Fecundity and oviposition in Mortonagrion hirosei asahina, M. selenion (RIS), Ischnura asiatica (Brauer) and I. senegalensis (Rambur), coexisting in estuarine landscapes of the warm temperate zone of Japan (Zygoptera: Coenagrionidae)

摘要

Adults of the 4 spp., inhabiting an estuarine landscape that includes reed communities and rice paddy fields established on water of varying saline concentration in Mie prefecture, Japan, were studied. The fecundity of Ischnura spp. was higher than that of Mortonagrion spp. I. senegalensis contained the largest number of mature, submature, and immature eggs with the smallest mature egg size, whereas M. selenion contained the smallest number of immature eggs with the largest mature egg size. During a 3-day laboratory oviposition experiment without food, all females developed eggs, resulting in a greater number of mature eggs than was originally contained. Most of the eggs that developed to maturity were laid by M. selenion and I. asiatica, while M. hirosei laid only half of the number laid by either of these. The oviposition process of the 4 spp. is discussed from the viewpoint of their larval habitat selection.