) 1

Total (7) 2

- Kauwende metselbij - Osmia leaiana ​ Oligeletic Not likely Figure 2.26: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 2

Distribution pattern (-1 - 1) -1

Total (9) 4

- Waddenmetselbij - Osmia maritima Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

88

- Zwartbronzen houtmetselbij - Osmia niveata ​ Oligeletic Not likely Figure 2.27: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 1

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 1

Distribution pattern (-1 - 1) -1

Total (9) 5

- Boommetselbij - Osmia parietina ​ Polylectic Very unlikely Figure 1.77: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 2

Nesting places (0 - 2) 2

Distribution pattern (-1 - 1) -1

Total (7) 3

- Grote metselbij - Osmia xanthomelana Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Slurfbij - Rophites quinquespinosus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

89

- gedoornde slakkenhuisbij - Osmia spinulosa ​ Oligeletic Very unlikely Figure 2.28: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 2

Nesting places (0-2) 1

Distribution pattern (-1 - 1) -1

Total (9) 2

- Bosmetselbij - Osmia uncinata ​ Polylectic Very unlikely Figure 1.78: Model for polylectic species

Factors Points

Habitat (0-2) 0

Flowers visited for pollen and nectar (0 - 2) 1

Nesting places (0 - 2) 0

Distribution pattern (-1 - 1) -1

Total (7) 0

90

- Grote roetbij - Panurgus banksianus ​ Oligeletic Not likely Figure 2.29: Model for oligelectic and monogelectic species

Factors Points

Habitat (0 -2) 0

Flowers visited for pollen (not possible - 4) 4

Nesting places (0-2) 1

Distribution pattern (-1 - 1) -1

Total (9) 4

- Brede dwergbloedbij - Sphecodes crassus ​ cleptoparasitic Possible Figure 3.30: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

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- Bosbloedbij - Sphecodes ephippius ​ cleptoparasitic Not likely Figure 3.31: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 4 ​ ​

- Roestbruine bloedbij - Sphecodes ferruginatus ​ cleptoparasitic Very unlikely Figure 3.32: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 3 ​ ​

- Glanzende dwergbloedbij - Sphecodes geoffrellus ​ cleptoparasitic Possible Figure 3.33: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) Possibly 3

Distribution pattern (-1 - 1) 1

Total (7) 3 possibly 6 ​ ​

92

- Pantserbloedbij - Sphecodes gibbus ​ cleptoparasitic Possible Figure 3.34: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

- Lichte bloedbij - Sphecodes hyalinatus ​ cleptoparasitic Very unlikely Figure 3.35: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) Very unlikely

Distribution pattern (-1 - 1) -1

Total (7) 1 ​ ​

- Kleine spitstandbloedbij - Sphecodes longulus ​ cleptoparasitic Possible Figure 3.36: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

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- Kortsnuitbloedbij - Sphecodes majalis ​ cleptoparasitic Very unlikely Figure 3.37: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) Very unlikely

Distribution pattern (-1 - 1) 0

Total (7) 1 ​ ​

- Verscholen dwergbloedbij - Sphecodes marginatus ​ cleptoparasitic Not likely Figure 3.38: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 3 ​ ​

- Zwarte bloedbij - Sphecodes niger ​ cleptoparasitic Not likely Figure 3.39: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 0

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 3 ​ ​

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- Vroege bloedbij - Sphecodes rubicundus ​ cleptoparasitic Possible Figure 3.40: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

- Gestreepte bloedbij - Sphecodes rufiventris Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Wafelbloedbij - Sphecodes scabricollis ​ cleptoparasitic Possible Figure 3.41: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) 1

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

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- Kraagbloedbij - Sphecodes spinnulosus ​ cleptoparasitic Possible Figure 3.42: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) 0

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 1

Total (7) 6 ​ ​

- Gewone tubebij - Stelis breviuscula ​ cleptoparasitic Possible Figure 3.43: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 2

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) 0

Total (7) 5 ​ ​

- Minitubebij - Stelis minima Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

96

- Kleine tubebij - Stelis minuta ​ cleptoparasitic Very unlikely Figure 3.44: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 3 ​ ​

- Witgevlekte tubebij - Stelis ornatula ​ cleptoparasitic Very unlikely Figure 3.45: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 1

Distribution pattern (-1 - 1) -1

Total (7) 1 ​ ​

- Zwarte tubebij - Stelis phaeoptera ​ cleptoparasitic Very unlikely Figure 3.46: Model for cleptoparasitic species

Factors Points

Habitat (0 - 2) 1

Flowers visited for nectar (0 - 1) ?

