Influence of intraspecific competition for food on the bodyweight of the adult aphidophagous ladybird, Coccinella transversalis

Abstract

Aggregation of conspecific predators sharing a common prey, influences their bodyweights. We investigated the influence of intraspecific competition of adult ladybirds of Coccinella transversalis Fabricius on their bodyweight feeding on rusty plum aphid, Hysteroneura setariae (Thomas). Adult males and females consumed a significantly greater number of aphids with increase in predator-density, however, the aphid-consumption per predator declined with this increase. The weight gain per predator also decreased linearly with increase in the density of both male and female predators. This indicates that the weight-gain of the predator is a function of the prey consumed. The searching efficiency decreased with increase in predator density due to mutual inference. The mutual interference constants for adult male and female ladybirds were −0.419 and −0.546, respectively. The females consumed a greater number of aphids than males. The killing power of the ladybird denoted by the k-value increased curvilinearly with increase in predator density. We conclude that prey consumption is a function of body size and that the offspring of those that aggregate at low densities in prey-rich habitats develop into large adults.

Diet and body size modulate the remating behaviour of a predaceous ladybird, Coccinella transversalis (Fabricius) (Coleoptera, Coccinellidae)

“…Coccinella transversalis (Fabricius) is an aphidophagous ladybird (Coleoptera, Coccinellidae) of the Oriental region with a wide prey range (Omkar and James, 2004) and biocontrol prospects (Michaud et al, 2013). It suppresses the population of aphid, Hysteroneura setariae (Thomas) (Pervez and Sharma, 2021), and can survive on non-aphid foods during aphid scarcity (Maurice et al, 2011). During aphid scarcity, females have pressure to optimally forage (Kindlmann and Dixon, 1993) and males to search for potential mates (Dixon, 2000), which probably depends on bodysize.…”

Invasive freshwater snails are less sensitive to population density than native conspecifics

“…Interactions between conspecifics can profoundly influence morphology (e.g., Bhavanam & Trewick, 2022), reproduction (e.g., Kobayashi, 2019), competition for mates (e.g., Ode et al, 2022), and other key aspects of population dynamics of potentially invasive species (e.g., Karatayev et al, 2015). In particular, population density might reasonably affect intraspecific competition, which can in turn influence dispersal (e.g., Grabowska et al, 2019), behavior (e.g., Adey & Larson, 2021), and life-history traits (e.g., McCann et al, 2019;Pervez & Sharma, 2021;Ward et al, 2013). Here, we evaluate whether key life-history traits (growth rate, embryo production, embryo presence vs. absence) are differentially affected by conspecific population density in invasive versus native P. antipodarum by manipulating the population density experienced by juvenile representatives of multiple native and invasive snail lineages and quantifying their individual growth rate and embryo production.…”

Prey preference of an aphidophagous ladybird, Coccinella transversalis (Coccinellidae: Coleoptera) on two aphid species

“…~ 262 ~ Coccinella transversalis (Fabricius) is an aphidophagous ladybird of the Oriental region with a wide prey-range and can be found preying upon the colonies of aphids infested on local agricultural and horticultural crop plants. Quality food is directly associated with an increase in its body weight (Pervez and Sharma, 2021) [16] . Since plant allelochemicals have a major role in the preference and suitability of prey, we hypothesize that A. craccivora reared on the toxic R. sceleratus will be less preferred when mixed with different proportions of A. gossypii.…”