Stage and age-specific predation in four aphidophagous ladybird beetles

Abstract

Abstract In the present study, stage- and age-specific predatory patterns and nutritional ecology attributes of four co-occurring aphidophagous ladybirds, namely, Coccinella septempunctata (L.), Coccinella transversalis F., Cheilomenes sexmaculata (F.) and Propylea dissecta (Mulsant) on pea aphid, Acyrthosiphon pisum (Harris) were investigated. Despite their lower consumption rates, smaller ladybirds (C. sexmaculata and P. dissecta) and earlier instars were efficient converters of aphid prey with higher relative growth rates, over the respective larger ladybirds (C. septempunctata and C. transversalis) and fourth instars. The consumption rates of pea aphids by the larvae increased with stage, but with a decline in the later part of the fourth instars, just prior to pupation. Adult females of early age groups (between 2 and 7 days) had higher consumption rates than later age groups in all the four species. Further in adult females, consumption rates decrease with increase in age, but without significant changes in conversion efficiencies and relative growth rates. Keywords: conversion efficiencyconsumption raterelative growth rate Coccinella septempunctata Coccinella transversalis Cheilomenes sexmaculata Propylea dissecta Acknowledgements The authors are thankful to the Government of Uttar Pradesh, India for providing funds in the form of Centre of Excellence in Biocontrol of Insect Pests and also to Head, Department of Zoology, University of Lucknow for laboratory facilities and encouragement.