THE SWARMING BEHAVIOUR OF EPISYRPHUS BALTEATUS (DE GEER) (DIPTERA: SYRPHIDAE)

摘要

Initial observations of the swarming behaviour of the male hoverfly Episyrphus balteatus (De Geer) were undertaken in a wood in west Northamptonshire (VC32), during July/August 2007. Basic equipment (a voice recorder) was used and several interestingaspects of the swarming behaviour of male E. balteatus were revealed. Clusters of sunlit leaves, located on the northern edge of the swarm site (lek) were found to be used as swarm markers. A maximum swarm population size of 20 is suggested and lek fidelity is posited. Frequency distributions of hovering, basking and chasing activities were constructed, revealing that the average swarming male E. balteatus spent nearly twice as much time hovering as it does basking and that both activities were interspersed with short conspecific and heterospecific chases. Several differences between the conspecific and heterospecific chases were noted, including a possible spiralling courtship flight pattern.