Effects of prey resource fluctuation on predation attributes of two sympatric Coccinellidae (Coleoptera)

Abstract

AbstractUnder natural conditions, prey resources may fluctuate considerably in space and time; and predators are continuously faced with challenges of resource availability and use. In this study, effects of fluctuations (scarce/optimal/abundant) in biomass of pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) during rearing and experimental conditions on certain predatory attributes (consumption rate/conversion, efficiency/growth rate) of two sympatric aphidophagous Coccinellidae (Coleoptera) were evaluated. Results revealed significant influence of rearing conditions on conversion efficiency and growth rate; and experimental conditions on all three predation attributes of Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae). Larvae/adults of M. sexmaculatus had similar consumption rates per rearing condition, but exhibited highest and lowest consumption rates when abruptly shifted to abundant and scarce prey experimental conditions. Further, scarce prey reared larvae/adults of M. sexmaculatus displayed highest conversion efficiency and growth rate on optimal/abundant prey experimental condition(s). However, all three predation attributes of larvae/adults of Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae) were influenced substantially by both the rearing and experimental conditions; and scarce prey reared larvae/adults exhibited highest predation attributes on optimal/abundant prey experimental condition(s). Moreover, predation attributes of M. sexmaculatus were higher than P. dissecta on the three experimental conditions. Therefore, this study suggests that M. sexmaculatus has a better compensatory ability to overcome prey resource fluctuation than P. dissecta.