Abstract
The immigration of the Hawaiian beet webworm moth, Hymenia recurvalis, in a vegetable field at Nobeoka, Kyushu, was investigated in 1992. The moths on two host plants, Spinacia oleracea and Amaranthus lividus, were collected every day with a sweep net from 19 May. Collected female moths were dissected to determine the number of matings and the maturity of their ovaries. The daily number of moths cuptured was one or zero for ten days prior to 6 June, but the total number of moths suddenly increased to 64 during 8-10 June. Every female moth collected before 6 June had mated and had matured eggs. However, the female moths collected in the above three days included 85, 94 and 88% mated moths and 67, 89 and 88% matured moths suggesting the arrival of fresh moths. Two rice leaf roller moths, Cnaphalocrocic medinalis, a migrant moth, were also collected. Synoptic charts indicated that a depression occurred in central China on 5 June and the front that accompanied the depression moved to the East China Sea and then moved eastward across Kyushu on 7 June. The movement of the front appears to have brought the increase of the moth.
