关键词: 广聚萤叶甲, 豚草, 低温胁迫, 发育, 繁殖力

Abstract: 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.

Key words: Ophraella communa, Ambrosia artemisiifolia, low temperature stress, development, fecundity