Behavioural interactions between the solitary koinobiont parasitoid, Venturia canescens, and two of its hosts, Plodia interpunctella and Corcyra cephalonica, were investigated. The response of both hosts to simulated antennation using a two-haired brush was examined over instars 3 (L3) to 5 (L5). Young P. interpunctella larvae predominantly adopted escape tactics (writhe, trash) whereas L5 P. interpunctella usually froze after the stimulus was applied. L3 C. cephalonica larvae were more aggressive (headrear, flick) than P. interpunctella in response to the application of the stimulus, but older C. cephalonica responded less aggressively than in earlier instars. Although V. canescens readily jabbed its ovipositor at both hosts after antennation, P. interpunctella was considerably more susceptible to parasitoid attack than C. cephalonica, irrespective of size in the final (L5) instar. C. cephalonica, the larger, more aggressive host, actively resisted parasitism whereas P. interpunctella responded much more passively after parasitoid contact. Parasitoids examined and jabbed their ovipositors at dead hosts, but this behaviour was not sustained, implying that host movement stimulates parasitoid attack. On patches containing V. canescens, L5 C. cephalonica and P. interpunctella, most P. interpunctella larvae responded by freezing after parasitoid contact. P. interpunctella that froze usually avoided parasitism, whereas larvae that attempted to escape by crawling were pursued with vigour by V. canescens and usually parasitized. Irrespective of behaviour after parasitoid contact, C. cephalonica displayed more aggressive behaviour and had much greater success iri warding off parasitoid attack. Host acceptance by V. canescens is clearly affected by the size and species of the host it attacks. The influence of host defensive behaviour is discussed in relation to the evolution of parasitoid counter-defences and oviposition strategies.
- Plodia interpunctella
- Venturia canescens
- Corcyra cephalonica
- defensive behaviour
Harvey, J. A., & Thompson, D. J. (1995). Host behaviour and its influence on foraging and acceptance by the solitary parasitoid wasp, Venturia canescens (Hym: Ichneumonidae). Entomophaga, 40(2), 193-210. https://doi.org/10.1007/BF02373068