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
Development, survival and reproductive performance of coexisting ladybird species, viz. Cheilomenes sexmaculata, Coccinella septempunctata, and Coccinella transversalis, of the tribe Coccinellini were studied and comp...Development, survival and reproductive performance of coexisting ladybird species, viz. Cheilomenes sexmaculata, Coccinella septempunctata, and Coccinella transversalis, of the tribe Coccinellini were studied and compared to assess their coexistence and ecological relationships. High values of life history parameters, viz. developmental rate,immature survival, fecundity, egg viability, reproductive rate and conversion of efficiency of ingested food were recorded for C. sexmaculata followed by C. transversalis and C.septempunctata suggesting that the former has intrinsic advantages over the latter two species. This could possibly counterbalance its disadvantages, like relatively smaller size and weight, thereby making it competitive. The developmental period increased with increase in body size. Exceptionally high fecundity after single mating has been recorded in C. sexmaculata. The egg viability, however, was lower than in both Coccinella species.展开更多
Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reare...Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reared for five generations in laboratory derived differential nutrition from five food sources (i.e. aphid species, Rhopalosiphum maidis (Fitch), Aphis craccivora Koch, Aphis gossypii Glover, Uroleucon compositae (Theobald) and Lipaphis erysimi (Kalt.)). The order of relative prey suitability was A. gossypii, A. craccivora, R. maidis, U. compositae and L.erysimi. Neonates suffered maximum mortality followed by eggs. Estimates of net reproductive rate,intrinsic rate of increase and finite rate of increase were highest (407.18, 0.2274 day^-1, 1.2553 day^-1) on A. gossypii and lowest (176.02, 0.1533 day^-1, 1.1657 day^-1) on L. erysimi. Generation time was shortest (26.43 days) on A. gossypii and longest (33.73 days) on L. erysimi. The present study thus,provides an explanation to the high incidence of P. dissecta on A. gossypii, as it experienced high intrinsic rate of increase and optimal values for related demographic parameters.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Development, survival and reproductive performance of coexisting ladybird species, viz. Cheilomenes sexmaculata, Coccinella septempunctata, and Coccinella transversalis, of the tribe Coccinellini were studied and compared to assess their coexistence and ecological relationships. High values of life history parameters, viz. developmental rate,immature survival, fecundity, egg viability, reproductive rate and conversion of efficiency of ingested food were recorded for C. sexmaculata followed by C. transversalis and C.septempunctata suggesting that the former has intrinsic advantages over the latter two species. This could possibly counterbalance its disadvantages, like relatively smaller size and weight, thereby making it competitive. The developmental period increased with increase in body size. Exceptionally high fecundity after single mating has been recorded in C. sexmaculata. The egg viability, however, was lower than in both Coccinella species.
文摘Prey driven demographic parameters of an aphidophagous ladybird, Propylea dissecta (Mulsant) were studied in attempt to answer how ladybird overcomes the problem of seasonally fluctuating food base. The ladybird reared for five generations in laboratory derived differential nutrition from five food sources (i.e. aphid species, Rhopalosiphum maidis (Fitch), Aphis craccivora Koch, Aphis gossypii Glover, Uroleucon compositae (Theobald) and Lipaphis erysimi (Kalt.)). The order of relative prey suitability was A. gossypii, A. craccivora, R. maidis, U. compositae and L.erysimi. Neonates suffered maximum mortality followed by eggs. Estimates of net reproductive rate,intrinsic rate of increase and finite rate of increase were highest (407.18, 0.2274 day^-1, 1.2553 day^-1) on A. gossypii and lowest (176.02, 0.1533 day^-1, 1.1657 day^-1) on L. erysimi. Generation time was shortest (26.43 days) on A. gossypii and longest (33.73 days) on L. erysimi. The present study thus,provides an explanation to the high incidence of P. dissecta on A. gossypii, as it experienced high intrinsic rate of increase and optimal values for related demographic parameters.
