Ecologica Montenegrina 41: 56-61 (2021) This journal is available online at: www.biotaxa.org/em http://dx.doi.org/10.37828/em.2021.41.8

Further distributional records of Lethocerus patruelis (Stål, 1854) (: ) in

LEONIDAS-ROMANOS DAVRANOGLOU1 & IOANNIS KARAOUZAS2*

1 Department of Zoology, University of Oxford, OX1 3SZ, UK. E-mail: [email protected] 2Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research, Anavyssos, 19013, Attica, Greece. * Corresponding author: E-mail: [email protected]

Received 24 March 2021 │ Accepted by V. Pešić: 6 April 2021 │ Published online 11 April 2021.

Abstract Although the Indo-Eastern Mediterranean giant water bug Lethocerus patruelis (Stål, 1854) is Europe’s largest hemipteran and aquatic , its distribution in Greece has remained poorly understood. Only a handful of records exists from the Ionian Islands, Macedonia, Thrace, and isolated observations in Preveza (Epirus), Achaia (north-western Peloponnese) and the islands of Rhodes and Thasos. Using records from personal observations, biomonitoring data, online identification groups and museum collections, we expand the distribution knowledge of this to Aetolia-Acarnania, Thessaly, southern Peloponnese, Samothraki, North Sporades and the Cyclades. We also include a large number of new localities in areas within its previously known range.

Key words: Lethocerinae; ; true bugs; aquatic ; social networks; biogeography.

Introduction

Belostomatidae are the most charismatic of the true water bugs (Nepomorpha), due to their large size (up to 120 mm) and their voracious predatory habits, feeding on a wide range of , , turtles, and even birds (Matheson 1907; Ribeiro et al. 2018). The approximately 170 described species have a worldwide distribution, reaching their greatest diversity in the tropics (Schuh & Weirauch 2019). Europe’s sole belostomatid is Lethocerus patruelis (Stål, 1854), which in this continent is distributed in Albania, Bulgaria, Croatia, Greece, the Republic of North Macedonia, Montenegro, Serbia, and European Turkey (Grozeva et al. 2013; Polhemus 1995; Protić 1998; Perez Goodwyn 2006; Fent et al. 2011; Dulčić, et al. 2015). L. patruelis was also mentioned as present in Romania and doubtful in Hungary in Polhemus (1995), as well as present in the Romanian-Hungarian border in the map of Grozeva et al. (2013), without any associated citation. However, these records need verification, as subsequent checklists in these countries have not included any belostomatid (e.g. Boda et al. 2015). If L. patruelis indeed does occur in Romania, it will likely be found in the Danube Delta, or ports on the Romanian Black Sea coast, where they might be attracted by boat/ship lights. This species was recently recorded in Italy, likely reflecting a recent westward expansion (either natural or anthropogenic) (Bacchi & Rizzotti Vlach 2005; Cianferoni & Nardi 2013; Lo

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Parrino 2019). In Greece, despite its large size and high dispersal capabilities, sightings of L. patruelis are scarce. Its distribution is largely unknown, comprising scattered, isolated records in the Ionian islands, Macedonia, Thrace, Epirus, north-western Peloponnese and the island of Rhodes [distribution summarized in Corsini-Foka et al. (2019), but also includes the records of Zimmermann (1982), which were not included in the latter study]. The present work represents the most comprehensive study on the distribution of L. patruelis in Greece. Using records from personal observations, biomonitoring data, online arthropod identification groups and museum collections, we significantly expand the distribution knowledge of this species with new locations across the country (Aetolia-Acarnania, Thessaly, southern Peloponnese, Samothraki, North Sporades and the Cyclades), and we provide numerous records from its hitherto known range.

Material and Methods

Records from personal observations, museum collections, from the biomonitoring database of the Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research (HCMR) and from photograph-based records uploaded by citizens on social media groups and on arthropod identification websites were included. Given that L. patruelis is the only belostomatid species found in Europe and possesses an unmistakable morphology, we are confident that our social media photograph-based identifications are correct. A very similar species is L. cordofanus Mayr, 1853, and can be separated by morphological characters that are hard to see in most photographs. However, this species is distributed primarily in central tropical Africa (Polhemus 1995), (with southernmost record in South Africa) reaching the Middle-East through the Nile River basin, with the northernmost record being in Israel (Novoselsky et al. 2018). We therefore doubt that any of the records presented here could represent this species; however further research is needed to exclude this possibility. Acronyms: Specimen depositories HCMR – Hellenic Centre for Marine Research NMPC – National Museum of Prague, Czech Republic Websites IFG – Identifications (Αναγνωρίσεις) Facebook Group (https://www.facebook.com/groups/330623170293210) IGC – Insects of Greece and Cyprus (https://www.facebook.com/groups/708035362603739) IN – iNaturalist (https://www.inaturalist.org/taxa/541422-Lethocerus-patruelis)

