During recent several years, a nympharid subtropical fritillary, Argyreus hyperbius, became one of the commonest butterfly species near Nagoya City, central Japan, despite absence of Anasia chrysippus, an unpalatable model species to which A. hyperbius females mimic. There is no summer and winter diapause, and the population repeats several generations during a year. The developmental threshold is about 10℃ and thermal constant from egg-hatch to adult emergence is 480 degree-days. The maximum number of adult males flying in the study area (27 ha) is about 40 (2000) to 80 (1999). The main hosts during summer and autumn are wild violets, grown along roads, but those during spring are pansy and viola. Although sex ratio of emerged adults is near 0.5, only a few females are seen during line-transect surveys, possibly due to predation by birds, which have no experience of feeding of unpalatable models. Removal of violets by weeding is considered to be an important mortality factor of larvae.

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Stored-product insect pests and their natural enemies were investigated on Okinawa-jima and Ishigaki-jima Islands, Okinawa, Japan. Twenty-four species belonging to five orders, Dermaptera, Hemiptera, Coleoptera, Lepidoptera and Hymenoptera, were collected in the stored condition. Two assassin bugs, Pergrinator biannulipes Mont. et Sign. and Amphibolus venator Klug were found at mill factories on Okinawa-jima Island. These species are known as predators of stored-product insect pests, and represent the first distributional records in Japan.

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The ragweed beetle, Ophraella communa LeSage, was found in Chiba Pref. in August 1996 for the fist time in Japan. The beetle severely damaged the ragweed, Ambrosia artemisiifolia L. and expanded its distribution rapidly. The insect has been found in 35 of 47 Prefectures till the end of 2000.

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