Light and dark rhythms of pupal eclosion and egg hatching in tropical stem borers’ moths

Abstract

Different traits in insects such as locomotor activity, egg-hatching, emergence from puparia and oviposition follow light and dark rhythms. In noctuid stemborer moths, activity cycles of the adults linked to their reproductive traits concentrate at the first half of the night and some of them are highly species specific. However, little information is available on the light and dark rhythm of egg hatching in noctuid stemborer moths as compared to adult’s activities (emergence, oviposition and mating). The purpose of this study was to compare the light and dark rhythms of pupal eclosion and egg hatching, respectively, for four main species of Afro-tropical noctuid stemborers under 24 h light-dark cycle conditions. In contrast to pupal eclosion, egg-hatching showed to be less controlled by light and dark rhythms. This arrhythmic pattern on egg-hatching compared to pupal eclosion is discussed in terms of interspecific resource utilization within a community of lepidopteran stemborers sharing the same resource.