Reprodução e desempenho da descendência em Eriopis connexa (Germar) (Coleoptera: Coccinellidae)

Abstract

The lady beetle Eriopis connexa (Germar) is widely distributed in the agroecosystems, and the occurrence of populations naturally selected for resistance to pyrethroids make this species an interesting agent of biological control to be preserved in pest control programs. Due to its importance, this study aimed to define the age of sexual maturity, the selection of sexual partners, and the paternity of descendants. In addition, the oviposition of infertile eggs was investigated as a function of the insecticide-resistant phenotype and food scarcity; and if the fitness of this species is affected by cannibalism, and intraguild predation upon eggs of Coleomegilla maculata DeGeer. Results show that the sexual maturity in E. connexa started within 3 days of adult emergence, but fully developed after 5 days. The highest frequency of mating occurred within first hour of pairing within photophase, and the phenotype for insecticide resistance did not affect the choice of a mating pair. The progeny paternity results from a mixture of available sperm, and do not depend on mating order. The oviposition of infertile eggs was similar between the susceptible and resistant phenotypes regardless of clutch size. Also, prey scarcity affected fecundity, but not infertile egg laying. Females fed only conspecific eggs did not improve fitness. On the other hand, egg cannibalism and intraguild predation mixed with standard prey increased larval and adult fitness. Cannibalism and intraguild predation were common but less frequent under the high density of the extraguild prey (e.g. aphids), prevailing the aphidophagous behavior in E. connexa. These results suggest that the resistant and susceptible E. connexa populations have a simple perspective on progeny production and that egg cannibalism and intraguild predation have an important role as a diet supplement. However, there was not a complete understanding of the frequent oviposition of infertile eggs, even under supposedly optimal mating conditions.