Abstract
The development, survival and oviposition of I. ovatus were observed at various temperatures (15,17,20,25,27 and 30℃) in the laboratory. Oviposition occurred at 17 to 30℃, but the mean number of deposited eggs per mg body weight of engorged female was markedly reduced at 30℃. The periods of preoviposition and oviposition were shortened as the temperature rose, except at 30℃. The egg hatchability was as high as 83-93% at 17-25℃, and was low at both higher (27-30℃) and lower (15℃) temperatures. The incubation period of eggs was shortened with increasing temperature. Engorged larvae and nymphs molted at 15 to 30℃, but the molting percentage was small at 30℃ in larvae, and at 15,20 and 30℃ in nymphs. The developmental zeroes for oviposition and eggs were 8.2 and 6.4℃, respectively. The developmental periods of engorged larvae and nymphs were generally shortened as the temperature rose, but temperature and the duration of development did not show a clear linear relationship. I. ovatus is less tolerant to low and high temperatures than the common Japanese haemaphysalids, Haemaphysalis longicornis and H. flava. This might be a factor that restricts the habitat of I. ovatus.
