Larvae of aphidophagous ladybirds attack vulnerable stages, such as eggs of conspecific and heterospecific species during prey scarcity, especially when the aphid colony is declining. We investigated food-preference of all four larval instars of ladybirds, viz. Propylea dissecta (Mulsant), Menochilus sexmaculatus (Fabricius) and Coccinella septempunctata Linnaeus, towards various egg-diets and the influence of different monotypic egg-diets on the consumption rate, growth-rate, conversion efficiency, mortality, bodyweight and development. All larval instars of P. dissecta and M. sexmaculatus preferred egg-cannibalism over IGP, while lower instars of C. septempunctata showed no preference and its higher instars preferred vice-versa. The three species developed successfully on monotypic conspecific and heterospecific egg-diets. However, instars developed faster into heavier life stages with lesser mortality when fed on conspecific eggs. The fourth instars of the three-ladybird species had higher consumption rates and conversion efficiencies, while the first instars had higher growth rates than other instars. These parameters were optimal when instars fed on aphids, while conspecific eggs were better diets than heterospecific eggs. The consumption rates of C. septempunctata were higher than the other two ladybird species, however it lagged behind the two in terms of growth rates and conversion efficiencies. The overall mortality was lowest when instars of three ladybirds were fed on aphids followed by conspecific eggs and heterospecific eggs. We also conclude that C. septempunctata eggs may be less palatable to both conspecifics and heterospecific predators and latter ensure survival by refraining intraguild predation and not risking their fitness.

蚜虫的幼虫在猎物稀缺期间攻击脆弱的阶段，例如同种和异种物种的卵，特别是当蚜虫种群减少时。我们调查了瓢虫所有四个幼虫的食物偏好，即。Propylea dissecta (Mulsant) , Menochilus sexmaculatus (Fabricius) 和Coccinella septempunctata Linnaeus, 对各种蛋日粮以及不同单型蛋日粮对消耗率、生长率、转化效率、死亡率、体重和发育的影响。P. dissecta和M. sexmaculatus 的所有幼虫比 IGP 更喜欢吃卵，而C. septempunctata 的低龄没有表现出偏好，其较高的龄期更喜欢反之亦然。这三个物种在单型同种和异种鸡蛋饮食中成功发育。然而，当以同种卵为食时，龄期发育更快，进入较重的生命阶段，死亡率较低。三瓢虫种类的四龄有更高的消费率和转化效率，而一龄的增长率高于其他龄。当幼虫以蚜虫为食时，这些参数是最佳的，而同种鸡蛋比异种鸡蛋更好。C. septempunctata的消费率高于其他两种瓢虫物种，但在增长率和转化效率方面落后于两者。当三只瓢虫的龄期以蚜虫为食，其次是同种卵和异种卵时，总体死亡率最低。我们还得出结论，C. septempunctata蛋对于同种和异种捕食者来说可能不太可口，而后者通过避免公会内捕食而不是冒着健康风险来确保生存。