Host species (not possible - 3) 3

Distribution pattern (-1 - 1) -1

Total (7) 5 ​ ​

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- Gele tubebij - Stelis signata Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Malvabij - Tetralonia malvae Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

- Vlekkenbij - Thyreus orbatus Very unlikely ​ This species is possibly extinct so it is very unlikely to occur in the Hoeksche Waard (Peeters et al, 2012).

- Grote harsbij - Trachusa byssina Very unlikely ​ This species is very rare and therefore it is very unlikely this species occurs in the Hoeksche Waard (Peeters et al, 2012).

Figure 4: the very likely and possible species of the Hoeksche Waard

Very likely Possible

Meidoornzandbij Valse rozenzandbij Resedamaskerbij Variabele wespbij Andrena Andrena helvola Hylaeus signatus Nomada zonata carantonica

Wimperflankbij Ereprijszandbij Gewone Brede dwergbloedbij Andrena dorsata Andrena labiata smaragdgroefbij Sphecodes crassus lasioglossum leucopus

Ranonkelbij Gewone Groepjesgroefbij Glanzende Chelostoma dwergzandbij Lasioglossum dwergbloedbij florisomne Andrena minutula malachurum Sphecodes geoffrellus

Klimopbij Variabele zandbij Halfglanzende Pantserbloedbij Colletes hederae Andrena varians groefbij gibbus Lasioglossum semilucens

Gewone maskerbij Tweekleurige Bruine rouwbij Kleine Hylaeus communis koekoekshommel Melecta albifrons spitstandbloedbij Bombus Sphecodes longulus

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Poldermaskerbij Grote klokjesbij Langsprietwespbij Vroege bloedbij Hylaeus confusus Chelostoma Nomada conjungens Sphecodes rapunculi rubicundus

Rietmaskerbij Zuidelijke zijdebij Vroege wespbij Wafelbloedbij Hylaeus pectoralis Colletes smilis Nomada Sphecodes leucophthalma scabricollis

distelbehangersbij Bonte viltbij Sierlijke wespbij Kraagbloedbij Megachile ligniseca Epeoloides Nomada panzeri Sphecodes coecutiens spinulosus

Donkere wespbij Weidemaskerbij Geeltipje Gewone tubebij Nomada Hylaeus incongruus Nomada Stelis breviuscula marshamella sheppardana

Blauwe metselbij Kleine tuinmaskerbij Signaalwespbij Osmia caerulescens Hylaeus pictipes Nomada signata

Comparison

In the Netherlands 331 bee species are regularly reproducing. In the Hoeksche Waard 98 species have been recorded. It is not clear if all of those species have populations in the Hoeksche Waard, since there is not enough data to prove this. 98 species is only 30% of the total species in the Netherlands. If we compare it to the total of bee species in Zuid-Holland this percentage is 44%. Both show the Hoeksche Waard is poor in bee diversity. (Reemer, 2018:1; Reemer 2017) In the Dutch red list of bees 181 species are included (Reemer, 2018:1). In the Hoeksche Waard only 14 of those species occur, which is only 8%. This shows the bees in the Hoeksche Waard are mostly ubiquitous species , without strict requirements of their habitat. The importance of the Hoeksche Waard for bees is therefore low.

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Figure 5: Comparison between the number of bee species in the Hoeksche Waard and the number of bee species in the Netherlands, in Zuid-Holland and between the number of bee species on the red list

The Netherlands Hoeksche Waard Percentage in the Hoeksche Waard

Total number of 331 98 30% species

Total number of 331 137 41% possible species

Total number of 222 98 44% species in Zuid-Holland

Total number of 222 137 61% possible species

Total number of 181 14 8% red list species

Extinct 46 1 2%

Critticaly 30 1 3% endengared

Endangered 42 4 10%

Vulnerable 38 8 21%

Near threatened 25 0 0%

Compared to Land van Wijk en Wouden

The Land van Wijk en Wouden is an area quite comparable to the Hoeksche Waard. Its landscape consist out of villages and polders. This makes it less diverse than the Hoeksche Waard, which also has the rivers and its adjacent areas. The other main difference is the soil. The land van Wijk en Wouden consists mainly of peat, in contrary to the sea clay of the Hoeksche Waard. In 2015 71 bee species have been found in this area (Reemer, 2015). This is only 28% less than in the Hoeksche Waard. In 2015 a project with the goal to make this area richer in flowers and bees. In 2018 this area was monitored again and now 91 bee species were found. This is an increase of 34%. At this moment this is only 7% less than in the Hoeksche Waard (Reemer, 2018:2). This shows the number of bees found in the

