宽翅曲背蝗卵的过冷却能力与抗寒性

Supercooling capacity and cold hardiness of the Pararcyplera microptera meridionalis( Orthoptera: Acrididae) eggs

采用热电偶法,在室内测定了宽翅曲背蝗卵的过冷却能力及抗寒性.结果表明:土壤含水量对滞育前卵的含水量有显著影响,而对卵过冷却点(SCP)的影响不显著,卵含水量随着土壤含水量的升高而上升.不同发育时期卵的SCP、含水量和脂肪含量存在显著差异.随着卵的发育,其含水量从产卵当天的51.5%下降至120 d的46.8%,脂肪含量从10.5%(鲜质量)/19.0%(干质量)上升到14.5%(鲜质量)/28.9%(干质量),而SCP从-23.5℃下降至-30.0℃;卵SCP与其含水量及脂肪含量存在显著相关关系;深度滞育卵的SCP显著低于滞育前和滞育初期卵的SCP.不同低温强度和处理时间对滞育卵的存活率有显著影响.滞育卵暴露12 h的致死温度为-27.3℃,在-25℃低温处理的致死时间为22.73 d.滞育卵的SCP与致死温度相近,说明宽翅曲背蝗卵为不耐结冰类型,且SCP是衡量其抗寒性的可靠指标.

Using the thermocouple method, the supercooling point （SCP） and cold hardiness of Pararcyplera microptera meridionalis eggs were measured in the laboratory. The soil water content significantly affected the water content of pre-diapause eggs, but had no significant effect on the SCP, and the water content of pre-diapause eggs rose with the increasing soil water content. There were highly significant differences among the SCPs, water contents or fat contents in the eggs at dif- ferent developmental stages. With the egg＇ s development, the water content decreased from 51.5 % at oviposition to 46.8% in 120 days after oviposition, the fat content increased from 10.5% （fresh mass）/19.0% （dry mass） to 14.5% （fresh mass）/28.9% （dry mass）, and the SCP declined from -23.5 ~C to -30.0 %. There was a significant correlation between the SCP and the water content or fat content. The SCPs of deep-diapause eggs were lower than those of pre- and early- diapause eggs. The different low temperatures and treatment durations significantly affected the sur- vival rate of diapause eggs. The lethal low temperature （ LtempS0 ） for 12 h exposure was -27.3℃ and the lethal time （Ztime50） at -25℃ was 22.73 days. As the mean SCPs of diapause eggs was much similar to their ZtcmpS0, the SCP could be considered as a good indicator of cold hardiness for P. m. meridionalis eggs and this species is a freeze-intolerant insect.