滞育诱导温周期对桃小食心虫滞育幼虫生理指标的影响

Effects of diapause-inducing thermoperiod on the physiological indices of diapause larvae of Carposina sasakii( Lepidoptera: Carposinidae)

【目的】为了明确秋季温度升高对桃小食心虫Carposina sasakii Matsumura耐寒性的影响,针对桃小食心虫滞育过程的生理指标进行了一系列研究。【方法】在GXZ-0450型智能光照培养箱中,温度为26~18,26~20,26~22,28~18,28~20,28~22,30~18,30~20和30~22℃9组变温下（高温10 h,低温14 h,相对湿度70%~80%,光周期为12L∶12D）分别诱导桃小食心虫滞育,再对滞育幼虫过冷却点（supercooling point,SCP）、结冰点（freezing point,FP）以及体内水、脂肪和小分子糖醇类物质含量进行测定。【结果】在适宜滞育的光照下变温不会影响桃小食心虫的滞育率,所有脱果的老熟幼虫全部进入滞育,但其生理指标却有很大差异,其中SCP和FP在较高日高温下较高（SCP：F135,2=23.83,P〈0.001;FP：F135,2=47.64,P〈0.0001）,而在较高夜低温下反而较低（SCP：F135,2=52.88,P〈0.0001;FP：F135,2=33.34,P〈0.0001）。含水量随夜低温和日高温升高显著升高（夜低温：F135,2=13.47,P〈0.0001;日高温：F135,2=10.39,P〈0.0001）。脂肪含量随夜低温升高下降（F135,2=40.91,P〈0.0001）,随日高温升高而上升（F135,2=161.18,P〈0.0001）。小分子糖醇类物质含量随温度的变化各不相同,但差异均显著（P〈0.0001）：其中海藻糖、葡萄糖和赤藓糖醇的含量随夜低温升高而下降,但在日高温30℃时海藻糖和赤藓糖醇的含量却随夜温的升高而升高,葡萄糖的含量随夜低温的变化无差异;甘油随日高温的升高而显著升高,随夜低温的升高而显著下降;山梨醇和肌醇的含量随夜低温和日高温的变化差异很大。【结论】桃小食心虫不同温度下诱导滞育的幼虫SCP、FP、水、脂肪和小分子糖醇类含量存在明显差异。滞育诱导期温度对桃小食心虫幼虫的滞育生理有重要的作用,其滞育幼虫起始生理差别可能会影响其越冬。

【Aim】 To reveal the effects of autumn warming on cold tolerance of the peach fruit moth, Carposina sasakii Matsumura, a series of physiological parameters of larvae of the moth during diapause induction were investigated. 【Methods】 By using climatic chambers, the diapause of larvae of C. sasakii was induced under 9 alternating temperature regimes, i.e., 26-18, 26-20, 26-22, 28-18, 28-20, 28-22, 30-18, 30-20 and 30-22℃ （10 h high temperature, 14 h low temperature, RH 70%-80%, photoperiod 12L∶12D）. The supercooling point （SCP）, freezing point （FP）, and the contents of water, fat and small molecular sugar alcohols in diapause larvae were investigated. 【Results】 The alternating temperature had no effect on diapause rates of larvaeunder suitable photoperiods, and all mature larvae from the fruit entered diapause. SCP and FP increased with daytime temperature increasing （SCP： F135, 2=23.83, P〈0.001; FP： F135, 2=47.64, P〈0.0001）, and decreased significantly with the increase of nighttime temperature （SCP： F135, 2=52.88,P〈0.0001; FP： F135, 2=33.34, P〈0.0001）. Water contents increased with nighttime and daytime temperature increasing （nighttime： F135,2=13.47, P〈0.0001; daytime： F135, 2=10.39,P〈0.0001）, whereas the contents of fat decreased with nighttime increasing （F135, 2=40.91, P〈0.0001） and increased with the increase of daytime temperature （F135, 2=161.18, P〈0.0001）. Contents of small molecular sugar alcohols varied with temperature （P〈0.0001）. The contents of trehalose, glucose and erythritol decreased with nighttime temperature increasing, but the contents of trehalose and erythritol increased with nighttime temperature increasing at daytime temperature 30℃, and the contents of glucose were not different. The glycerol contents increased with daytime temperature increasing and decreased with nighttime temperature increasing. The inositol and sorbitol contents were rotably different at different daytime or nighttime temperatures. 【Conclusion】 The SCP, FP, and the contents of water, fat and small molecular sugar alcohols in diapause larvae of C. sasakii are different at different diapause induction temperature. Diapause induction temperature plays an important role in diapause physiology of C. sasakii, and the initial physiological differences of diapause larvae may affect their overwintering.