温湿度对松毛虫赤眼蜂种群增长的影响

THE INFLUENCE OF TEMPERATURE AND HUMIDITY ON THE POPULATION INCREASE OF TRICHOGRAMMA DENDROUMI

在13—33℃、35％—95％R.H.范围内的7个恒温、13个温湿度组合下,测定了松毛虫赤眼蜂(Trichogramma dendrolimi Matsumura)的发育、存活和生殖情况。结果表明,该蜂在13—30℃(75％R.H.)范围内,卵至羽化的发育速率与温度呈逻辑斯蒂曲线关系;发育起点温度为10.1±0.03℃,有效积温常数为140.2±0.29日度;幼期存活率在26℃左右最高;成虫寿命随温度升高而缩短,生殖力以23—28℃最高;内禀增长力(r_m)随温度升高而增大,28℃时达最大,随后急剧下降,至31℃时巳为负值。低湿和高湿在低温下有使发育速率减缓,而在适温和高温下则有使发育速率加快的趋势;低温低湿和高温高湿有使幼期存活率下降的趋势;在低温、高温下,75％R.H.对成虫存活、生殖最有利,95％R.H.次之;在适温下湿度对生殖力无影响,成虫寿命在低湿下最短。33℃下,3种湿度下均未产生雌性后代。

The development,survival and reproduction of the egg parasite Trichogramma dendroli-mi Matsumura, collected from the eggs of the pine moth Dendrolimus punctatus (Walker), and reared on Corcyra cephalonica (Stainton), were determined under 13 temperature and humidity regimes. The relationship between the development rate of the parasite from egg to adult emergence and temperatute from 13℃ to 30℃ with 75% RH fitted to the logistic curve. The development threshold temperature and thermal constant for the whole immature stage were estimated to be 10.1±0. 03℃ and 140. 2±0. 29 day degrees, respectively. The survival rate of the immature stage was highest under about 26℃. Longevity of the female wasp decreased with increase in temperature. The fecundity was highest at the range 23-28℃. With increasing temperature, the intrinsic rate of increase increased until 28℃, then declined sharply,and reached zero at about 31 ℃. Both low and high levels of relative humidity showed decelerative effect under low temperature and accelerative effect under high temperature on rate of development. The survival rate of the immature stage was reduced under the combinations of low temperature and high humidity or high temperature and high humidity. Under both low and high temperatures, adult survivorship and fertility were higher under 75%RH than those under lower and higher levels of relative humidity. Under 26 ℃, changes in relative humidity did not affect fertility, but adult longevity was reduced at the lower level of relative humidity. At 33℃,no female progeny were produced at all levels of relative humidity tested.