Ecological Studies of Spiders in Paddy Fields in Kinki (I)

[摘要] References(3)Cited-By(4)In order to bring to light the life-cycle of two species of spiders, Oedothorax insecticeps Bös. et Str. and Enoplognatha japonica Bös. et Str., the investigation was carried out under field and laboratory conditions at Sakai City from 1969 to 1970.The results of the observations were as follows. O. insecticeps has two generations a year. The adult appears from October to May and again from June to September. This spider passes the winter in the adult stage in the stubbles of rice plants. The eggs of the first generation are laid in the stubbles of rice plants during the period from March to June. During the standing of rice plants in paddy field, this spider inhabits around the rice stubbles. A female of the lst generation makes about 4 egg-sacs and 42 eggs are deposited in one sac. These egg-sacs are placed on stems of rice plants from late August to early October. The eggs hatch in 7-8 days in paddy field, and development from egg to adult takes 60 days in female, 55 days in male. This spider moults four times.E. japonica hibernates in various insters of nymphal period in the stubbles of rice plants. The adult appers from mid October to May and again from July to September. The lst egg-sacs are made in early June in the stubbles of rice plants and the clods of soil, and during the period from mid August to early October in the rice stubbles. After the rice transplantation, this spider inhabits around the rice stubbles. A female of the lst generation makes about 7 egg-sacs, and 120 eggs are deposited in one sac. The eggs hach in about 12 days in paddy field, and the development from egg to adult is completed in 75 days in female, 70 days in male. And they moult five times.

[学科分类] 动物科学