Arachnologische Mitteilungen 56

Arachnologische Mitteilungen / Arachnology Letters 56: 24-31 Karlsruhe, September 2018 Old trees provide important microhabitats for arachnids, such as foliage, branches, trunk and hollows; bark cracks and cavities offer specific microclimatic and structural conditions (e.g. Wunderlich 1982, Nikolai 1986). Some arachnid spe- cies live on trees throughout the year, whereas others use trees only for certain periods, mainly for overwintering (e.g. Hor- váth & Szinetár 2002, Horváth et al. 2004). Some facultative bark-dwelling arachnids that usually live in the canopy are found on trunks and in cavities only from late autumn to early spring, i.e. while deciduous trees are without their leaves (Szi- netár & Horváth 2006). In Europe, spiders living in tree hollows have been studied sporadically (Martínez De Murguía et al. 2007, Niţu et al. 2009), but no detailed study focusing on this topic has been published yet. From Czechia, only a single study dealing spe- cifically with spiders (and some other invertebrate groups) in tree hollows has been published so far (Růžička et al. 1991). In contrast, pseudoscorpion occurrence in tree hollows is generally known (Beier 1963, Weygoldt 1969, Ranius 2002, Christophoryová et al. 2017b). In Europe, obligate hollow- dwelling pseudoscorpions belong mainly to the families Che- liferidae and Chernetidae (Beier 1963).The first contribution about pseudoscorpions from tree hollows in Czechia was pu- blished by Ducháč (1993a); pseudoscorpions were collected using pitfall traps installed in hollow trees in the Třeboňsko Protected Landscape Area. Šťáhlavský (2001) carried out systematic research in Prague and its surroundings, where pseudoscorpions were obtained from the mould of 101 tree hollows of 16 tree species. Šťáhlavský (2001) categorized the species found according to their relationship to tree hollows and defined Mundochthonius styriacus Beier, 1971, Dinochei- rus panzeri (C.L. Koch, 1837), Allochernes wideri (C.L. Koch, 1843), and Anthrenochernes stellae Lohmander, 1939 as species with a close relationship to this microhabitat. Later several additional records of pseudoscorpions from tree hollows ac- ross the country were mentioned in further faunistic publica- tions (Šťáhlavský 2006a, 2006b, 2011, Šťáhlavský & Krásný 2007, Šťáhlavský & Tuf 2009, Šťáhlavský & Chytil 2013). Various methods have been used to collect arboricolous arachnids. The most popular and effective are arboreal eclec- tors situated on trunks (e.g. Albrecht 1995, Blick 2011) or on branches (e.g. Koponen 2004). Pocket traps attached to the tree bark represent another effective method (e.g. Bogya et al. 1999, Horváth & Szinetár 2002, Isaia et al. 2006). Pit- fall traps have been used to sample arachnids in tree hollows (e.g. Růžička et al. 1991, Ranius & Jansson 2002) and on tree trunks (e.g. Pinzon & Spence 2008, Machač & Tuf 2016). Canopy-dwelling arachnids have been also sampled by cano- py fogging (e.g. Otto & Floren 2007). Sweeping and hand collecting were used as a simple method for collecting speci- mens from branches (Hansen 1992). Flight interception traps have been developed mainly to collect flying insects, those of the window trap type being employed in particular for cat- ching beetles in flight (e.g. Økland 1996). Flight interception traps have not been used primarily for sampling arachnids until now. The aim of the present paper was to collect original data about spiders and pseudoscorpions of old oaks growing in a Central European floodplain on the northern margin of the Pannonian basin, obtained by pitfall traps installed in tree Spiders and pseudoscorpions (Arachnida: Araneae, Pseudoscorpiones) in old oaks of a Central European floodplain Ondřej Machač, Jana Christophoryová, Katarína Krajčovičová, Jan Budka & Jiří Schlaghamerský doi: 10.30963/aramit5604 Abstract. Spiders and pseudoscorpions on old pedunculate oaks ( Quercus robur ) with tree cavities were studied in a Central European floodplain (South Moravia, Czech Republic). Altogether 322 specimens from 47 spider taxa and 71 specimens of six pseudoscorpion spe- cies were collected during 2010 and 2011 from tree cavities using two methods. More specimens and species of spiders were obtained from flight interception traps and more specimens and species of pseudoscorpions were obtained from pitfall traps. Remarkable records represent typical cavity dwellers, i.e. the spider Midia midas (Simon, 1884), the pseudoscorpions Larca lata (Hansen, 1884) and Apochei- ridium ferum (Simon, 1879), the latter occurs mostly under tree bark. Five arachnid species are listed in the Czech red list: Midia midas , Leptorchestes berolinensis (C. L. Koch, 1846), Dipoena erythropus (Simon, 1881), Larca lata and Dendrochernes cyrneus (L. Koch, 1873). Keywords: arboreal, Czech Republic, ecology, faunistics, solitary trees, tree cavity Zusammenfassung. Spinnen und Pseudoskorpione (Arachnida: Araneae, Pseudoscorpiones) in alten Eichen eines mitteleuropä- ischen Auwalds. Spinnen und Pseudoskorpione alter Stieleichen ( Quercus robur ) mit Baumhöhlen wurden in einer mitteleuropäischen Aue (Südmähren, Tschechische Republik) untersucht. Insgesamt wurden 322 Individuen aus 47 Spinnentaxa und 71 Individuen aus sechs Pseudoskorpionarten in den Jahren 2010 und 2011 mit zwei Methoden erfasst. Spinnen wurden in höhere Individuen- und Artenzahl mit Kreuzfensterfallen und Pseudoskorpione zahl- und artenreicher in Bodenfallen in Baumhöhlen gefangen. Bemerkenswerte Artnach- weise betreffen typischer Baumhöhlenbewohner: die Spinne Midia midas (Simon, 1884) sowie die Pseudoskorpione Larca lata (Hansen, 1884) und Apocheiridium ferum (Simon, 1879), letztere kommt vor allem unter Baumrinde vor. Fünf Arten sind in der Tschechischen Roten Liste enthalten: Midiamidas , Leptorchestes berolinensis (C. L. Koch, 1846), Dipoena erythropus (Simon, 1881), Larca lata und Dendrochernes cyrneus (L. Koch, 1873). Ondřej Machač, Department of Ecology and Environmental Sciences, Faculty of Science, Palacký University, Šlechtitelů 28, 783 71 Olomouc, Czech Republic; E-mail: machac.ondra@seznam.cz Jana Christophoryová & Katarína Krajčovičová, Department of Zoology, Faculty of Natural Sciences, Comenius University, Mlynská dolina B-1, Ilkovičova 6, 842 15 Bratislava, Slovakia; E-mail: christophoryova@gmail.com , krajcovic.katarina@gmail.com Jan Budka & Jiří Schlaghamerský, Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 661 37 Brno, Czech Republic; E-mail: jiris@sci.muni.cz , budkaj@gmail.com submitted 23.3.2018, accepted 13.11.2018, online 6.12.2018