抄録
The seasonal development of Argopistes tsekooni was studied in a field in Ibaraki Prefecture, central Japan. This species has a univoltine lifecycle. Overwintered adults appeared on host trees from April with a peak in May. Eggs and leafmining larvae occurred in May–August (with a peak in June) and in June–September (with a peak in July–August), respectively. Larvae passed three instar stages in their mines. New adults emerged in August–September, and adults were observed until late September or early November. The sex ratio was 1 : 1. Overwintered females collected in May were reared at 20°C or 25°C under a photoperiod of 12L : 12D (12 h light:12 h dark), 13L : 11D, 14L : 10D and 15L : 9D. The longer the photophase became, the longer the oviposition period lasted and the larger the number of eggs was laid. This mechanism permits females to continue oviposition from late spring through mid-summer in fields. The ecological traits of A. tsekooni differed from those of the closely related species, A. coccinelliformis and A. biplagiatus in several respects. For example, the reproduction of A. tsekooni occurred in late spring–summer, whereas that of the other two species occurred mainly in early spring; A. tsekooni laid eggs more carefully than the others; and larvae of A. tsekooni did not change their mines, whereas those of the others sometimes (frequently in A. coccinelliformis) changed theirs.
