| Popis: |
Eleven species of wolf spiders were captured in paddy fields in Ishikawa Prefecture, 1987. Among them, Arctosa subamylacea, Pardosa laura, Pirata piratoides, and Pi. subpiraticus were most numerous. In order to know the seasonal fluctuation of each species for each district, Seasonal Distribution Index (SD-index) proposed by MORISHITA (1967) was calculated by using the data which were obtained from the paddy fields. According to MORISHITA, a low SD-index value indicates that the period appearing in the field becomes short. From the results of calculation of SD-index value in Ishikawa Prefecture, it was presumed that Pirata subpiraticus, Pi. piratoides, Pardosa laura, Pa. astrigera, and Arctosa subamylacea appeared for long period in the field. To list up the dominant species in the wolf spider community in Ishikawa Prefecture, Prosperity Index (P-index) proposed by MORISHITA (1967) was calculated by using species which were represented high SD-index values. It was considered that the dominant species of the wolf spider community occurring was Pirata subpiraticus, except in the field of Komatsu district, in which the dominant species were both Pirata subpiraticus and Pi. piratoides. From the data reported by several workers, e.g. HAMAMURA (1969), KAWARA et al. (1969), KOBAYASHI (1961), KOBAYASHI and SHIBATA (1973), OHKUMA (1977), YAMANO (1977), it was considered that the dominant species of wolf spider community occurring in paddy fields in southern part of Japan is Pardosa pseudoannulata, while in northern part of Japan is Pirata subpiraticus. |