100

Hoeksche Waard is low, since the Land van Wijk en Wouden is less diverse. However this area has been monitored better, so this partly explains why the amount of species found is high when compared to the Hoeksche Waard. This also shows the potential of the Hoeksche Waard. With good monitoring more bee species will be found, but more importantly, if we take the correct measurements, more bee species can establish populations.

Species of priority

For the province Zuid-Holland 18 species of priority have been selected. Those are species for which more than 20% of the known sites lay in Zuid-holland or have an isolated population. Figure 6: Species of priority in Zuid-Holland and their status in the Hoeksche Waard

Species Known in the Hoeksche Likelihood in the Hoeksche Waard Waard

Andrena fuscipes no Very unlikely

Andrena hattorfiana no Very unlikely

Andrena niveata no Very unlikely

Andrena rosae yes -

Anthidium punctatum no Very unlikely

Bombus jonellus yes -

Bombus muscorum yes -

Bombus ruderarius yes -

Bombus veteratanus yes -

Coelioxys conoidea no Very unlikely

Coelioxys mandibularis no Very unlikely

Colletes succinctus no Very unlikely

Epeolus tarsalis no Very unlikely

Lasioglossum tarsatum no Very unlikely

Megachile leachella no Very unlikely

Osmia aurulenta no Very unlikely

Osmia spinulosa no Very unlikely

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Figure 7: Threatened species in Zuid-Holland

Species Known in the Hoeksche Likelihood in the Waard Hoeksche Waard

Bombus bohemicus no Possible

Andrena varians no Possible

Bombus ruderarius yes -

Bombus jonellus yes -

Megachile maritima no Very unlikely

Bombus rupestris yes -

Colletes succinctus no Very unlikely

Andrena fuscipes no Very unlikely

Andrena pilipes yes -

Species of priority in the Hoeksche Waard

At the moment 5 of the 18 species of priority in Zuid-Holland are recorded in the Hoeksche Waard. 4 of the 10 threatened species have been recorded in the Hoeksche Waard. In addition to the species of priority in Zuid-Holland, also threatend species which are charasteritic for the landscape of the Hoeksche Waard have been selected as species of priority for the Hoeksche waard.

Figure 8: The species of priority in the Hoeksche Waard and potential species of priority in the Hoeksche Waard.

Species of priority or Populations in the Species of priority in threatened in Hoeksche Waard the Hoeksche Zuid-Holland Waard

Andrena gravida likely potential

Andrena labialis yes yes

Andrena rosae species of priority yes yes

Andrena wilkella yes yes

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Andrena pilipes threatened unclear potential

Bombus jonellus both yes yes

Bombus muscorum species of priority yes yes

Bombus ruderarius both unclear potential

Bombus veteranus species of priority yes yes

Bombus rupestris threatened unclear potential

Nomada bifasciata likely potential

Andrena gravida This species has only been recorded twice in the Hoeksche Waard. Although it has been found in the surrounding areas more often. There are more observations from the Hellegatsplaten and from Rhoon. This makes it likely this species has also established populations in the Hoeksche Waard. There is an observation from Nomada bifasciata, the cleptoparasitic species of A. gravida, from ​ ​ ​ ​ 2007 in the Geertruida-agathapolder, indicating that A. gravida also ​ occurs there (Waarneming.nl). A. gravida lives in flower rich grassy areas. With the scaling up in ​ agriculture and eutrophication this habitat diminished and so did A. ​ gravida. It is listed as vulnerable on the red list. In the Hoeksche ​ Waard there are quite a few places where this species could occur like the Korendijkse slikken and the Oudeland van Strijen. Therefore it could be a potential species of priority for the Hoeksche Waard (Reemer, 2018:1).