Results

New Records. Aetolia-Acarnania: Acheloos river valley, between Lake Ozeros and Stratos Dam, remains of L. patruelis in pellets of black kites [Milvus migrans (Boddaert, 1783)], II.2017, (Alivizatos pers. comm.); Agrinio, city outskirts, 23.V.2016 (IFG); Messolonghi lagoon, live specimen, 14.X.2016 (IFG). : city centre, central square, live specimen captured by local residents, 6.X.2018 (IFG); , Karavomylos beach, 17.VI.2013 (IFG); Phthiotis, Parnassos Mt, 6 km north of Amfikleia, old camping area, 820 m. a.s.l., 24.IX.2014 (IFG); North Sporades islands: Skiathos, Koukounaries beach, dead specimen washed ashore, VI-VIII.2020 (Zogaris 2013); Skyros, 16.IX.2018 (IGC); Spercheios Delta, several live specimens eaten by white storks [Ciconia ciconia (Linnaeus, 1758)], remains found in their pellets, date uncertain, beginning of 2000 (Alivizatos pers. comm.). Epirus: Arta, live specimen collected in tube by local resident, 21.IX.2019 (IGC). Ionian Islands: Cephalonia, Argostoli seaside town, live specimen at house, 22.VI.2018 (IGC); Fiscardo seaside town, live specimen, 22.VIII.2020 (IN: Psomopoulou 2020); Kerkyra (Corfu): Kerkyra town, Kanoni area, near the airport, under street light, 39°36' N, 19°36' E, 10 m.a.s.l., 13.X.2018 (Karaouzas pers. obs.) Macedonia: Platamonas, near Platamonas beach, 23.XI.2020, (Efimeris Dimoprasion & Plistiriasmon 2020); Katerini: Katerini city centre: live specimen in backyard, 8.IX.2014 (IFG); live specimen at street light, 23.IX.2019 (IFG); Paralia Katerinis beach, live specimen walking at night 5.VIII.2018 (IFG); farmhouse in outskirts of Katerini, live specimen, 21.VII.2020 (IGC); Kavala: Kavala airport, live specimen walking on ground, 10.V.2014 (IFG); Kavala city centre, inside

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NEW RECORDS OF LETHOCERUS PATRUELIS FROM GREECE swimming pool, 27.VII.2020 (IGC); Kavala (unspecified location), live specimen walking on ground, 29.IX.2016 (IFG); Nea Peramos beach, live specimen, 18.X.2018 (IFG); Palio seaside village, live specimen walking on grass at night, 17.VIII.2019 (IGC); Zevgolatio, Strymonas River, 41°05´30.36’’ N, 23°17´34.90’’E, 22m, 24.IX.2015 (HCMR); Kerkini Lake, 1 live specimen caught in bird net, V.2016 (Alivizatos pers. comm.); Serres: Strymoniko village square, many specimens attracted to street lights, IX.2012 (IFG); : Akti Salonikiou beach, Agios Nikolaos, live specimen on beach, 7.VI.2019 (IN: Novakova 2019); lagoon, dead specimen, 21.XI.2016 (IFG); campus of Aristotle University, attracted to street light, 18.V.2016 (IGC); Epanomi beach, two specimens swimming at sea surface, VI. 2017 (IGC); Loutra Thermis, dead specimen, 2.X.2015 (IFG); Melissochori, Agias Praskevis, dead specimen, 2.X.2020 (IN: de Jager 2020); Nea Paralia Thessalonikis, 0 m. a.s.l., walking on pavement at night,19.IX.2018 (IGC); Nea Vrasna, dead specimen, 22.VII.2015 (IFG); Sochos, attracted to house light at night, 15.X.2020 (IFG); Thessaloniki, 1968, Arch. A. & Novák, P. legs., Kment det. (NMPC); Veria, city centre, Elias square, attracted to street light, 17.VIII.2017 (IGC). Peloponnese: Gythio, live specimen, 25.VIII.2019; Kalamata, city centre, attracted to street light, 37°2 '36.78"N, 22° 6' 46.86"E, 25 m. a.s.l., VII.2019 (IGC); Mt. Taygetos, Laconia, live specimen, 17.IX.2019 (IGC); North Aegean: Limnos Island, Kaspakas, 08.XI.2018 (Limnosfm100 2018); South Aegean (Cyclades): Amorgos island, dead specimen, 14.X.2018 (IN: Gavina 2018). Thessaly: Larissa, city centre, attracted to street light, 23.V.2017 (IFG). Thrace: Komotini, city centre, 21.VI.2020 (Xronos 2020); Rodopi, Xilagani, outside village church, 19.X.2018 (Tanea 2018); Samothraki Island, Vatos, 40°23’N, 25°36'E, 11 m a.s.l., dead specimen, XI.2012 (Skoulikidis pers. comm.); Evros, Lykofos, Lyra river, tributary of Evros River, 2 live specimens, IX.2015 (Zogaris pers. comm.); Kipoi village, at the Greek-Turkish border, live specimen walking on road, 19.VIII.2019 (IFG). Unconfirmed records. Due to its large size and unmistakable appearance, Lethocerus patruelis leaves a strong impression on the general public, often accompanied with fear. Members of the abovementioned online arthropod identification groups have claimed that they have seen L. patruelis in areas that coincide with the localities reported here and are therefore likely to be accurate: Messolonghi (described as particularly common), Cephalonia (reported to be much rarer than in the past), Ofriniou beach in Chalkidiki, Idomeni (abundant), and Parga in Epirus. Reports of L. patruelis from Lesbos Island in the North Aegean, where it is described by locals as a recent invasive, should be further investigated.

