To understand the adaptive strategies of the overwintering adults of Steno- catantops splendens, the mechanism of maintenance and termination of the reproductive diapause, the variation in mortality between overwinter...To understand the adaptive strategies of the overwintering adults of Steno- catantops splendens, the mechanism of maintenance and termination of the reproductive diapause, the variation in mortality between overwintering females and males, and the mating strategy of the males were investigated. The results indicated that the adult repro- ductive diapause in natural conditions was mainly regulated by photoperiod in the fall - long photoperiods promoted reproductive development and short photoperiods maintained reproductive diapause, and the sensitivity of the overwintering adults to photoperiod was over before the end of the winter. When transferred from natural conditions to controlled laboratory conditions on dates from September through February, pre-oviposition became increasingly shorter with increasingly deferred transfer dates regardless of photoperiod conditions. The adults treated with low temperature for 30 days in September through November had significantly shorter pre-oviposition, suggesting that low temperatures in winter had an important role in the termination of reproductive diapause. The female had a significantly lower supercooling point than the male, which was related to their lower mortality after winter. In addition, observations of wild populations of the species indicated that mating behavior prior to winter and the duration of pre-mating period were not affected by photoperiod; mating and sperm transfer were mostly completed by November. Compared with females only mating before winter, females mating in the spring had shorter life span, longer pre-oviposition, lower hatching rate and laid fewer egg pods while showing no significant difference with regard to ovipositional interval, per pod number of eggs and nymph dry weight.展开更多
In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facult...In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facultative diapause and prepares diapause can provide us new insights to study developmental and evolutionary biology.It has been shown that the circadian clock genes can participate in photoperiodic measurement and regulate reproductive diapause initiation through JH signaling in short-day-induced winter diapause.However,how circadian clock genes translate photoperiodic information into downstream JH signaling for diapause destiny and then affect diapause preparation remains largely unknown.In the present study,we investigate this in the cabbage beetle Colaphellus bowringi which undergoes reproductive diapause under long-day condition.We respectively knocked down two circadian clock negative regulators,period(per)and timeless(tim),in the 3-day-old larvae(most sensitive to photoperiod),and dsgfp treatment was served as a control.Under the diapause-inducing photoperiod(16L:8D),knocking down per and tim significantly decreased the rate of burrowing behavior.And mtany female beetles of the per and tim RNAi showed developed ovary,decreased lipid accumulation and downregulated expression of stress resistance genes.The JHinduced genes,Kr-h1,JHE1,Vg1,and Vg2, significantly increased in the females with suppression of per and tim.It implied that suppression of per and tim during diapause initiation phase(DIP)could activate the JH signaling in the female adults.Before the beetles enter into diapause preparation phase(DPP),we used RNA sequencing to analyize gene expression profiles after per and tim RNAi.It showed that many differentially expressed genes were enriched in environmental information processing,such as mTOR and TGF-beta signaling pathway.To ask whether per and tim also regulate diapause preparation,we knocked down these two genes in the female adults during DPP.It showed that the diapause destiny was n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
文摘To understand the adaptive strategies of the overwintering adults of Steno- catantops splendens, the mechanism of maintenance and termination of the reproductive diapause, the variation in mortality between overwintering females and males, and the mating strategy of the males were investigated. The results indicated that the adult repro- ductive diapause in natural conditions was mainly regulated by photoperiod in the fall - long photoperiods promoted reproductive development and short photoperiods maintained reproductive diapause, and the sensitivity of the overwintering adults to photoperiod was over before the end of the winter. When transferred from natural conditions to controlled laboratory conditions on dates from September through February, pre-oviposition became increasingly shorter with increasingly deferred transfer dates regardless of photoperiod conditions. The adults treated with low temperature for 30 days in September through November had significantly shorter pre-oviposition, suggesting that low temperatures in winter had an important role in the termination of reproductive diapause. The female had a significantly lower supercooling point than the male, which was related to their lower mortality after winter. In addition, observations of wild populations of the species indicated that mating behavior prior to winter and the duration of pre-mating period were not affected by photoperiod; mating and sperm transfer were mostly completed by November. Compared with females only mating before winter, females mating in the spring had shorter life span, longer pre-oviposition, lower hatching rate and laid fewer egg pods while showing no significant difference with regard to ovipositional interval, per pod number of eggs and nymph dry weight.
基金Funded by the National Natural Science Foundation of China(31701842)
文摘In insects,facultative diapause is a state of developmental arrest mainly induced by photoperiod or temperature that allows insects to survive adverse environmental conditions.Understanding how insect initiates facultative diapause and prepares diapause can provide us new insights to study developmental and evolutionary biology.It has been shown that the circadian clock genes can participate in photoperiodic measurement and regulate reproductive diapause initiation through JH signaling in short-day-induced winter diapause.However,how circadian clock genes translate photoperiodic information into downstream JH signaling for diapause destiny and then affect diapause preparation remains largely unknown.In the present study,we investigate this in the cabbage beetle Colaphellus bowringi which undergoes reproductive diapause under long-day condition.We respectively knocked down two circadian clock negative regulators,period(per)and timeless(tim),in the 3-day-old larvae(most sensitive to photoperiod),and dsgfp treatment was served as a control.Under the diapause-inducing photoperiod(16L:8D),knocking down per and tim significantly decreased the rate of burrowing behavior.And mtany female beetles of the per and tim RNAi showed developed ovary,decreased lipid accumulation and downregulated expression of stress resistance genes.The JHinduced genes,Kr-h1,JHE1,Vg1,and Vg2, significantly increased in the females with suppression of per and tim.It implied that suppression of per and tim during diapause initiation phase(DIP)could activate the JH signaling in the female adults.Before the beetles enter into diapause preparation phase(DPP),we used RNA sequencing to analyize gene expression profiles after per and tim RNAi.It showed that many differentially expressed genes were enriched in environmental information processing,such as mTOR and TGF-beta signaling pathway.To ask whether per and tim also regulate diapause preparation,we knocked down these two genes in the female adults during DPP.It showed that the diapause destiny was n
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.
