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Home , Epistrophe eligans, Hoverfly, Myathropa, Myathropa florea, Syrphus ribesii, Syrphus vitripennis

A guide to the Bayer Research Farm in Great Chishill

1 Orchard Farm, Great Chishill • Nesting and visiting birds ayer Crop Science’s farm in • Butterflies and moths Encouraging Great Chishill covers some 20 • Bhectares on a gently undulating • Successful fledging of barn owl 1. Food Sources Hoverflies do not have suitable clay plateau to the south west of chicks (as an indicator of small Growing just about any wildflowers will mouthparts to feed from pea- Cambridge, on the Hertfordshire populations) attract at least some hoverflies and a such as clover, lucerne or sainfoin border. It is a working farm set up variety of selected to that favour bees but will feed from to help the company research and Hoverflies continuously throughout the spring mints, both cornmint and watermint understand better, new crop protection Hoverflies are a group of Diptera () and summer would be preferable. and other Labiates such as thyme, products and new seed varieties. As comprising the Syrphidae with Traditional wildflower meadows are marjoram and so on. Some Crucifers its name implies, the farm used to be many being fairly large and colourful. often good places to look for hoverflies, are good such as the spring flowering an orchard and indeed, there remains Some of them, such as the Marmalade and there are several plants which cuckoo flower and hedge mustard; some apple and pear trees on the Hoverfly are generally common and are favoured. Common bramble is a later on water cress, oil seed rape and site used for testing of novel crop numerous enough to have a common magnet for various hoverflies and other other mustards are good. Poppies protection products. The majority of the name. Others such as such as bees as are other attract many insects and for later in farmland, however has been converted sepulchris are declining in numbers, wild species of the Rosa such the year, September onwards, ivy is into land suitable for combinable possibly due to a reduction in habitats. as the various wild roses, blackthorn invaluable for hoverflies and many crop trials. The farm is enclosed other late flying insects including bees. Some members of the family are and hawthorn provided they are with mature hedges and trees with a It has the added attraction that it thought to be of flowering allowed to flower. Various members of diverse range of habitats, including: produces its rich black berries in the plants and many are very active and the Umbellifera, in particular species • Reverted plum and apple orchards later in the flowering season such depth of winter and is an invaluable efficient hunters during their food source at that time for birds. • A number of small woodlands larval stages. Most are therefore as hogweed are good and have the and ponds considered to be beneficial insects advantage of not being particularly • A network of grass margins, ditches with only a few whose larval stages invasive weeds with the exception • and bird seed edges feed on underground bulbs etc. of ground elder and perhaps Queen being considered pests, most notably Anne’s lace. Various Compositae, monitoring funeralis which feeds on the daisy family, are also attractive to at Chishill commercially grown daffodil bulbs. many insects. Creeping thistle is one of the best but is particularly invasive First and foremost, this is a working Hoverflies are mobile over quite large farm which has to pay its way for and other Compositae may thus be distances and are easily attracted given preferred. Ox-eye daisy, common daisy, the company. Nevertheless, non- suitable flowers and environments. cropped areas are actively managed, dandelion, chicory and field scabious They are not social nor nest making for instance, are all good; however in a way that is entirely consistent insects so need a continuous supply with the promotion of biodiversity. the frequently sown hardheads does of food during their adult lives. Poor not seem to be particularly favoured. We believe that it is important to weather may be devastating to an maximise the resources that the adult population as they cannot farm has and we regularly measure survive long without a constant food pertinax feeding on bramble, key biodiversity indices, including: supply, unlike many species fruticosus that nest and store food as honey.