Discussion

In the present study, we recorded L. patruelis from numerous localities across Greece, which enhances our understanding of its distribution in the country (Fig. 1). Given that belostomatids are important in aquatic food chains (Corbet 1960), it is likely that L. patruelis could fulfill similar ecological roles in the ecosystems it inhabits in Europe; the records we provide here provide support to this assertion. Therefore, the conservation status of L. patruelis in Greek wetlands should be closely monitored. Our baseline distributional survey will be of essential importance towards this goal. Furthermore, it will be important to investigate whether this species merits inclusion in the Greek IUCN red list, as its wetland are of particularly high risk of degradation, especially in the drier central and southern parts of Greece (Zogaris et al. 2018). We make the following distributional and biological observations, which contribute to our understanding of this species: 1) The abundance of this species shows a clear north-to-south pattern, with observations becoming rarest towards the south. The species seems rare in the Peloponnese and other parts of the southern Aegean where wetlands are scarcer. The distribution of L. patruelis in the Peloponnese should be further investigated (especially in the wetlands of the western part of the peninsula), as it is presently particularly disjunct. This species has been reported to be expanding both westward and northward in other countries (Cianferoni & Nardi 2013; Lo Parrino 2019). Our observation of L. patruelis in Amorgos (Cyclades) might represent a specimen from Turkey (or another nearby island) that was carried by wind or sea currents, as this island appears to lack suitable wetland habitats. We should also not exclude the possibility that the Amorgos specimen may have been brought by tourist ferries or cruises, which have been proposed as possible transport mechanisms for the Italian populations (Cianferoni & Nardi 2013; Lo Parrino 2019). We conclude that L. patruelis is probably scarce and highly local in many parts of Greece, with only few records in

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southern Greece, but locally rather common in certain large lowland freshwater wetland areas, especially in northern and western Greece. 2) Regarding the biology of this species, adults most likely emerge in early May and are active until mid-November. Most of our observations took place in September-October (21 out of 44 records – or 47.7%), which presumably corresponds to the peak of adult activity. The unusually high reports of specimens in beaches or at sea strongly indicate that L. patruelis may have a strong preference for river deltas and slow-moving streams close to sea level, where its prey is particularly abundant. However, it is an adaptable species, as it can fly (and perhaps inhabit) to high altitude habitats in Mts. Parnassos and Taygetos, and it is also known from artificial habitats, such as ditches (Stephanides 1948). The dispersal capability of this species must be particularly high, as many residents who found specimens at their backyard or village stated that there are no bodies of freshwater anywhere near their residence. Finally, many important aspects of the species’ ecology are still poorly understood in Greece and these relate to requirements and its function in food webs. Our compilation provides the first evidence for predation of the species by white storks (Ciconia ciconia) and black kites (Milvus migrans) in Greek freshwater wetlands as documented in incidental observations by Dr. H. Alivizatos, a reputable zoologist with extensive experience in bird diet analysis. 3) Social networking platforms, especially Facebook, have proven to be useful resources for biodiversity inventories as they contain reliable biodiversity data (Chamberlain 2018). While used for a range of different purposes, social media platforms also provide a venue for sharing biodiversity-related content and posts on nature experiences. In many cases, citizens and nature enthusiasts, driven by curiosity, will post on social network groups their findings for identification, accompanied by vital information, including specific coordinates of latitude and longitude, or place name, showing the location where they were taken or posted. Crowd-sourcing data collection from nature enthusiasts is considered as one of the ways to effectively collect data when funding resources are limited (Di Minin et al. 2015). Our present work with L. patruelis provides an example of how social networks can contribute to our understanding on the distribution and biology of a poorly sampled, ecologically significant species.

Figure 1. Previous known records (grey circles) and new distributional records (black triangles).

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NEW RECORDS OF LETHOCERUS PATRUELIS FROM GREECE

Acknowledgements We are particularly grateful to Stamatis Zogaris (HCMR) and Haralambos Alivizatos for kindly sharing their unpublished records and observations with us. We would like to thank Petr Kment (NMPC) for providing distributional information on the specimens under his care and Nikolaos Skoulikidis (HCMR) for the record from Samothraki Island. We would also like to thank Gavril Marius Berchi and Fabio Cianferoni for reviewing our manuscript, and to the former for providing important information on the status of L. patruelis in Hungary and Romania. We also thank Christos Theodoropoulos (HCMR) for creating the map. We would foremost like to thank all the members and naturalists of online identification groups for uploading their observations and for their enthusiasm. This study would not be possible without their crucial input.

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