茨城県の畜鶏舎におけるハエ類の発生消長

Abstract

Fluctuation of fly fauna in livestock and poultry farms was studied at two sites in Ibaraki Prefecture from March to December 1989. A total of 116,042 flies (ca. 15 spp.) were collected with bait-traps. Four species of Muscidae accounted for 86.8% of the total flies collected; these were 28.7% Muscina stabulans Fallen, 24.1% Fannia sp., 23.4% F. canicularis L. and 10.6% Musca domestica L. At the Wakamiya site consisting of an oxenshed, a poultry farm, a cowshed, a swine farm and a house, M. stabulans occurred predominantly and showed a bimodal fluctuation that reached a high density in June and November. The density of M. domestica was relatively low, also showing peaks in June and November. On the other hand, at the Kibe site consisting of an oxenshed, a poultry farm and a house, Fannia sp. and F. canicularis predominated, and their densities reached peaks in June and July, followed by an abrupt decline in August. The number of flies collected showed a large variation among traps. This variation seemed to relate to the farm environment where flies are likely to prefer folds with poor ventilation or places where treacly feedingstuffs and powdered milk were stocked or handled. Furthermore, higher percentages of M. domestica were trapped in sunny and bright places, while higher percentages of M. stabulans and Fannia spp. occupied obscure and dim places.