Uscana lariophaga, West‐African egg parasitoid of the cowpea bruchid beetle Callosobruchus maculatus: photoperiod, parasitization and eclosion interactions

Abstract

AbstractThe diurnal pattern of parasitization and eclosion of the trichogrammatid Uscana lariophaga Steffan, egg parasitoid of the cowpea bruchid Callosobruchus maculatus (Fabricius) was studied for L12:D12 photoperiods. The wasp parasitized eggs throughout each 24‐h period with about 70% of the parasitization taking place during the first 12 h regardless whether it was the photophase or the scotophase. More female progeny was produced when the first 12‐h period was photophase instead of scotophase. Eclosion of wasps took place over a period of 4 days and occurred during the second half of the scotophase and the first half of the photophase. The number of wasps eclosed during the photophase was similar to that eclosed during the scotophase. Average development time was 8.9 days at 30°C. Male development was completed 6 to 8 h before the females, hence a higher percentage of females emerged in the later eclosion peaks. During scotophases more females eclosed than during photophases. Although the results indicate that the wasp is able to perform under dark storage conditions the effect of permanent low light intensity remains to be studied.