Breeding of Trithemis annulata in quarry lakes in the continental area of Italy 20. Dezember 2019137 Breeding of Trithemis annulata in quarry lakes in the continental area of Italy (Odonata: Libellulidae) Gabriele Gheza1, Gianluca Ancarani2, Carlo Chiari3, Claudia Corazzato4, Carlo Galliani5, Alexandro Minicò6, Fabio Sacchi7, Michael L. Sand8 and Alida Piglia9 1) Via G. Falcone 23, 27020 Tromello (PV), Italy, [email protected] 2) Via Turati 9, 27049 Stradella (PV), Italy, [email protected] 3) Via Donatello 261, 25124 Brescia (BS), Italy, [email protected] 4) Viale Abruzzi 6, 20068 Peschiera Borromeo (MI), Italy, [email protected] 5) Via Cherubini 7, 20037 Paderno Dugnano (MI), Italy, [email protected] 6) Via Gaetana Agnesi 4, 20814 Varedo (MB), Italy, [email protected] 7) Via Remesina interna 105, 41012 Carpi (MO), Italy, [email protected] 8) Via Trieste 12, 23888 La Valletta Brianza (LC), Italy, [email protected] 9) Via A. Cechov 21, 20151 Milano (MI), Italy, [email protected] Abstract In August 2018, an abundant breeding population ofTrithemis annulata was discovered in some quarry lakes located east of Milan (Lombardy, central Po Plain, northern Italy) and in Poncarale (province of Brescia, Lombardy). The autochthony of the species was confirmed due to the collection of ten exuviae and the observation of several dozens of tenerals and some hundreds of adult individuals. These are the first records of breeding populations of the species in the continental biogeographical zone of Italy. The presence of these popula- tions is discussed from the perspective of the progressive colonization of southern Europe and Italy by this Afrotropical species, which is fostered by ongoing global warming. Riassunto Riproduzione di Trithemis annulata in laghi di cava nell’area continentale d’Italia (Odo- nata: Libellulidae) – Nell’agosto 2018 un’abbondante popolazione riproduttiva diTri themis annulata è stata scoperta in una serie di laghi di cava situati alla periferia orientale di Mi- lano (Lombardia, Pianura Padana centrale, Italia settentrionale). L’autoctonia della specie è stata confermata grazie al ritrovamento di dieci esuvie e all’osservazione di decine di neosfarfallati e centinaia di adulti. Un’altra popolazione riproduttiva è stata scoperta in un altro lago di cava presso Poncarale (provincia di Brescia, Lombardia). Si tratta delle prime popolazioni riproduttive della specie accertate per la zona biogeografica continentale in Italia. La presenza di queste popolazioni viene discussa nella prospettiva della progressiva colonizzazione dell’Europa meridionale e dell’Italia da parte di questa specie afrotropicale, che è favorita dal riscaldamento globale attualmente in atto. Libellula 38 (3/4) 2019: 137–155 138 G. Gheza, G. Ancarani, C. Chiari, C. Corazzato, C. Galliani, A. Minicò, F. Sacchi, M.L. Sand & A. Piglia Zusammenfassung Entwicklung von Trithemis annulata in Baggerseen der Po-Ebene, Italien (Odonata: Li- bellulidae) – Im August 2018 wurde östlich von Mailand (Lombardei, zentrale Po-Ebene, Norditalien) an mehreren benachbarten Baggerseen eine große bodenständige Population von Trithemis annulata entdeckt. Durch die Aufsammlung von zehn Exuvien und die Be- obachtung mehrerer Dutzend frisch geschlüpfter und einiger hundert erwachsener Indivi- duen konnte der Bodenständigkeitsnachweis erbracht werden. Eine weitere reproduktive Population wurde an einem Baggersee in Poncarale (Provinz Brescia, Lombardei) nachge- wiesen. Dies sind die ersten Bodenständigkeitsnachweise dieser Art in Gewässern der kon- tinentalen biogeographischen Region auf dem italienischen Festland. Die Entdeckung der Populationen wird im Zusammenhang mit der fortschreitenden Besiedelung Südeuropas und Italiens durch diese afrotropische Libellenart diskutiert, welche anscheinend durch die anhaltende globale Erwärmung begünstigt wird. Introduction Odonata are increasingly recognized as reliable bioindicators of climate change ( 2015; et al. 2019). The effects of global warming on these in- sects include direct impacts on physiology, reproductive behaviour, phenology, dis- Hassall Termaat - tats and trophic relationships ( et al. 2007; 2008; tribution and dispersal 2008; abilities and indirect 2009). impacts Particularly due toevident modifications is the double of habi ef- fect that the increase of temperaturesHassall due to climateDingemanse change can have& Kalkman on the distri- butionHassall of & thermophilous Thompson odonata:Groppali it can foster poleward range expansion or shifts ( 2008; 2009; 2010; 2010; et al. 2019) and also allow them to colonize waterbodies at higher alti- tudesHassall than & was Thompson usual for thoseGroppali species ( De Knijf 2009; & Anselin 2010; Ott 2010). TermaatIn Europe, range