中気門類ダニによるイエバエ卵・幼虫の捕食, とくに線虫を混入した場合

Abstract

Feeding preference of manure-inhabiting mesostigmatid mites, i.e., Macrocheles muscaedomesticae, Parasitus gregarius, and Uroobovella marginata, was determined when they were given a choice between the house fly eggs and first-instar larvae, Musca domestica, in a test container. Under the same condition, these mite species were given, further, a choice of fly eggs (or larvae) and the rhabditid nematode, Rhabditis elongata, as an alternative prey. Finally, predatory efficiency of the three mite species for house fly eggs was examined using fresh pig manure, to which nematodes were added. Both fly eggs and larvae were preferred coordinately by female adults of M. muscaedomesticae. The adults fed preferentially on fly eggs, even when they were given together with nematodes. On the contrary, proto- and deutonymphs of this species preferred to feed on nematodes over fly eggs. Adults and deutonymphal stages of P. gregarius preferred to feed on fly larvae over eggs. Moreover, deutonymphs of this species showed a preference for nematodes over fly larvae and also over fly eggs. Deutonymphs as well as adults of U. marginata destroyed more fly larvae than eggs, when they were given a choice between these two preys. Adults of both sexes of this species showed a preference for nematodes, when they were given a choice between nematodes and fly larvae or between nematodes and fly eggs. Deutonymphs of this species also aggregated and fed on nematodes much more than fly eggs. The rate of predation by female M. muscaedomesticae adults on house fly eggs was kept so high in the fresh pig manure, to which nematodes were added as in the media without nematodes. On the other hand, predatory efficiency of P. gregarius and U. marginata deutonymphs on house fly eggs was much suppressed by the presence of nematodes which were added into the media.