キバラアブおよびタカハシキボシアブの産卵植物とその卵塊

Abstract

Fourteen egg-batches of Hybomitra distinguenda (Verrall, 1909) were collected from 3 marsh plants, mainly Carex vesicaria L., in sunny places in Hokkaido from mid-July to early August. The eggs were laid on rather narrow and almost vertical leaves at an average height of 48.4cm above the water surface. The egg-batches were enamelled black in color, consisting of an average of 224 eggs, and elongate-flat in shape with 1 to 3 layers of eggs. Three egg-batches of Hy. takahasii Inaoka et Hayakawa, 1982 were collected from one marsh plant, Carex amplifolia, in shaded areas in Hokkaido in mid-August. The eggs were laid on rather narrow and upward-slanting leaves 49.7cm above the water surface. The egg-batches were black in color covered partly by greyish dust at the tips of the eggs, consisting of an average of 192 eggs, and roughly disk-like in shape with 2 to 3 layers of eggs. The eggs of Hy. takahasii were parasitized by wasps, but not those of Hy. distinguenda.