Emergence Composition and Seasonal Change of Crane Flies (Diptera: Tipulidae) from Slow Sand Filter Beds in Japan

ABSTRACT

We studied seasonal change in adult crane fly emergence from slow sand filter beds in an inland climate area of Japan and identified a total of 12 genera and 20 species belonging to two families. Crane fly fauna in filter beds was dominated by two species Antocha (Antocha) bifida and Antocha sp. 1. Emerging adults of the two main species showed a significant seasonal change in body size (determined by wing length), which decreased steadily from spring to summer and increased again in fall. We speculate that water temperatures influenced the decline in the wing length of crane flies on such filter beds.