关键词: 七星瓢虫, 狭臂瓢虫, 瓢虫, 温度, 光周期, 蚜虫

Abstract: 【Aim】 In agriculture, climatic changes affect crop yield, dynamics of aphid pests and their regulation by ladybird predators. While some ladybirds are ubiquitous and others have limited geographical ranges; but how climatic cues influence distribution of ladybirds is poorly explored.【Methods】Present study, therefore, assesses the effects of different temperatures (15℃, 20℃, 25℃, 30℃ and 35℃), and photoperiods (8L:16D, 12L:12D and 16L:8D) on consumption and utilization of the pea aphid, Acyrthosiphon pisum (Harris) by larvae of a ubiquitous ladybird ［Coccinella septempunctata(Linnaeus)］ and an Oriental/south-Asian ladybird (Coccinella transversalis Fabricius). 【Results】Although predation attributes and developmental rates of both ladybirds were the highest at 25℃ and attributes further increased with increase in day length (from 8L:16D to 16L:8D photoperiod), larvae of C. septempunctata had higher consumption, growth and developmental rates, and their newly emerged adults were heavier than those of C. transversalis at all temperatures and photoperiods. Non-linear regression model extrapolated~11℃ and~10.5℃ as lower development thresholds and ~41℃ and ~43℃ as upper development thresholds for C. transversalis and C. septempunctata, respectively. Dependency of larval predation and developmental rates to climatic cues were higher in C. transversalis than C. septempunctata. 【Conclusion】Present study, therefore, reveals that a ubiquitous ladybird is less susceptible to climatic cues than an indigenous ladybird and hence is widely distributed to different geographical regions. Thus, the former may behave as a better biocontrol agent than the latter.

Key words: Coccinella septempunctata, Coccinella transversalis, ladybirds, temperature, photoperiod, aphid