Arachnologische Mitteilungen 56

Arachnologische Mitteilungen / Arachnology Letters 56: 32-35 Karlsruhe, September 2018 Synanthropic spiders – sometimes just called ‘house spiders’ – are feared and loved at the same time. However, this is perfect for a spider of the year! After Pholcus phalangioides (Fuesslin, 1775) in 2003, Salticus scenicus (Clerck, 1757) in 2005 and Eratigena atrica (C.L. Koch, 1843) in 2008 (Kreuels & Jäger 2003, Jäger & Kreuels 2005, Jäger 2007), two more similar species were elected. Both of them took advantage of new mi- crohabitats available in homes and around houses in urbanized areas and were able to settle into human dwellings (Sacher 1983, Reinke 1997, Jocqué et al. 2016). Moreover, they share another habit: they are also bark-dwellers (Wunderlich 1982, Koponen 1996, Horváth & Szinetár 2002, Szinetár & Hor- váth 2006, Machač & Tuf 2016). This means looking under the bark of trees near houses may reveal a spider of the year! Election of the European Spider of the Year (ESY) The European Spider of the Year was chosen by 81 (2017) re- spectively 83 (2018) arachnologists from 26 European coun- tries (Albania, Austria, Belgium, Bulgaria, Croatia, Czechia, Denmark, Finland, France, Germany, Great Britain, Hun- gary, Ireland, Italy, Liechtenstein, Macedonia, The Nether- lands, Norway, Poland, Portugal, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland). Co-ordination is via the Natu- ral History Museum Vienna together with the “Arachnolo- gische Gesellschaft” (AraGes) and the European Society of Arachnology (ESA). It is a simple email vote: voting mem- bers choose their favourite spider out of six proposed species (partly genera). A majority wins! Through choosing the Spider of the Year we not only hope that this less popular group of animals will be brought to the fore, but we also hope that researchers can obtain new data about its current distribution. In this context, enjoy the Spider of the Year and help us with your locality records via photo- graphic documentation of this species. There are many societies supporting the Spider of the Year (see European Society of Arachnology 2018). Furthermore, every arachnologist is asked for support using those spider species as a ‘model’ to promote spiders in general (for more details see Hörweg et al. 2015). Nuctenea umbratica (Clerck, 1757)/Walnut Orb-weaver/ Spaltenkreuzspinne/épeire des fissures – Spider of the Year 2017 Nuctenea umbratica belongs to the family of true orb-weavers (Araneidae). This family has 3135 species worldwide, 100 of which are found in Europe (World Spider Catalog 2018, Nentwig et al. 2018). The genus Nuctenea is represented by two species in (Central) Europe (Blick et al. 2004, Nentwig et al. 2018). The orb weaver N. umbratica shows a high level of sexu- al dimorphism: female body length is 13–16 mm, males just 7–10 mm. The body is wide and flattened. The basic colou- ration is red-brown to black-brown, the legs are dark brown and the opisthosoma shows a dark, leaf-like pattern (foliati- on) (Figs. 1–2) which can have a light border (Reichholf & Steinbach 1997, Bellmann 2016, Nentwig et al. 2018). Nuctenea umbratica builds a relatively large orb web (up to 70 cm in diameter) with an eccentric form in which the hub of the web is always displaced towards the spider’s retreat (Bellmann 2016). The spider spends the day hidden in this retreat and sits in the middle of the web when it gets dark at night. Nuctenea umbratica can be found the whole year round, but mostly from July to October (Wiehle 1931, Sacher 1983, Nentwig et al. 2018). It feeds like other orb weavers mainly on flies, moths, but also winged aphids; many of which are agricultural pests (Nyffeler 1983).The spider itself is regularly preyed upon by the sphecid wasp Sceliphron curvatum (Smith, 1870) (Gepp 1995). Nuctenea umbratica is found throughout Europe (Blick et al. 2004, Nentwig et al. 2018). Its vertical distribution is pre- dominantly from flatlands to low hills (up to about 800 metres above sea level), with only a few records at higher elevations up to 1500 metres in places like Tyrol (Wiehle 1931, Hänggi et al. 1995, Steinberger & Thaler 1990, Thaler & Knoflach 2003).The species occupies various habitats. It was originally a bark-associated species (Wunderlich 1982, Balkenhol & Zucchi 1989, Steinberger & Thaler 1990, Szinetár & Hor- váth 2006, Machač & Tuf 2016) (Fig. 3), particularly found on dead standing wood with loose bark, but is now also found in urban environments like house walls and fences, especially Synanthropic is best: Nuctenea umbratica (Araneae: Araneidae) and Steatoda bipunctata (Araneae: Theridiidae) are the European Spiders of the Years 2017 and 2018 Christoph Hörweg & Milan Řezáč doi: 10.30963/aramit5605 Abstract. The European spiders of the year 2017, Nuctenea umbratica (Clerck, 1757), and 2018, Steatoda bipunctata (Linnaeus, 1758), are presented. Both species were originally bark-dwellers, but became more and more synanthropic. Their appearance and characteristics (e.g., ecology, habitat, phenology) are briefly described. The modality of the voting is given as well as the decisive criteria for the win. Keywords : bark-dweller, Europe, popular, Rabbit Hutch Spider, synanthropic, Walnut Orb-weaver Spider Zusammenfassung. Am liebsten im Haus: Nuctenea umbratica (Araneae, Araneidae) und Steatoda bipunctata (Araneae: Theri- diidae) sind die europäischen Spinnen des Jahres 2017 und 2018. Die europäischen Spinnen des Jahres 2017, Nuctenea umbrati- ca (Clerck, 1757), und 2018, Steatoda bipunctata (Linnaeus, 1758), werden vorgestellt. Beide Arten sind ursprünglich Rindenbewohner, wurden aber mehr und mehr zu Kulturfolgern. Ihre Merkmale und Eigenschaften (z.B. Ökologie, Lebensraum, Phänologie) werden kurz beschrieben. Der Wahlmodus sowie die für die Wahl entscheidenden Kriterien werden genannt. Christoph HÖRWEG, Natural History Museum Vienna, 3. Zoology (Invertebrates), Burgring 7, 1010 Vienna, Austria; E-Mail: christoph.hoerweg@nhm-wien.ac.at Milan Řezáč, Crop Research Institute, Drnovská 507, 161 06 Prague 6-Ruzynĕ, Czechia; E-Mail: rezac@vurv.cz submitted: 14.5.2018, accepted: 17.11.2018, online: 6.12.2018