2 3 2. Water 3. Nesting sites for bees: The hoverflies lays eggs in the bee Several hoverflies, such as Eristalis Hoverflies as bee mimics nest, and the resultant larvae feed tenax, breed in water, favouring Several hoverflies breed in commensal on debris; the obvious “reward” ponds rich in rotting vegetation. Small arrangements with bees, particularly for such housekeeping activities neglected ponds, deep permanently bumble bees and with being the relative safety from wet ditches or old cattle watering (particularly hornets) and it follows that predators that the nest provides. ponds with high organic matter levels encouraging these species will also Likewise, zonaria, one of the are favoured. If cleared the organic encourage these particular hoverflies. UK’s largest flies, is approximately the matter dredged out should be left Volucella bombylus, for example is same size as an adult worker hornet piled at the pond edge to slowly a large , the size of the bumble which they mimic. They are recent rot away and will attract hoverflies bees it mimics. It comes in at least invaders into the UK and are spreading and beetles to lay eggs. Similarly if three different colour forms, white- rapidly North and Westwards. Their cuttings from hedges and woods can tailed as here mimicking the white larvae live in hornet’s nests feeding be chipped and left in piles they will and buff-tailed bumble bees, a off the debris and discarded bits of slowly ferment and rot and also attract red-tailed variety mimicking the red- food from their hosts. The adult’s insects, acting as a far more productive tailed and meadow bumble bees resemblance to hornets is uncanny natural source than simply leaving or and an all brown sort that mimics and a good strategy for avoiding being burning cuttings, as they may attract the common carder bumble bee. preyed on by other insects and birds. grass snakes and slow worms. Bees are of course excellent pollinators and wasps, including hornets, are extremely good natural predators of many injurious insects. Wasps in particular as they are busy hunting Leaving long grass field edges will and killing caterpillars and other pests encourage mice and voles, and the in their thousands. It is not until the presence of owls and kestrels at breeding season of their prey finishes Great Chishill shows that the habitat at August time that wasps become generated here is successful. It is in apparent when their diet changes their empty nest burrows that many to sugary sustenance such as bumble bees make their nests, and windfalls, picnic jams and suchlike. where these hoverflies cohabit.

The presence of owls and kestrels at Great Chishill shows that the habitat generated here is successful

4 5 Hoverflies at Orchard Farm

This account is of the hoverflies It should be noted that although there balteatus Cheliosa pagana eligans observed on the Bayer’s Orchard have been wild flower species plantings The ‘Marmalade hoverfly’. Cheliosa ssp are very A widespread and fairly Britain and Chishill’s common hoverflies. Most common medium sized Farm at Great Chishill in Essex over in previous years to encourage native commonest hoverfly; a are difficult to identify spring hoverfly. Two th th five visits on the 5 July 2018, 16 insects some of these had been well-known aphid predator. ‘little black jobs’. There were seen at Chishill in August 2018, 8th May 2019, 2nd June grubbed up in order to be resown It becomes very common were several species May 2019. Its larvae feed 2019 and 3rd July 2019. The dates were but this had not produced effective in the later summer months seen during most visits to on in trees. chosen because there are variations flower banks at the time of the visits. and is easily identified Chishill although in small as it is the only British numbers. C. pagana is in emergent species of hoverflies from It was notable that there was a rich hoverfly with double one of few that can be month to month with few present variety of other insects at Great Chishill stripes on its abdomen. easily identified because until May and few remaining after the such as beetles, butterflies, dragonflies, it alone in this genus has beginning of September. In fact dates orange antennae. The only true bugs, bees, various wasps etc. were further chosen because of the other one firmly identified weather, most flying insects preferring Many hoverflies are easily identified, was Cheliosa variabilis. warm dry days with sunny periods. however for accurate identification of some there is a need to capture Of the United Kingdom’s 270 species, Seen on all visits in small and examine under a dissecting 26 species were identified and several numbers. A common microscope. This was not done UK hoverfly. Two other more were not identified to species and for some species only a genus Eristalis ssp were seen, E. level. Neither were they present in was ascribed. Generally such The ‘Great pied hoverfly’. arbustorum and E. tenax. particularly great numbers. This is not E. pertinax is very similar flies are members of genii of very Seen in the orchard on three unexpected for an agricultural setting occasions. This hoverfly to E. tenax but differs in similar species usually occupying such as East Anglia where cultivation is quite large—about bee Eristalinus sepulchris having yellow/orange front similar ecological niches and A strange shaped fly with ‘feet’ and so is easy to is generally arable with little meadow sized—and has the habit accurate species identification is of hovering along paths obvious spots on its eyes. A separate from other Eristalis or pasture, as hoverflies are most probably of little importance. and rides in one spot. declining UK species often ssp. Both E. pertinax and frequently to be seen attending flower It is inquisitive and will associated with agricultural E. tenax are honey bee heads of wild flowers of which there Many of the following photographs suddenly dart to investigate ponds rich in organic matter mimics, indeed E. tenax were few present during my visits. were taken at Chishill, many were other insects and even such as old-fashioned cattle is sometimes known as ponds or ponds where Suitable habitats were found along taken elsewhere but all, with one humans before darting the ‘drone fly’. Their larvae there has been high levels feed on rotting vegetation, exception, are of species seen back to its favoured spot. field edges, in hedges, the ancient of fertilizer runoff. A small usually underwater and These first two hoverflies farm pond, the old plum orchard and on the farm in 2018 and 2019. number were seen around possess a long breathing are the only ones in the particularly around the small reservoir the pond at Chishill feeding tube extending from the end UK that have common with its sown banks which was on water cress flowers. of their abdomen and so are names in widespread use. resultantly the richest source of insects. known as ‘rat-tailed larvae’.