Andrena labialis This species is specialized on Fabaceae, especially on clovers. Just as A. gravida this ​ ​ ​ species has suffered from the decrease in flowers. This species seems to be increasing in the Netherlands, after a large decrease. The species has been found on Tiengemeten in 2017. This could be the result of the increase or it was already present, but overlooked (Reemer, 2018:1; Waarneming.nl)

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Andrena rosae This species was found for the first time in the Hoeksche Waard in 2011. After a focused search this species was found in various places in the Hoeksche Waard. It was mainly found in areas close to the rivers, however also in some more inland polders. It was mainly found on hogweed, but also on wild carrot (Waarneming.nl). There are no actions that need to be taken for this specie. The only thing that could be done, is better monitoring of where this species occurs in the Hoeksche Waard.

Andrena wilkella Similar to A. labialis this species is also specialized on clovers. This species suffered from ​ the diminish in flowers, just as A. gravida and A. labialis. It occurs in all habitats, when it ​ ​ meets one condition. It needs enough Fabaceae plants, for the female to collect pollen. This ​ ​ species is quite rare and its distribution decreased with 27% since 1950. A. wilkella has ​ been found on Tiengemeten, the Korendijkse slikken and the APL-polder, but probably occurs in more places in the Hoeksche Waard (Reemer;1,waarneming.nl).

Andrena pilipes Andrena pilipes has recently only been found in areas recently transformed to nature along ​ the rivers. This species has 2 generations. The first visits Brassicaceae plants, but the ​ second visits does not visit any specific plants. In the Hoeksche Waard there is only one observation in from 2017. This was a male, not in the wright habitat. Therefore it is does not seem likely that this species has established a population there. However it might be worth to search for this species in the wright habitat. In Zuid-Holland the only other observations are from the Maasvlakte (Reemer, 2017; Waarneming.nl). If this species has populations in the Hoeksche Waard it can be considered a species of priority.

Bombus jonellus The only place this species is found in the Hoeksche Waard is Tiengemeten. This species lives in many habitats and the only condition seems to be that there need to be a lot of flowers. This species is classified as vulnerable and has shown a strong decrease in Zuid-Holland. It was only found in 3 areas on Goeree and Tiengemeten. For this species a bumblebee project has been started on Goeree and Tiengemeten.

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Bombus muscorum This species is found at multiple places near the Haringvliet. Also in the Hoeksche Waard this species has only been found along the Haringvliet shore. It has recently only been found in 7 plots in Zuid-Holland and has shown a strong decrease. For this species a bumblebee project has been started on Goeree and Tiengemeten.

Bombus ruderarius This species has only been found on Tiengemeten in the Hoeksche Waard. It is unclear if there is a population of this species in the Hoeksche Waard. It is possible, since its habitat, flower rich grasslands on clay, is found in the Hoeksche Waard in multiple polders. Focused searches for this species could reveal if there are populations in the Hoeksche Waard. Furthermore this species will also profit from the bumblebee project that has been started. If this species has populations in the Hoeksche Waard it can be considered a species of priority.

Bombus veteranus The distribution of this species in the Hoeksche Waard is similar to that of B. muscorum. The whole Dutch population is found along the Haringvliet and in the Biesbosch. 92% of the grids where this species occurs, are in Zuid-Holland. As this area is the most important area for B. veteranus, more knowledge needs to be acquired to what conditions it favours. If possible the habitat of this species needs to be enlarged. The bumblebee project will also look into this.

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Bombus rupestris This species is only found once in the Hoeksche Waard. It is classified threatened in Zuid-Holland, as well as in the Netherlands. This species is very similar to B. ruderarius and B. lapidarius. This makes it likely this species is overlooked. It is parasitic on B. lapidarius, which is common in the Hoeksche Waard. As this species is very similar to B. ruderarius focused searches for this species can be combined. Similar to the other bumblebee species , this species will profit from the bumblebee project. If this species has populations in the Hoeksche Waard it can be considered a species of priority.

Nomada bifasciata This species is cleptoparasitic on Andrena gravida. It occurs in the same habitat as A. ​ ​ ​ gravida and its decrease is linked to the decrease of A. gravida. It is listed as vulnerable on ​ ​ the red list. There are 2 recent observations in the Hoeksche Waard. One in the Korendijkse slikken and one in the Geertruida-agathapolder, indicating A. gravida also occurs there ​ (Reemer, 2018:1; Waarneming.nl). If this species has populations in the Hoeksche Waard it could be considered a species of priority.

