Objective Effects of short-term high-temperature exposure on survival and reproduction of adult Assara inouei Yamanaka were studied to determine the thermal adaptation of the insect for population control.
Method Within 12 h of emergence, adult A. inouei were exposed to 25℃ (CK), 35℃, 38℃, or 41℃ for 1 h, 2 h, 4 h, or 6 h, then moved to a 25°C chamber for feeding and observation. The survival rate, lifespan, fecundity, and egg hatching rate of the insects were monitored.
Result Both temperature and duration of the exposures significantly affected the survival and reproduction of A. inouei. The increased temperature and prolonged exposure caused a gradual decline on the survival rate, lifespan, and oviposition of the insects. The average number of eggs laid per female and that at the peak egg-laying period decreased gradually, and the egg hatching rate decreased as well. But the pre-oviposition period was not significantly altered. Exposure to 35°C for 1 h and 2 h did not cause significant differences on the survival rate, lifespan, pre-oviposition period or egg hatching rate, as compared to CK. But it significantly affected the female oviposition period and average number of eggs laid per individual insect. On the other hand, after being exposed to 41°C for 4 h or 6 h, the insects sustained a significantly lower survival rate, lifespan, pre-oviposition and oviposition periods, number of eggs laid per female, and egg hatching rate than those of CK.
Conclusion Exposure to a rising temperature up to 41°C in a duration of 4 h to 6 h could be significantly detrimental to the survival and fecundity of adult A. inouei.
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