Assaying Male-Male Interactions Within Nasonia (Hymneoptera: Pteromalidae)

Abstract

Competition is an important ecological process that shapes ecosystems and in- fluences species diversity and coexistence. Interference competition among or- ganisms can result in aggression within and across different species. Within the genus Nasonia, intraspecific aggression is well studied, whereas interspecific aggres- sion has lagged. This study investigates male-male conspecific and hetero-specific interactions within the four Nasonia wasps, focusing on aggression, dominance- submissive, and species-specific behavioural differences. Conspecific and heterospe- cific males were paired, videotaped, and analysed to obtain an ethogram. The behaviours were further characterised, and frequencies were plotted. Even though the males show similar behaviours, the extent varies within and across species. N. vitripennis males exhibit strong territoriality and aggression, dominating over other species in interspecific pairs, followed by N. longicornis. Meanwhile, N. oneida and N. giraulti display comparable levels of aggression. A dominance hi- erarchy was calculated based on aggressive and submissive scores for each species pair, which follows the order: N. vitripennis > N. longicornis > N. giraulti ∼ N. oneida. Our results provide input into the competitive dynamics within the Na- sonia genus, and further comparative analyses can be undertaken to understand the degrees of aggression and the impact of female presence on male interactions.