Threats

Bee populations in the Netherlands have changed in the past years. 122 species have decreased, while 71 species have increased. In 2006 the bee diversity per 10 x 10 km grid has been studied. This showed that in 55% of the grids the amount of species has decreased, while only in 10% the amount of species increased. (EIS, n.d.). The Dutch landscape has changed a lot in the past decade. Changes in the scale of farming and urbanisation are examples of these changes. The bees are generally negatively impacted by these changes. These changes are determinative for the bee diversity.

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Scaling up in agriculture

The scale and intensity of agriculture has increased enormously in the past 60 years. Land consolidation and the more intensive use of land led to the disappearance of smaller elements in the landscape, like hedges and fences. Those small elements were important for bees as they formed food sources and nesting places. Scaling up and the more intensive use of the landscape by humans is seen as a very important factor in the decrease of bees worldwide and in also plays an important role in the Hoeksche Waard (EIS, n.d.).

Eutrophication

Due to fertilizers land becomes more nutrient-rich, which results in certain plants growing faster than others. In general this results in fewer plant species and less flowers, which again results in less bees (EIS, n.d.).

Reduction of flowers

Due to scaling up in agriculture and eutrophication less flowers are found in the landscape. This is an important reason for the decline of bees. A study found that not only bees decline, but also the plants pollinated by bees. Multiple studies also showed the specialist bees declined more than the generalists. Most of the plants visited by specialist bees also declined. Another study looked at the relation between flower preference, size and flight period. They also found that declined bees had a preference for declined plants. Strikingly often the declined bee species had a preference for Fabaceae or Lamiaceae, plant families which ​ ​ ​ ​ showed a strong decline due to changes in agriculture. This study also showed bees which have their flight period in spring had declined less than bees which have their flight period in summer. This has to do with the reduced availability of flowers in summer (EIS, n.d.).

Pesticides

The use of pesticides has increased substantially since the twentieth century. They are used against harmful insects, weeds and fungi. Studies have shown insecticides have negative effects on bees, which is not strange as their function is to kill insects. To what extent this played a role in the decline of pollinator populations is not clear, but there are studies that suggest they do (EIS, n.d.).

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Competition with honey bees

Honey bees are held in large colonies and cared for by beekeepers. This creates an unfair competition for food between wild bees and honey bees. With the reduction of flowers this competition gets more harsh. However the number of honey bee colonies also declined, so it seems honey bees suffer from the same factors as wild bees. Competition with honey bees can negatively impact local bee population, however it does not seem to be a determinative factor in the decline of wild bees (EIS, n.d.).

Recommendations

More research

First of all more research is needed, before other specific actions are taken. Specifically into the species of priority. It would be very useful to know if Andrena pilipes, A. gravida, Bombus ​ ruderarius, B. rupestris and Nomada bifasciata have populations anywhere in the Hoeksche ​ Waard. If so protection actions could be taken. Furthermore more monitoring is needed to find out which species occur in the Hoeksche Waard and specifically which red list species. Furthermore it is needed to examine where these species have their populations and what actions could be taken to improve their habitat.

Possible management actions

Apart from further research there are also actions that can already be undertaken to improve bee habitat. In general bees are depending on 2 things: enough food throughout their flight period and suitable nesting places. All different species have different preferences. This makes it impossible to take all species into account, when carrying out management actions. Therefore it is important to create a small-scale landscape. If a landscape is small-scale many species can inhabit it. Small-scale landscape includes different soil types, (small) height differences and variation in vegetation. It is also important to carry out management actions, like mowing, on small-scale, to secure food sources and nesting places throughout the bee season. Furthermore it is important for some species to keep a part of the vegetation unmowed in winter. Differing from the former regional actions, actions on national scale are also required. There is need for a national action plan to tackle problems as climate change, eutrophication and

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pesticides. In order for bees to adapt to climate change, it is necessary that they are able to colonize new areas, when it gets to hot in their current distribution range. As the largest part of the Hoeksche Waard is used for agriculture, actions to help bees are of utter importance. Unfortunately bees and biodiversity in general are under immense pressure in farmland. There is very little bees land still suitable for bees to survive. The areas bees still inhabit are generally line-shaped areas, like dikes and verges. These areas are usually quite narrow and unsuitably managed. Actions that could be taken are mostly focused on increasing the amount of flowers. An adaptation with good results is creating wide (6 metres minimum) field edges which are rich in flowers. Furthermore a different mowing policy, in which mowing happens phased and the clipping is taken away, is important. The sowing of flowers is usually less effective as many species, especially the rarer ones, are specialized on native flowers (Reemer, 2018:1)

