Courtship behaviour and mating refusals in an aphidophagous ladybird, Coccinella transversalis

Abstract

We investigated the significance of sexual maturity, courtship behaviour and mating refusals in an aphidophagous ladybird, Coccinella transversalis Fabricius using four mating combinations, viz. virgin couple, previously mated couple, virgin male x mated female, and mated male x virgin female. Adult females and males attained sexual maturity at a very early age of 3.47 ± 0.32 and 4.02 ± 0.75 days after emergence respectively revealing slight protogyny. Early sexual maturity trait enables early initiation of sexual activities leading to increase in its population dynamics. The male courtship displays were prominent in virgins than in the non-virgins, which indicate that males perhaps resort to courtship when they are mating for the first time. The duration of copula (24.70 ± 4.50 min) and the number of bouts (343.60 ± 56.53) were greater in the copulation of non-virgins than that of the virgins (17.19 ± 5.19 min of copulation with 265.90 ± 79.73 bouts). The female mating refusals were higher in mated females than in virgins suggesting that females resist to re-mate due to probable sufficiency of single mating for their progeny. Both early sexual maturity and increased incidences of mating refusals by the mated females seemingly are traits that favour sexual selection. Attainment of early sexual maturity and offspring production might help mass-rearing of C. transversalis for the aphid biocontrol programme.