Poligamia e o desempenho reprodutivo de Tenuisvalvae notata (Mulsant) (Coleoptera: Coccinellidae)

Abstract

Biological control using predatory insects has been an alternative for pest control. Amongst insect predators, the ladybird beetle Tenuisvalvae notata (Mulsant) stands out by being specialist in Pseudococcidae. This ladybird beetle is polygamous and multiple matings may imply some costs and benefits for its reproductive performance and survival. In this study, we investigated the effects of polygamy on the reproductive performance of T. notata, through partner choice, adult female reproductive success, adult survival, male virility, offspring development, and the morphology of the spermatheca. Results show that there was a preference of couples in copulating with known partners. Younger females had higher fecundity and longer longevity when mated only once in comparison to older females and/or those mated multiple times. There were no effects on fecundity, fertility and offspring development between the treatments. In contrast, fecundity and fertility decreased along the oviposition period for all evaluated treatments. The morphology of the spermateca of virgin and mated females is similar, as well as amount of carbohydrates and proteins. The spermatheca is simple, rhiniform, well sclerotized and consists only of the receptacle and spermatic duct. There were no spermatozoids stored in the spermatheca of females mated only once, but spermatozoids were found in the spermatheca of females mated multiple times. Therefore, we suggest that even though T. notata is polygamous and has a spermatheca to store of seminal material, it can be monogamous if given the chance, and polygamy is maintained to replace the spermatozoa over time and to guarantee offspring genetic variability.