Conclusion

At this moment 98 bee species have been recorded in the Hoeksche Waard, which is 30% of the total number of species in the Netherlands. However 37 more species could occur in the Hoeksche Waard, which would bring the total number of species to 137. This is 41% of the total number of species in the Netherlands. This proves that the hypothesis is wright. It is likely the populations of many bee species are under pressure in the Hoeksche Waard, although there are to few observations to prove this. It would require action from many different people, ranging from garden owners to farmers and the municipality, to create a more bee-friendly landscape. It is however possible and everyone would profit from a healthy ecosystem.

Discussion

First of all it would have been better to start earlier with this profile paper. I now started in September, which is close to the end of the flight period of most bees. Field work would not have yielded much, when carried out in September. It would have been better to start at the beginning of the season, in February or March. With a more early start more field work could have been carried out, which would result in more observations and likely more recorded species. Furthermore most of the data used for the literature study came from “De Nederlandse bijen” written by Theo Peeters. This is the most comprehensive book about bees in the

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Netherlands. It was however written in 2012. This means the data is 6 years old and a lot changed in those 6 years. Likely due to climate change some southern species colonized large parts of the Netherlands in a few years. In addition to this the species distribution is based on observations. Large areas however have not been studied very well. As a result of this the distribution maps are not always accurate. An example of this can be seen in Sphecodes niger. This species was only recorded in Limburg, until this year a population was found in Rhoon. I assumed it was not likely to occur in the Hoeksche Waard given it only occured in Limburg. However with the new information that S. niger has a population in Rhoon, which is 1 km away from the Hoeksche Waard, it seems likely this species could also occur in the Hoeksche Waard (Slikboer, 2018) This shows the knowledge about distribution of bees in the Netherlands is far from complete and is outdated very quickly. This has consequences for the assessed likelihood in the Hoeksche Waard of some species. It means some of the assessed likelihoods will be wrong. This will mainly be the case with species assessed as”‘very unlikely” or “not likely” as the distribution for “very likely” or “possible” species is already favourable. Moreover as bees can be hard to identify there is always the possibility of an observation being wrong. This is especially the case with data from Waarneming.nl, as this is mostly gathered by amateurs. Overall most data from Waarneming.nl is correct, however some difficult species, for example those that need to be determined with a microscope, can be misidentified. Misidentifications will affect the species list of bees in the Hoeksche Waard. Lastly it is unclear for many species if they are resident in the Hoeksche Waard or not. Most of the species in the Hoeksche Waard have only one or just a few observations. It is impossible to say if these species have populations in the Hoeksche Waard or are just vagrants. This can create a too positive image of the bee population in the Hoeksche Waard as there can be more species on the list of recorded species than species that really have populations in the Hoeksche Waard.

