海洋性昆虫ウミアメンボHalobates japonicus Esaki (Hemiptera: Gerridae)の群れと繁殖器官に関する予備的研究

概要

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The sea skater Halobates japonicus Esaki was collected at two study sites, NA-1 and MA, in Kabira Bay on Ishigaki Island. Aggregations consisting of both nymphs and adults were found on the sea surface close to the shore often under overhanging coastal vegetation. At NA-1, 67% out of 309 insects caught were adults and the percentage of males was 69%, At MA, 52% of 230 specimens were adults and the percentage of males was 79%. The adults were dissected to count the number of eggs and to measure the length of the long and short axes of a mature egg or a testis. At site NA-1, 53% of the females were gravid with 2-10 mature eggs and 73% of the females had 1-7 semimature eggs. At site MA, 60% of females were gravid with 3-8 mature eggs and 54% of females had 1-4 semi-mature eggs. The mean number of immature eggs per ovaliole was 1.20 at site NA-1 and 1.77 at site MA. The mean size of both the long and short axes of a mature egg was big compared to the body length of the females (about 6mm), measuring 1.51mm and 0.434mm at site NA-1 and 1.54mm and 0.447mm at site MA. The mean length of the long and short axes of the testis was 2.78mm and 0.356mm at site NA, and 2.71mm and 0.341mm at site MA. In testis size, there appeared to be no distinctive differences, which may suggest a difference in sexual maturation among adult males.
盛岡大学の論文
2006-03-30