6 7 umbellatarum, auricollis and scalare These hoverflies are three very similar, common, small and slim summer hoverflies, seen in fair numbers Heliophilus pendulus Spherophoria scripta albimanus austrica around the reservoir and There are two common & Spherophoria ssp A few Platycherius ssp Pipiza ssp were seen elsewhere and shown species of Heliophilus and S. scripta is one of were seen. They are all occasionally. They are here as representative they can be very hard to the commonest UK small hoverflies that have medium sized hoverflies, of the group. Although distinguish. They are larger, hoverflies and was also the habit of closing their usually all black and difficult not closely related they bee sized, handsome flies so at Chishill; it is the only wings as soon as they land to accurately identify. P. with vertical stripes on Spherophoria that can and are thus impossible to austrica has a dark cloud corolla and are difficult to accurately their thorax resembling reliably be identified, it identify without capture. on its wings but others identify. All their larvae feed those of American Football has an abdomen that is This shot of P. albimanus of the genus have few These two Eupeopes on aphids whereas the referees. The male H. longer than its wings and in flight shows the identifying features. There species are both common adults feed on and hybridus is easy to identify thus is easily identified. distinctive grey marks on were probably more present in the UK and were both so are often seen in large however the females are Other ssp were probably its abdomen. It is a very than P. austrica which is the seen frequently at Chishill. numbers on wildflowers very similar to H. pendulus also present. They are common representative of easiest to identify without In E. corolla the yellow such as hogweed, cow but can be separated as perhaps the most difficult of this large genus in which capturing specimens. spots on the abdomen or ox-eye daisies. their hind tibia is mostly hoverflies to identify. Even the larvae feed on aphids Another group whose join up almost creating orange/yellow—not easy! experts using microscopes and the adults on pollen. larvae feed on aphids. stripes whereas in E. luniger cannot separate the they remain separate and females of some of these look like forward facing species. Their larvae ‘commas’. Their larvae feed are aphid eaters. on a wide range of aphids.

Leucozona lucorum Xylotta segnis pyrastri A widespread and One was seen in the Larger and boldly marked common UK hoverfly seen orchard. ssp are hoverflies. This is a mostly in spring and early woodlands hoverflies migratory species visiting summer. A few were seen pipens found where there is a lot from the Continent and not florea in May 2019 at Chishill. A smaller, relatively of damp rotting wood. resident in the UK but seen A common and widespread Another aphid predator. common and widespread in variable numbers most hoverfly during most of the hoverfly seen at Chishill on years. Two were seen in year but usually only seen several occasions, usually in the orchard in July 2019, singly. Present at Chishill on higher numbers in the later one a female laying eggs all visits, frequently around months. Their larvae feed on —these might hatch but the orchard. Their larvae wet, decaying vegetation. will probably not survive are found in water feeding winter. Their larvae are on rotting vegetation. once again aphid eaters.

8 9 The survey of hoverflies at Orchard Farm was undertaken by Geoff Vowles,a retired pathologist, now an amateur naturalist with a particular interest in how insects, wild plants, birds and interact together.

Volucella zonaria Volucella bombylus This is one of the UK’s A large fly, the size of the largest flies, approximately bumble bees it mimics. the same size as an adult It comes in at least three worker hornet which they different colour forms, mimic. They are recent white-tailed as here invaders into the UK and are mimicking the white ribesii and spreading rapidly North and and buff-tailed bumble Westwards. Their larvae live bees, a red-tailed variety There are three common in hornet’s nests feeding off mimicking the red-tailed UK species of Syrphus. the debris and discarded and meadow bumble bees Along with E. balteatus bits of food from their and an all brown sort that and Spherophoria ssp hosts. The resemblance mimics the common carder they are the commonest to hornets is uncanny bumble bee. This one was UK hoverflies and are the and a good strategy for seen in the orchard. They familiar common hoverflies avoiding being preyed on breed in the nests of the on garden and meadow by other insects and birds. bumble bee they mimic flowers.Syrphus ssp were and are rather variable in seen on all visits to Chishill occurrence. Common but in good numbers. They never in large numbers. closely resemble each other and are difficult to identify in the field although in the females, whose eyes do not meet at the top of their head, this can be done as in S. ribesii the hind femur is all Vespa crabro yellow and in S. vitripennis A hornet for comparison. the femur is mostly black.

All photographs taken by and copyright claimed by G. H. Vowles © Bayer CropScience Limited 2020

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