温度对新菠萝灰粉蚧生长发育和繁殖的影响

新菠萝灰粉蚧是近年在我国新发现的一种重要外来入侵害虫,温度是决定新菠萝灰粉蚧能否建立稳定种群的最基本因素.本研究以南瓜作为寄主,探索恒温条件对新菠萝灰粉蚧生长发育和繁殖的影响.在17、20、23、26、29和32 ℃,光周期14L∶10D,相对湿度(75±5)%的实验室条件下,测定了新菠萝灰粉蚧各虫态的发育历期、发育速率、存活率和繁殖力,组建了新菠萝灰粉蚧的实验种群生命表.结果表明: 在20～29 ℃,各虫态的发育历期均随温度的升高而缩短,在20 ℃下雌、雄若虫期的发育历期最长,分别为46.95和50.26 d;29 ℃时雌虫若虫期的发育历期最短,为20.28 d;而雄虫若虫期在32 ℃时最短,为20.70 d.各虫态的温度与发育速率的关系均符合二次回归关系.此外,温度显著影响新菠萝灰粉蚧的存活率,在29 ℃时雌、雄若虫期的存活率均最高,分别为70.3%和69.3%;雌虫世代的发育起点温度为13.80 ℃,有效积温为491.50日·度;雄虫世代的发育起点温度为11.61 ℃,有效积温为388.85日·度.新菠萝灰粉蚧的产卵前期和成虫寿命随着温度的升高而缩短;成虫产卵量在29 ℃时最高,达每雌442.2粒;最小为20 ℃,仅为每雌111.8粒;29和20 ℃下种群趋势指数分别为168.2和19.1,且在17和32 ℃时,新菠萝灰粉蚧1龄若虫和3龄若虫均表现为生长停滞.说明温度过高或过低均不利于其生长发育.温度对新菠萝灰粉蚧的生长发育、存活、繁殖及种群增长有显著的影响,23～29 ℃是最适宜新菠萝灰粉蚧生长发育和繁殖的温度范围.

Effects of temperature on the growth,development and reproduction of Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudococcidae).

In recent years, Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudococcidae) is found as one of important alien species in China. For the alien pest, temperature always is a crucial factor on constructing stable population. In this study, the development and reproduction of D. neobrevipes population of pumpkin under different temperatures were investigated. The developmental duration, developmental rate, survival rate and fecundity of D. neobrevipes were compared in the laboratory under the conditions of 17, 20, 23, 26, 29 and 32 ℃, photoperiod 14L∶10D, RH (75±5)%, and the life table of the laboratory population was constructed. The results showed that in 20-29 ℃, the developmental durations of every stage of D. neobrevipes all decreased with the increasing temperature; under 20 ℃, both female and male nymph D. neobrevipes had the longest duration, being 46.95 and 50.26 d, respectively. The female and male nymph D. neobrevipes grew most fast under 29 ℃ (20.28 d) and 32 ℃ (20.70 d). The relationship between the developmental rate and temperature for each stage could be simulated by the quadratic regression. In addition, we found that the temperature could impact the survival rate of D. neobrevipes. The highest survival rate of D. neobrevipes was recorded at 29 ℃ for both female (70.3%) and male (69.3%) nymphs. The developmental threshold temperature of female and male was 13.80 ℃ and 11.61 ℃, and the accumulated temperature of female and male was 491.50 and 388.85 day-degrees, respectively. Both pre-oviposition duration and adult longevity decreased with increasing temperature, and the highest fecundity per female was 442.2 eggs at 29 ℃, and the lowest 111.8 eggs at 20 ℃. The population trend indexes under 20 ℃ and 29 ℃ were 19.1 and 168.2, respectively. At 17 ℃ and 32 ℃, D. neobrevipes of the 1st instar nymphs and 3rd instar nymphs were found to stop growth, suggesting that excessively high or low temperature was unfavorable to the growth of D. neobrevipes. In conclusion, temperature could significantly affect the growth and development, survivorship, reproduction and population increasing of D. neobrevipes, and the most suitable temperature range for this pest is from 23 ℃ to 29 ℃.