Ophraella communa(Coleoptera: Chrysomelidae), the ragweed leaf beetle, is a biological control agent of the invasive common ragweed, Ambrosia artemisiifolia(Asterales: Asteraceae). Adults can survive cold conditions t...Ophraella communa(Coleoptera: Chrysomelidae), the ragweed leaf beetle, is a biological control agent of the invasive common ragweed, Ambrosia artemisiifolia(Asterales: Asteraceae). Adults can survive cold conditions that occur during winter. The adults mate before entering overwintering. Understanding the connection between copulation and overwintering will be useful for determining O. communa seasonality. Determining the relationship between overwintering and copulation required comparison of mated and unmated beetles at mean lethal temperature(LTemp_(50)) exposures for 2 h. Cold-related physiological indices, including the water ratio, super cooling point(SCP), cryoprotectant levels, and energy reserve levels, were also measured. Mating treatment decreased the LTemp_(50) of both sexes by reducing their mean SCP and water ratios. Although the changes of cryoprotectant levels in mated adults were not precisely consistent in between the genders, they increased greatly in both males and females. Body sugar may play a role in copulation and may also elevate cold hardiness in O. communa.展开更多
To investigate the seasonal adaptation strategies of Ophraella communa to new habitats, the effects and regulation mechanisms of photoperiod and temperature on the reproductive diapause in a population collected from ...To investigate the seasonal adaptation strategies of Ophraella communa to new habitats, the effects and regulation mechanisms of photoperiod and temperature on the reproductive diapause in a population collected from Changsha, Hunan were examined. Adults showed obvious reproductive diapause, which was regulated by photoperiod and temperature. At 30~C, there was no adult diapause occurring under either long-day or short-day conditions; at 25~C the pre-oviposition period was short and fecundity was high in adult females under L ： D 16 ： 8 h, whereas under L ： D 12 ： 12 h, a few females entered reproductive diapause; at 20~C under short-day conditions, all female adults entered diapause. The pre-oviposition period was significantly prolonged when the pupae and adults were transferred from long-days to short-days, but the day length influence was not obvious when they were transferred only in the adult stage. However, the fecundity dropped greatly no matter whether the photoperiod shifted to short-days only in the adult stage or whether the shift occurred in both the pupal and adult stage. The fecundity was extremely low when photoperiod shifted from long-days to short-days in both pupal and adult stages. This was an indication that the pupal and adult stages were the photoperiod-sensitive stage for adult reproductive diapause. This was especially true for the photoperiod in the pupal stage, which has a distinctly significant regulative effect on reproductive diapause. Additionally, this article also addresses the reason for different photoperiodic response patterns in reproductive diapause induction between the Changsha strain and the Tsukuba strain （Japan） of O. communa.展开更多
基金supported by the National Natural Science Foundation of China(31322046)
文摘Ophraella communa(Coleoptera: Chrysomelidae), the ragweed leaf beetle, is a biological control agent of the invasive common ragweed, Ambrosia artemisiifolia(Asterales: Asteraceae). Adults can survive cold conditions that occur during winter. The adults mate before entering overwintering. Understanding the connection between copulation and overwintering will be useful for determining O. communa seasonality. Determining the relationship between overwintering and copulation required comparison of mated and unmated beetles at mean lethal temperature(LTemp_(50)) exposures for 2 h. Cold-related physiological indices, including the water ratio, super cooling point(SCP), cryoprotectant levels, and energy reserve levels, were also measured. Mating treatment decreased the LTemp_(50) of both sexes by reducing their mean SCP and water ratios. Although the changes of cryoprotectant levels in mated adults were not precisely consistent in between the genders, they increased greatly in both males and females. Body sugar may play a role in copulation and may also elevate cold hardiness in O. communa.
文摘To investigate the seasonal adaptation strategies of Ophraella communa to new habitats, the effects and regulation mechanisms of photoperiod and temperature on the reproductive diapause in a population collected from Changsha, Hunan were examined. Adults showed obvious reproductive diapause, which was regulated by photoperiod and temperature. At 30~C, there was no adult diapause occurring under either long-day or short-day conditions; at 25~C the pre-oviposition period was short and fecundity was high in adult females under L ： D 16 ： 8 h, whereas under L ： D 12 ： 12 h, a few females entered reproductive diapause; at 20~C under short-day conditions, all female adults entered diapause. The pre-oviposition period was significantly prolonged when the pupae and adults were transferred from long-days to short-days, but the day length influence was not obvious when they were transferred only in the adult stage. However, the fecundity dropped greatly no matter whether the photoperiod shifted to short-days only in the adult stage or whether the shift occurred in both the pupal and adult stage. The fecundity was extremely low when photoperiod shifted from long-days to short-days in both pupal and adult stages. This was an indication that the pupal and adult stages were the photoperiod-sensitive stage for adult reproductive diapause. This was especially true for the photoperiod in the pupal stage, which has a distinctly significant regulative effect on reproductive diapause. Additionally, this article also addresses the reason for different photoperiodic response patterns in reproductive diapause induction between the Changsha strain and the Tsukuba strain （Japan） of O. communa.
