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
Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity a...Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity and the economy. It is unclear why some species can become successful invaders, whereas most （even if closely related） remain noninvasive. We previously proposed a hypothesis that parasites associated with invading species can promote their invasive success if they are harmless toward the invaders but harmful to their competitors and/or predators in the newly colonized habitat. Here we discuss whether microsporidia that have recently been discovered in the invasive ladybird Harmonia axyridis contribute to its invasive success. We show that all H. axyridis beetles sourced from diverse collection sites all over the world carry abundant microsporidia. This suggests that both native and invasive H. axyridis populations are associated with these tolerated parasites, which were likely to have existed in native populations before expansion rather than being acquired in newly colonized areas. We describe the pathogenesis of the microsporidia during different developmental stages of H. axyridis and we address the possibility that the predation of its infected eggs and larvae by competing native ladybird species may lead to their infection and ultimately to their decline. Finally, we discuss our initial hypothesis： microsporidia that are tolerated by an invasive vector insect can be active against susceptible native competitors and/or predator species.展开更多
Influence of temperature on certain biological attributes of an aphidophagous ladybeetle, Coccinella septempunctata Linnaeus, feeding on mustard aphid, Lipaphis erysimi (Kaltenbach), at five different temperatures, vi...Influence of temperature on certain biological attributes of an aphidophagous ladybeetle, Coccinella septempunctata Linnaeus, feeding on mustard aphid, Lipaphis erysimi (Kaltenbach), at five different temperatures, viz. 20, 25, 27, 30 and 35℃ was investigated. Its developmental period was shortest (11.7±0.09days) at 35℃ and longest (20.6±0.35 days) at 20℃. Developmental rate increased with increase in temperature. Hatching percent, larval survival, adult emergence and growth index were maximum at 30℃ and minimumat 20℃. Oviposition period and fecundity were highest at 30℃ and lowest at 20℃. A positive linear relationship exists between temperature and developmental rate and negative correlation between the duration of immature life stages and temperature. The proportion of developmental period allocated to each immature stage was found to be similar at each temperature regime. Thus, 30℃ was found as the most suitable for C. septempunctata amongst the five temperatures tested.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Invasive species are characterized by the rapid growth and spread of their populations after establishing a foothold in new habitats, and there are now many examples of such species negatively affecting biodiversity and the economy. It is unclear why some species can become successful invaders, whereas most （even if closely related） remain noninvasive. We previously proposed a hypothesis that parasites associated with invading species can promote their invasive success if they are harmless toward the invaders but harmful to their competitors and/or predators in the newly colonized habitat. Here we discuss whether microsporidia that have recently been discovered in the invasive ladybird Harmonia axyridis contribute to its invasive success. We show that all H. axyridis beetles sourced from diverse collection sites all over the world carry abundant microsporidia. This suggests that both native and invasive H. axyridis populations are associated with these tolerated parasites, which were likely to have existed in native populations before expansion rather than being acquired in newly colonized areas. We describe the pathogenesis of the microsporidia during different developmental stages of H. axyridis and we address the possibility that the predation of its infected eggs and larvae by competing native ladybird species may lead to their infection and ultimately to their decline. Finally, we discuss our initial hypothesis： microsporidia that are tolerated by an invasive vector insect can be active against susceptible native competitors and/or predator species.
文摘Influence of temperature on certain biological attributes of an aphidophagous ladybeetle, Coccinella septempunctata Linnaeus, feeding on mustard aphid, Lipaphis erysimi (Kaltenbach), at five different temperatures, viz. 20, 25, 27, 30 and 35℃ was investigated. Its developmental period was shortest (11.7±0.09days) at 35℃ and longest (20.6±0.35 days) at 20℃. Developmental rate increased with increase in temperature. Hatching percent, larval survival, adult emergence and growth index were maximum at 30℃ and minimumat 20℃. Oviposition period and fecundity were highest at 30℃ and lowest at 20℃. A positive linear relationship exists between temperature and developmental rate and negative correlation between the duration of immature life stages and temperature. The proportion of developmental period allocated to each immature stage was found to be similar at each temperature regime. Thus, 30℃ was found as the most suitable for C. septempunctata amongst the five temperatures tested.
