Supercooling ability of the house spider, Achaearanea tepidariorum, is depressed by exogenous ice nucleators ingested with prey animals. To characterize the ice nucleators, the effect of heat exposure on the ice nucleating activity of the nucleators was examined. Spiders that fed on a heated isopod's gut (80-90°C) had a lower supercooling point (SCP) or temperature of crystallization than those that fed on an unheated gut. This result suggests that the ice nucleators limiting the supercooling ability of the predator are organic in origin.
We surveyed habitats of an endangered burrowing wolf spider Lycosa ishikariana (Saito 1934) along the San'in coast of Tottori and Shimane Prefectures, southwestern Honshu, Japan. The species was found from eight sites covering seven different beaches from Inasa Beach (Izumo City) in the east to Toda Beach (Masuda City) in the west in Shimane Prefecture for the first time. This extends the southwestern limit of the species' range ca. 160 km westward from the Yumigahama Beach of Tottori Prefecture, the present southernmost record. In the coast of Tottori Prefecture, the species was found from 17 sites that exceed known number of records in the area. The apparent increase of the number of habitats of the species in Tottori Prefecture is probably due to a shift of survey season from the mid summer to June when density of the burrows culminates by the recruit of newly hatched spiderlings. Simple logistic regression analyses suggested that presence/absence of the species is related to any of the sand grain sizes, sorting indices, areas, lengths and maximum widths of the sandy beaches, though a multiple logistic regression analysis revealed that beach areas and sand grain size were the most significant factors. According to the models obtained, requirements for the occurrence of species were estimated to be areas>0.0313 km2 (total length>985 m, width>60 m) of sandy beach, and sand grain diameter>0.33 mm.
As a result of a field survey to collect specimens of Suzukielus sauteri, a sironid species endemic to Japan, for molecular and chromosomal study, we confirmed occurrence of the species from six different localities covering the Tokyo, Kanagawa, Yamanashi, and Shizuoka Prefectures. This includes the Yamabushi Pass, near Lake Yamanaka of Yamanashi Prefecture, which enabled us to conclude that the type locality of the species, which has remained ambiguous for a long time, is Lake Yamanaka. All the known records of the species are provided and mapped for the first time.
A new lycosid species, Hippasa babai, is described using the specimens from Yonagunijima Is., which can be distinguished from H. holmerae Thorell 1895 by short male papal tibia as well as broad and thick projection of epigynum.
Six species of the genus Haplodrassus (Gnaphosidae) are reported from Japan: H. pugnans (Simon 1880), H. cognatus (Westring 1861), H. kanenoi Kamura 1995, and three new species. It became clear that a Japanese species was incorrectly identified with Haplodrassus montanus Paik & Sohn 1984, and this species is described as new to science under the name of H. hatsushibai. Furthermore, two new species are described under the names of H. mayumiae and H. nojimai.
A new spider species, Mendoza ryukyuensis sp. nov. (Salticidae) is described from the South-west Islands of Japan (Amami-oshima Island and Nakanoshima Island). Female of M. ryukyuensis resembles those of the other species of the same genus in appearance, but can be distinguished from them by genital structure. In contrast, male is easily distinguishable from those of other related species in both appearance and genital shape.