The mating behavior of Propylea dissecta (Mulsant) was investigated in detail.Protandry was evident, as males mature earlier than females. Predicted age of sexual maturation of male and female ladybirds was 7.12 and 9...The mating behavior of Propylea dissecta (Mulsant) was investigated in detail.Protandry was evident, as males mature earlier than females. Predicted age of sexual maturation of male and female ladybirds was 7.12 and 9.33 days, respectively. Males performed courtship in six steps, viz. approach, watch, examine, embrace, mount and attempt. Embrace is possibly an appeasement act, while examine serves to recognize mate.Chemical signals initiate male attraction toward females. Visual and tactile cues appear to secondarily help in mate recognition. Mating lasted longest (275.40 ± 12.23 min) when it occurred between unmated individuals. It was much shorter (176.60 ± 5.60 min) when prior mated individuals copulated. There was a significant decrease in mating durations when adults were subjected to five successive matings. Fecundity and percent egg viability increased significantly with increase in the number of matings.展开更多
The effects of environmental parameters on insect development have been studied extensively. But the reasons for 2 differential developmental rates within same cohort under varying environmental factors have not been ...The effects of environmental parameters on insect development have been studied extensively. But the reasons for 2 differential developmental rates within same cohort under varying environmental factors have not been explored. For the purpose, in this study the existence and stability of slow and fast development under 5 photoperiods （i.e., 8L： 16D, 10L ： 14D, 12L ： 12D, 14L ： 10D and 16L ： 8D; light and dark hours per day） and its effect on body mass and reproductive attributes in 2 aphidophagous ladybirds, Menochilus sexmaculatus （Fabricius） and Propylea dissecta （Mulsant） was examined on Aphis craccivora Koch at 27 4- 1 ~C temperature. A clear bimodal （2 peaks, where the first peak represented the fast developing and the 2nd peak slow developing individuals） pattern of distribution at each photoperiod was found. The proportion of slow and fast developing individuals in a cohort differed with photoperiods. The slow developing individuals were more in numbers at 8L ： 16D, in equal numbers at 14L ： 10D and in less numbers at 16L： 8D, indicating that the variation in emergence was owing to exogenous cues influenced differential rates of mortality. Slow developing individuals had female biased sex ratio, higher longevity and lower body mass than fast developing individuals. Fast developing females laid higher numbers of eggs with higher egg viability than slow developing females. Study of such variations in development at different photoperiods is helpful to understand its role in the development of insects particularly ladybirds and permits the selection of fast developing bioagents for their use in biocontrol of pest species.展开更多
文摘The mating behavior of Propylea dissecta (Mulsant) was investigated in detail.Protandry was evident, as males mature earlier than females. Predicted age of sexual maturation of male and female ladybirds was 7.12 and 9.33 days, respectively. Males performed courtship in six steps, viz. approach, watch, examine, embrace, mount and attempt. Embrace is possibly an appeasement act, while examine serves to recognize mate.Chemical signals initiate male attraction toward females. Visual and tactile cues appear to secondarily help in mate recognition. Mating lasted longest (275.40 ± 12.23 min) when it occurred between unmated individuals. It was much shorter (176.60 ± 5.60 min) when prior mated individuals copulated. There was a significant decrease in mating durations when adults were subjected to five successive matings. Fecundity and percent egg viability increased significantly with increase in the number of matings.
文摘The effects of environmental parameters on insect development have been studied extensively. But the reasons for 2 differential developmental rates within same cohort under varying environmental factors have not been explored. For the purpose, in this study the existence and stability of slow and fast development under 5 photoperiods （i.e., 8L： 16D, 10L ： 14D, 12L ： 12D, 14L ： 10D and 16L ： 8D; light and dark hours per day） and its effect on body mass and reproductive attributes in 2 aphidophagous ladybirds, Menochilus sexmaculatus （Fabricius） and Propylea dissecta （Mulsant） was examined on Aphis craccivora Koch at 27 4- 1 ~C temperature. A clear bimodal （2 peaks, where the first peak represented the fast developing and the 2nd peak slow developing individuals） pattern of distribution at each photoperiod was found. The proportion of slow and fast developing individuals in a cohort differed with photoperiods. The slow developing individuals were more in numbers at 8L ： 16D, in equal numbers at 14L ： 10D and in less numbers at 16L： 8D, indicating that the variation in emergence was owing to exogenous cues influenced differential rates of mortality. Slow developing individuals had female biased sex ratio, higher longevity and lower body mass than fast developing individuals. Fast developing females laid higher numbers of eggs with higher egg viability than slow developing females. Study of such variations in development at different photoperiods is helpful to understand its role in the development of insects particularly ladybirds and permits the selection of fast developing bioagents for their use in biocontrol of pest species.
