Agroeca dentigera (Liocranidae)

Jonsson, Lars J., 2005, Agroeca dentigera and Entelecara omissa (Araneae: Liocranidae, Linyphiidae), found in Sweden, Arachnologische Mitteilungen 29 (1), pp. 49-52 : 49

Agroeca dentigera (Liocranidae)

A. dentigera Kulczynski, 1913 was found on and in tussocks of Carex elata in a small semi-open mesotrophic coastal marsh surrounded by alder trees. In pitfall traps one female and one juvenile were trapped (26 March - 5 Apr. 1991) , one juvenile (14 May - 3 June 1991) , one male (7 - 30 Nov. 1991) the top of tussocks . Two males were found in the middle of a tussock that was cut in small pieces (27 Oct. 1991) . Agroeca dentigera has also been found previously at another locality on the coast of Scania. S. Almquist (pers. com.) found one female in a drift of Phragmites australis on a coastal pasture used by horses south of Klagshamn (55°30'N 12°55'E), 3 Sept. 1976. The female was found in the area between the pasture and a belt of Phragmites in sea water.

Agroeca dentigera has been reported from a few places in Germany ( BRAUN 1967, WUNDERLICH 1975, PLATEN et al. 1999), Belgium ( JOCQUE 1977, JANSSEN 1991), Romania ( OLTEAN 1973, STERGHIU 1985), Poland ( KUPRYJANOWICZ 1997), the Netherlands (v. HELSDINGEN 1999), Wales (FELTON et al. 2004), Finland, Lithuania (KOPONEN et al. 2000, RELYS & DAPKUS 2002, RELYS et al. 2002), Belarus (MIKHAILOV pers. comm.), Ukraine ( MIKHAILOV 1997) and in Russia ( KULCZYNSKI 1913), eastwards to the Urals ( Esyunin & Efimik 1996).

The female originallydescribedby KULCZYNSKI, 1913, has later been figured by several arachnologists ( Braun 1967, OLTEAN 1973, Jocque 1977, Sterghiu 1985, Roberts 1998 and Felton et al. 2004). The drawing ofthe heart-shaped epigyne by GRIMM (1986) and the copy in HEIMER & NENTWIG (1991) is somewhat atypical. The male has been figured by WUNDERLICH (1975), JOCQUÉ (1977), Roberts (1998) and Felton et al. (2004). Figs. 1-2 show the pedipalp of a male and figs. 3-6 the epigyne of females from Sweden. WUNDERLICH (1975) found A. dentigera in a marsh with Carex lasiocarpa surrounded by an alder fen. JOCQUÉ (1977) found it among heather, Calluna vulgaris , on dry ground near water and among the grass Molinia caerulea on wet ground. According to him A. dentigera needs "the vicinity of wet acid soils”. It has also been reported from mosses of Sphagnum . ( BRAUN 1967, STERGHIU 1985, JANSSEN 1991). In Romania it has been found in a floating belt of Phragmites in the Danube delta and in association with Sphagnum ( OLTEAN 1973, STERGHIU 1985).The records in Finland and Lithuania are from peatbogs, both open and with pines ( KOPONEN et al. 2001, RÉLYS et al. 2002). The report from Wales is from a somewhat different environment, from a hollow in a fixed sand dune with Ammophila arenaria dominant ( FELTON et al. 2004). It seems that A. dentigera needs wet, thick heaps of vegetation, e.g. tussocks or mosses. It is obviously hygrophilous. Probably it spends the day in tussocks, mosses or other wet heaps and wanders, at least some ofthe time, on the surface during the night. The species is active in autumn and spring, but can also fall into pitfall traps during the winter. It is red-listed as vulnerable in Sweden (GÄRDENFORS 2005).

Figures

Fig. 1 - 2: Agroeca dentigera Kuiczynski, left male pedipalp: 1 - ventral view, 2 - retrolateral view. Drawings by Sven Almquist

Fig. 3 - 6: Agroeca dentigera Kulczyriski, female epigyne: 3 - dorsal view, newly moulted female, 4 - ventral view, newly moulted female, 5 - dorsal view, old female, 6 - ventral view, old female. Drawings by Sven Almquist.