Notes on the overwinteringApanteles-Tetrastichus-Lysibiacomplex (Hymenoptera: Parasitica), parasitoids of the large white butterfly

Abstract

Apanteles glomeratus (L.) (Hymenoptera: Braconidae) is the main parasitoid responsible for limiting populations of Pieris brassicae (L.) (Lepidoptera: Pieridae), but Tetrastichus galactopus (Ratzeburg) (Hymenoptera: Eulophidae) and Lysibia nana (Gravenhorst) (Hymenoptera: Ichneumonidae), in turn, greatly limit the primary parasitoid population, reducing its potential for constraint of the future pierid population. The patterns of spring emergence of these species from overwintering A. glomeratus cocoon clusters have functional significance. The sex ratio of emerging A. glomeratus is significantly correlated with the cluster size, higher proportions of females emerging from the larger clusters. Non-ovipositional attacks by T. galactopus appear to cause heavy mortality in the Apanteles cocoon clusters. L. nana oviposits in cocoons of A. glomeratus, whatever they contain, and very active female L. nana lay higher proportions of diploid eggs than do lower status females.