Description of the sexual generation of Disholcaspis quercusmamma (Walsh) (Hymenoptera: Cynipidae)

Previous descriptions of the rough bulletgall wasp, Disholcaspis quercusmamma (Walsh), have involved only the asexual generation which emerges from conspicuous twig galls in autumn. As with many other Cynipids, the life cycle of D. quercusmamma, alternates between asexual and sexual forms, yet the sexual generation remains undescribed. Observations in 2009 revealed minute bud galls that were exposed during leafing and were thought to be produced by this alternate generation. The purpose of this project was to define the biological and physical characteristics of the sexual generation of D. quercusmamma. Specimens were reared from galls and a subsample was used in a rearing experiment to confirm their relation to the recognized asexual generation. Seasonal activity of D. quercusmamma was monitored with yellow sticky traps and beating samples. A morphological description was constructed based on wasps reared from galls collected in Larimer County, CO from May 2009 to June 2010. The sexual generation, in Northern Colorado, was observed emerging from late May to mid-June. Knowledge of all forms of D. quercusmamma increases our understanding of its lifecycle.