We examined host utilization pattern of the kleptoparasitic spider Argyrodes kumadai along a geographical gradient from central Japan to southwest Islands. Host species changed abruptly between Yakushima Island and Amami-oshima Island: Agelena silvatica (Agelenidae) in northern regions and Cyrtophora moluccensis (Araneidae) in southern regions. This is the first report showing allopatric host change in kleptoparasitic spiders.
A total of eleven females of Tetragnatha praedonia (Tetragnathidae) reared in the laboratory produced between one and seven cocoons during their life span. Brood size (the number of eggs per cocoon) varied from 47 to 234. The total number of eggs produced by a female spider varied greatly, from 82 to 1240 eggs, and was strongly correlated with the number of cocoons produced. These results suggest that Tetragnatha praedonia can make several cocoons during its life span if conditions, such as prey abundance, are favorable. Although the brood size was significantly correlated with the carapace length, the total number of eggs produced primarily depended on the number of ovipositions. Thus, well-fed individuals may construct more cocoons and consequently produce more eggs over a lifetime. The generational overlap in T. praedonia may be explained in part by the successive ovipositions of each female spider. Both the short life span and the successive ovipositions of T. praedonia appear to be advantageous in unstable and disturbed habitats.
Twelve new species of the family Uloboridae are described from China under the names, Hyptiotes fabaceus, H. solanus, Miagrammopes paraorientalis, Octonoba ampliata, O. aurita, O. dentata, O. digitata, O. paralingshanensis, O. paravarians, O. serratula, Philoponella lingulata and P. pisiformis. A key to Chinese genera of the family Uloboridae is presented.
A new zodariid species, Mallinella okinawaensis, is described based on the specimens from Okinawajima Is., which can be distinguished from the other species of the genus by U-shaped epigynal plate. The male of Mallinella sadamotoi (Ono & Tanikawa 1990) is described for the first time, and the additional records of female specimens are presented.
A new medium-sized species of the genus Cybaeus (Araneae: Cybaeidae) from Mt. Odaigahara, Honshu, Japan, is described under the name C. hatsushibai. The new species shows close similarities to C. aquilonalis inhabiting central to northern Honshu and the southwestern part of Hokkaido and C. aokii of central to eastern Hokkaido in external and genital morphology and they are allopatric in their distributions. Thus, they can be recognized as members of a single superspecies. It was found that in C. aquilonalis, the body size tends to be larger in populations in the northernmost Honshu and Hokkaido than those in the central Honshu. On the other hand, C. aokii, which seems to be allopatrically or parapatrically found in Hokkaido to the distributional range of C. aquilonalis, was much smaller than the latter.
This paper contains an annotated checklist of the 223 species and 41 subspecies classified in seven superfamilies, 29 families, 42 subfamilies and 62 genera recorded from Japan. The information on scientific name, Japanese name, synonym, type locality, and domestic distribution is given for each species and subspecies. The Japanese name for every taxonomic name is given due to its common use in Japan. Taxonomic remarks are noted as needed.