著者

杉山 芬

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.65, no.10, pp.386-391, 1956-10-15

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This paper deals with the quantitative relations of a parasitic nematode to its host insect on the field near Midakedo Pond in Hirosaki, Aomori Prefecture. The parasitic nematode, not yet indentified but probably belonging to a species of Mermitata, is not found in Atractomorpha bedeli Bolivar (dominant or subdominant here), Ducetia japonica Thumberg and Homorocoryphus jezoensis Matsumura & Shiraki, but in Oxya japonica Willemse (subdominant or dominant), Conocephalus chinensis Redtenbacher and Conocephalus japonica Redtenbacher (both of the Conocephali being rarer than the other Orthopterous insects). Oxya japonica with the nematode may be rather inactive (Figs. 1 and 2) and some hosts have a milky white abdomen as seen from the dorsal side. The parasitic rates of the nematode in Oxya japonica, observed around Midakedo Pond, are different from those at the other stations (Table 1, Fig. 1 and Fig. 2), but the rates at St. 1, 1', 2', 3', 4 and 5 are different from those at St. 4, 9. 11'. The rate in the male host is not different from that in the female one. Observations of the nematode in Oxya japonica at St. 1, 1', 2', 3', 4 and 5, reveal a pattern of "concentrating distribution"(Fig. 4). This may be atributed to the movement of the hosts, and to the place where they are infected with the parasite.