富栄養湖周辺域におけるユスリカ成虫の休息場所としての沿岸植生の役割

Abstract

To clarify the role of waterfront vegetation for Chironomid midges and make it useful for control countermeasures, an investigation of the number of chironomid midges resting on each form of vegetation and how they use Phragmites australis was conducted on massively breeding Chironomus plumosus and Eifeldia dissidens. As a result, significant differences were observed in the number of resting chironomid midges according to the type of chironomid and vegetation. Chironomid midges rested on Melilotus alba with the highest density. As for C. plumosus, many chironomid midges tended to rest on plants which had many leaves per unit stem length. About 70% of chironomid midges which flew to P. australis stuck to the leaves. The difference in numbers was not significant for either side of the leaves. In light of the above, the fact that such varied forms of vegetation exist in the shoreline area would mean that the chironomid midges may avail themselves of all kinds of resting places of the kind. In addition, it was thought that were a larger vegetation area to be secured along a lake waterfront, these midges could effectively provide a buffer zone between human living space and their own habitats.