An outbreak of Gynanisa maja (Lepidoptera: Saturniidae) larvae in the south-eastern lowveld of Zimbabwe.

Abstract

The larvae of speckled emperor moths (Gynanisa maja) are important plant defoliators in savanna ecosystems of southern Africa and a valuable food resource for indigenous communities. Population explosions of G. maja larvae can negatively impact an area's primary productivity thereby altering herbivory patterns and associated ecosystem processes. Harvests of the larvae enhance socio-economic livelihoods of local people by providing a source of protein and improving household incomes. We report on a population outbreak of G. maja larvae that occurred in south-eastern Zimbabwe between December 2022 and January 2023 and discuss the ecological and social significance of the event. A total biomass weight of 5811 tons of G. maja larvae was estimated over the area of the outbreak and extensive defoliation was recorded in Colophospermum mopane trees. We could not associate the outbreak with any obvious environmental conditions and speculate that it may have been caused by subtle triggers that are not easily identified.