Arachnologische Mitteilungen 56

34 C. Hörweg & M. Řezáč legs are red-brown with darker rings (Reichholf & Steinbach 1997, Bellmann 2016, Bee et al. 2017, Nentwig et al. 2018). Steatoda bipunctata builds a three-dimensional web – usually in corners or niches – with a more or less thickly spun sheet with upwards and sideward directed threads to fix the net (Fig. 6). The catching threads are directed downwards. Only these have glue droplets, which are located at the bot- tom of the thread. Prey items become stuck here, and the spi- der hurries out of its retreat; usually a crevice near the web (Foelix 2015). Steatoda bipunctata can overpower not only small insects but even large spiders like the house spider. Steatoda bipunctata can be found all year round, how- ever males are usually encountered during the mating sea- son from June to October (Schaefer 1976). During mating the male makes chirping noises: the sounds are produced by pulling a sharp ridge at the front of the opisthosoma across a file-like ‘stridulatory organ’ at the back of the prosoma (Gwinner-Hanke 1970, Foelix 2015). In this way the female is enticed out of her retreat and mating can be completed. The female lays about 50–150 pink coloured eggs in a white egg sac which is hung within the web (Nielsen 1932, Bellmann 2016) (Fig. 7). Steatoda bipunctata is found in all European countries. Its vertical distribution is mostly from lowlands to low mountain ranges (up to about 800 m above sea level), although there are records up to 2000 m in the Alps (Wiehle 1937, Steiner & Thaler 2004). As a web-builder the species is mostly found in or on buildings, for example under window ledges or near front doors that stand back a little bit. Steatoda bipunctata can even survive in quite dry rooms (Reichholf & Steinbach 1997). As the name implies, rabbit hutches often make a suitable habi- tat as well. However, they are also found outdoors, mostly in gardens, on bushes and in forests – especially under tree bark – in rock crevices or under stones (Szinetár & Horváth 2006, Machač & Tuf 2016). In places they can be quite common and the species is not regarded as endangered (Řezáč et al. 2015, Blick et al. 2016). The known distribution in Europe can be found in specific distribution maps (Helsdingen 2017, Arachnologische Gesellschaft 2018, CSCF 2018, Czech Arachnological Society 2018, European Society of Arachnol- ogy 2018, MNHN 2018). Steatoda bipunctata can be mistaken for Steatoda castanea (Clerck, 1757), a species which lives in similar habitats but which mostly has a lighter colouration and is only found in spring (Nentwig et al. 2018, Wiki AraGes 2018). Steatoda bipunctata was chosen as the European Spider of the Year because this species is commonly found in houses and is relatively easy to recognize. Furthermore, it is an ex- ample of a cobweb spider which is not dangerous, unlike the widow spiders from the Mediterranean which are venomous to people and which are rightly feared and regularly menti- oned in the popular media; the chirping of the males is ano- ther peculiarity of the species. Acknowledgements Many thanks to all people involved in the voting and promoting processes of the Spider of the Year: Peter van Helsdingen who creates, together with the authors, the short-list of possible spiders, all the voting members for their participation and all translators who trans- late and adapt the text for the Spider of the Year for every country. Many thanks go to the photographers for providing pictures and to the webmasters of the different (not only arachnological) websites dealing with the information then. Last but not least thanks toTheo Blick (also for his gentle reminders), to Elisabeth Bauchhenss and Ambros Hänggi for important comments to improve the manuscript. References Arachnologische Gesellschaft (2018): Atlas of the European Arach- nids. – Internet: https://atlas.arages.de ; for Nuctenea umbratica https://atlas.arages.de/species/715 ; for Steatoda bipunctata https:// atlas.arages.de/species/124 (12 June 2018) Balkenhol B & Zucchi H 1989 Vergleichende Untersuchungen zur Überwinterung von Spinnen (Araneae) in verschiedenen Habitaten – Zoologische Jahrbücher, Abteilung für Systematik, Ökologie und Geographie der Tiere 116: 161-198 Bee L, Oxford G & Smith H 2017 Britain’s spiders. A field guide. Princeton University Press, Woodstock. 480 pp. Fig. 7: Steatoda bipunctata with eggs (photo: Stefan Sollfors, eurospiders. com) Abb. 7: Steatoda bipunctata mit Eiern (Foto: Stefan Sollfors, eurospiders. com) Fig. 6: Steatoda bipunctata within the web (photo: Cor Kuijpers, ARABEL) Abb. 6: Steatoda bipunctata im Netz (Foto: Cor Kuijpers, ARABEL) Fig. 5: Steatoda bipunctata – habitus (photo: Pierre Oger, ARABEL) Abb. 5: Steatoda bipunctata – Habitus (Foto: Pierre Oger, ARABEL)