Climatic correlates of temporal demographic variation in the tropical hover wasp Liostenogaster flavolineata

Abstract

Environmental factors, and particularly climate, play an important role in influencing behaviour in many insects. In social species, climate is known to have a strong influence on social traits, but how this manifests itself in tropical ecosystems is poorly understood. In Peninsular Malaysia, the climate is characterised by relatively consistent annual temperatures with wet/dry cycles, and the tropical hover-wasp Liostenogaster flavolineata Cameron is active year-round. Newly emerged females can choose to remain at the natal nest and help, or disperse and found their own nest depending on a balance of ecological and demographic factors. We collated long-term adult and brood census data for populations of L. flavolineata in Peninsular Malaysia in three different years to investigate temporal variation in demographics (brood and adult numbers) and how this might be related to climatic factors. Our data indicate that there are multiple, temporally distinct peaks of brood production in this population. The number of newly eclosing females and number of mature brood were positively associated with temperature and negatively associated with the number of rain-days during the observation period. Furthermore, larger females were produced during the peaks of brood production. We speculate how these patterns may influence the staying or leaving decisions of newly emerged females in a primitively eusocial species such as L. flavolineata.