マダニ類の生態学的研究 : 5. フタトゲチマダニとキチマダニの産卵と発育におよぼす湿度の影響

Abstract

The effect of relative humidity on the oviposition and development of Haemaphysalis longicornis and H. flava was studied under laboratory condition at 25℃. Pre-oviposition period of H. longicornis was little influenced by the humidity, while that of H. flava was longer at 90% than at 100% R. H. H. longicornis deposited eggs in all humidities from 100% down to 52%, though the mean egg number per mg body weight reduced with decreasing humidity. No eggs hatched at humidities lower than 68%. Neither egg deposition nor hatching occurred in H. flava at humidities lower than 68%, and the mean egg number was smaller at 90% than at 100%. Engorged larvae of both species were little affected in subsequent development when kept under higher humidities of 100 and 90%, but could not molt below 74%. At 90% R. H. the molting rate was higher in H. longicornis larvae than in H. flava. The nymphs of H. longicornis could molt at all humidities from 100% down to 52%, but the molting rates was reduced as the relative humidity decreased. The nymphs of H. flava could not molt at humidities below 74%. The developmental period of engorged nymphs of H. longicornis gradually prolonged with decreasing humidity, whereas that of H. flava markedly prolonged at 90%, the lowest humidity inducing molt for this species. The longevity of unfed adults and nymphs did not differ between the two species, and was shortened with decreasing humidity. These results suggest that H. flava is less tolerant to low humid conditions than H. longicornis.