短时低温胁迫对广聚萤叶甲发育和生殖的影响

广聚萤叶甲Ophraella commnuna 是入侵性杂草豚草Ambrosia artemisiifolia的一种重要专一性天敌.为探明短时低温胁迫对广聚萤叶甲发育和生殖的影响,将广聚萤叶甲置于2,5,8,11和14°C人工气候箱内(RH 70%±5%,14L:10D)处理2 h,测定卵、幼虫、蛹存活率、发育历期及成...

Effects of short-term low temperature stress on the development and fecundity of Ophraella communa LeSage(Coleoptera:Chrysomelidae)

Ophraella communa LeSage (Coleoptera: Chrysomelidae) is an important and specific natural enemy of Ambrosia artemisiifolia L. (Asterales: Asteraceae). To understand the effects of short-term low temperature stress on development and fecundity of O. communa, the survival rates and developmental durations of eggs, larvae and pupae, and survival rate, longevity and fecundity of adults of O. communa under short-term (2 h) low-temperature (2, 5, 8, 11, and 14℃) stresses were determined in five environmental chambers (a relative humidity of 70%±5% and a photoperiod of 14L∶10D). The results showed that the hatch rate of eggs decreased with the decreasing temperature. The hatch rate of eggs was 90.7% at 28℃ (the control), while the lowest hatch rate of eggs (72.2%) was observed in the 2℃-stress treatment. The survival rates of larvae were significantly affected by low-temperature stresses. The larval survival rates were 40.0%, 42.7%, 62.7%, 72.7%, 70.0% and 78.0% in 2℃-, 5℃-, 8℃-, 11℃- and 14℃-stress treatments and the non-stress control, respectively. After 2-14℃ short-term stresses, the survival rates of pupae was 88.0%-92.0%, which did not differ from that of the control (90.7%) (P>0.05). The longevity and fecundity of adults decreased significantly and the survival rate of adult was also significantly affected under low temperature stresses, and the survival rate of adults decreased significantly along with the decreasing temperature. Female and male survival rates were 79.0% and 51.0% after 2℃-stress, respectively. The short-term (2 h) low temperature (2-14℃) stresses had significant effects on different developmental stages of O. communa except the pupal stage. It is so inferred that the rapidly dropping temperature may be one of important factors resulting in a low population level of O. communa in early spring in the field.