expansions and/or shifts towards more northern latitudes Groppali Oertli Ott2007, 2010; et al. 2015; et al. 2019), warmer areas of south-western Eu- ropehave been( confirmed 2009) and from the continental British Isles areas ( of central et Europe al. 2005; (Ott et al. Brockhaus Termaat Grand Hickling Termaat favourable2019). Also temperatures, in the Mediterranean which now area allowsuch atheir phenomenon larval development has been observed: at more northernmany Mediterranean latitudes and species higher are elevations widening ( their ranges 2009; northwards, 2009). due to Under more in recent years ( et al. 2012, 2014; Grand 2015;Groppali et al. 2017; this trend, et al. the 2012, first 2017;records of some et al.African 2017; species in southern 2018), Italy occurredwhile in Rattu Soinski Condello Corso Viganò Cillo & Bazzato 2010; 2014;northern Italy et theal. 2015; first records et of al. colonization 2018) and also and records breeding of lowlandof Mediterranean species at higherdragonflies altitudes have are been increasing reported (e.g., recently (Zandigiacomo 2018). & Buian Subrero Uboni Rossi Festi Libellula 38 (3/4) 2019: 137–155 Breeding of Trithemis annulata in quarry lakes in the continental area of Italy 139 Trithemis annulata (Palisot de Beauvois, 1805) (Odonata: Libellulidae) is a wide- 2008;spread Afrotropical et al. 2009; species, which 2009; is expanding 2009). its range It is ina generalist southern andEurope pio- neerfrom speciesthe Mediterranean which can develop area mainly in waters as a consequence with low oxygen of climate concentrations change (Balzan ( - 2008)Boudot and whose larvaeGrand have a fast developmentGroppali ( et al. 2017), which also allows it to colonize temporary waterbodies ( et al. 2017). Bal zanDuring its ongoing expansion, this species is extendingBoudot its range along the Ital- ian peninsula northwards. The earliest records in ItalyBoudot refer to extreme southern and insular regions and date back to the end of the 19th century ( 1956; et al. 2017). Until the late 20th century this species was limited Conci & Nielsen- dinia: Boudot et al. 1985), but it has been reported recently in some regions of to southern regions (Lazio, Campania, Apulia, Basilicata, Calabria, Sicily and Sar Carchini 2013) and Emilia Romagnanorthern Italy,( always 2011). in areasIt has withrecently a Mediterranean been recorded bioclimate: also in Veneto in 2007, ( it was recorded 2018) andfor the is currently first time widespread in both Liguria in southern (Ottonello Italy,& Sicily,Oneto Sardinia and along the coast inFabbri central Italy ( 2018). Odonata. itThe previous scattered records of T. annulata in Lombardy referred to spo- radic and probably vagrantOdonata.it individuals (Piglia and Galliani, pers. obs.; cf. - Le Folaghe” park of Casei Gerola (province of Pavia) on 27. September 2015Odo by nata.it 2018). The first record for the region was a male observed at the “Parco- lations of this species ascertained for Lombardy and for the continental biogeo- graphicalA. Piglia and region C. Galliani. of Italy, The and aim to discussof this note this is colonization to describe thefrom first the breeding perspective popu of climate change, which is the main driver of the ongoing range expansion of this species ( et al. 2009). Boudot Study area The surveyed sites are located in the central Po Plain of Lombardy (northern Italy) (Fig. 1). The climate in the study area is warm temperate, with a mean an- nual temperature of 12.7°C (23°C of mean temperature in the warmest month, July, and 1.2–1.7°C of mean temperature in the coldest month, January) ( 2019). The mean annual rainfall is 915 mm (63 mm of mean rainfall in the driest month, February, and 105 mm of mean rainfall in the wettestClimate- month, October)data.org ( ). In Summer 2018, several waterbodies were surveyed in the surroundings of the Climate-data.org 2019 city of Milan (western Lombardy plain) and in the area south of Brescia (eastern Lombardy plain). Most of them were decommissioned or still active quarry lakes,- sinsone isfound a man-made in the study pond area: and they one areis a deeper,shallow wider, artificial have basin. a different Quarry bed lakes and have are distinctive features which make them different from other generic artificial ba Libellula 38 (3/4) 2019: 137–155 140 G. Gheza, G. Ancarani, C. Chiari, C. Corazzato, C. Galliani, A. Minicò, F. Sacchi, M.L. Sand & A. Piglia (e.g., ponds in private gardens and public parks) are usually shallower, smaller usually devoid of vegetation; in contrast, other artificial basins in the same areas and with aquatic vegetation. - riculturalThe surveyed landscape sites are south briefly of Brescia described (Fig. here. 1). The Sites two 1–10 groups