Ecological studies on wolf spiders (Araneae: Lycosidae) in a northwest area of Kanto Plain, central Japan: diel activity and habitat preference observed by pitfall trapping

Abstract

Interspecific differences in diel activity and habitat preference of wolf spiders (Araneae: Lycosidae) were observed by pitfall trapping in a northwest area of Kanto Plain, Japan. Pardosa agraria, P.astrigera and P.graminea were all collected only in daytime, and Pirata yaginumai and Pirata piratoides showed slightly diurnal and nocturnal tendency, respectively. Arctosa fujiii. Pirata clercki, Pirata procurvus, Pirata tanakai, and Tricca japonica can be regarded as aperiodic. Lycosid habitats were classified by combining qualities or grades of three environmental elements of substratum (B, bare soil; L, live plants; D, dead plants), light condition (s, sunshine; d, dark or shade) and water condition (0, rain alone; 1, standing water; 2, running water). Though every lycosid species occurred in three or more habitat classes, and seldom on upper parts of live plants, the highest frequency was observed in Bs0 in Pardosa astrigera, Ls0 in Pardosa graminea and Trochosa ruricola, Ls1 in Pirata clercki, Ls2 in Pardosa agraria, Pirata piratoides and Pirata yaginumai, Ds0 in Pirata procurvus and Pirata tanakai, Ds1 in Arctosa ebicha and Tricca japonica, and in Dd0 in Arctosa fujiii. Other seven lycosid species (Alopecosa virgata, Arctosa depectinata, Arctosa subamylacea, Lycosa coelestis, Pardosa pseudoannulata, Pardosa yaginumai and Pirata subpiraticus) in the study area were not or seldom trapped because of their low mobility or low density at the trapping sites. Differences between stages or sexes were obscure both in diel activity and habitat preference.