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Literature

● Bunjes H. e-mailed on 20-09-2018 ● EIS (n.d). “Oorzaak achteruitgang wilde bijen” visited on http://www.bestuivers.nl/bedreiging/oorzaken ● Falk, S. (2015) “Veldgids Bijen voor Nederland en Vlaanderen”, Utrecht/Antwerpen, Kosmos ● Hoekschewaards landschap (HWL) editors: Kievit, J.; Strucker, R.; Gelder-Verwoerd, F. de (2006) “Kreken van de Hoeksche Waard”, Oud-Beijerland, HWL ● Koster, A (2017) “Bevlogen… bijen en wilgen” visited on 22-12-2018 on http://www.bijenhelpdesk.nl/pdf/wilgenOase2017.pdf ● Linnartz, E “Kuipersveer” visited on 23-12-2018 on https://www.freenature.nl/kom-kijken/kuipersveer ● Hoekschewaards landschap (HWL) editors: Luitwieler, M.; Mesker, C.; Strucker, R.; Verkerk, J. (1999) “Vogels van de Hoeksche Waard” Oud-Beijerland, HWL ● Martens, M; Wissen, H van (2018) “Ruderaal” visited on 23-12-2018 on http://www.floravannederland.nl/home/plantengemeenschappen/hoofdgroepen/ruder aal/ ● Oudshoorn, J. interviewed on 16-12-2018 by Wilson Westdijk ● Peeters, T. M.J.;Nieuwenhuijsen, H.;Smit, J.;Meer, F. van der; Reamakers, I. P.; Heitmans, W. R. B.; Achterberg, K. van; Kwak, M.; Loonstra, A. J.; Rond, J. de; Roos, M.; Reemer, M (2012) “De Nederlandse bijen”, Zeist, KNNV ● Plantenwerkgroep (PWG) (2018) “Plantenregister van eerstwaarnemingen” ● Reemer, M. (2018:1) “Basisrapport voor de rode lijst bijen” ● Reemer, M. (2017) “De bijenfauna van Zuid-Holland: trends, prioritaire soorten en belangrijke gebieden” ● Reemer, M. (2015) “Bijen en zweefvliegen in het Land van Wijk en Wouden: nulmeting 2015” ● Reemer, M.; Kos, M.; Slikboer, L. (2018:2) “Bijen en zweefvliegen in het Land van Wijk en Wouden: herhaling 2018” ● Reemer M. e-mailed on 02-10-2018 ● Stempher, W (2016) “BEHEERPLAN BIJZONDERE NATUURWAARDEN OUDELAND VAN STRIJEN 2016 - 2021” Arcadis Nederland ● Slikboer, L; Noordijk, J; Zeegers, T “Bijzondere beestjes in het ‘Buijtenland van Rhoon’” visited on 04-02-2019 on https://www.naturetoday.com/intl/nl/nature-reports/message/?msg=24782 ● Torné-Noguera, A; Rodrigo, A; Arnan, X; Osorio, S; Barril-Graells, H; Léo Correia da Rocha-Filho, L; Bosch, J (2014) “Determinants of Spatial Distribution in a Bee Community: Nesting Resources, Flower Resources, and Body Size” visited on 30-11-2018 on https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4019551/#pone.0097255-Roulston1 ● Waarneming.nl visited on www.Waarneming.nl ​

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Sources photos

1. https://nl.wikipedia.org/wiki/Hoeksche_Waard_(eiland) ​ 2. http://vanhoekschewaarde.blogspot.com/2014/02/bezoek-de-hoeksche-waard.html 3. Wilson Westdijk 4. Sylvia Coolen 5. Jaco Visser 6. Wilson Westdijk

Attachment 1: Logbook

Date Work Hours

02-05 Visit to Tiengemeten 8

23-06 Visit to Tiengemeten 8

29-06 Searching for Andrena Rosae at Groot-Koninkrijk 4

06-07 Visit to Leenheerengorzenpolder 6

08-07 Searching for Andrena Rosae in Polder Raepshille + Land van 5 Essche + searching Melitta Nigricans in the APL-polder

12-07 Searching for Andrena Rosae around Strijen 3

13-07 Searching for Andrena Rosae at the Staart + Zomerlanden 8

14-07 Searching for Andrena Rosea in Polder Bonaventura 4

02-09 Searching for bees (especially bumble bees) at Tiengemeten 5

30-09 Making time schedule + approach + E-mailing 3

01-10 Working on approach 1

07-10 reading about bee studies 1

11-10 Working on bee studies in the Hoeksche Waard 1

06-11 E-mailing + working on bee studies 2

07-11 working on bee studies 3

08-11 Working on habitats in the HW 5

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13-11 Working on habitats in the HW 2

18-11 Working on habitats in the HW 1

22-11 Working on habitats in the HW 3

23-11 Working on habitats in the HW 5

25-11 Finishing Habitats in the HW 2

30-11 Making species list 2

01-12 Working on species models 3

02-12 Working on species models + accounts 3

03-12 Working on species accounts 1

16-12 Working on species accounts + comparison 11

17-12 Working on comparison + species of priority + threats + 6 recommendation

24-12/ Every day one hour of work on species accounts 7 30-12

28-1 Collecting pictures + making to do list 3

29-1 Working on remaining species accounts 2

30-1 Working on species accounts 2

31-1 Working on species accounts + lay out 1

01-2 Finishing species of priority 5

02-2 Labeling all tables + layout 3

03-2 Writing conclusion and discussion 4

04-2 Writing summary + recommendations 4

05-2 Photos + finishing recommandations 6

06-2 Checking layout + printing 2

Total 134

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