Venturia canescens (Gravenhorst)
(Formerly known as Nemeritis canescens Gravenhorst)
Taxonomic placing: Insecta, Holometabola, Hymenoptera, Apocrita, Ichneumonidae.
Geographical distribution: Cosmopolitan.
Morphology: The head and thorax of the adult are black, and the abdomen is red, with a long ovipositor. Antennae very long and the forewings have a rich venation. The legs are mostly dark-yellow.
Life cycle: Venturia canescens is a koinobiont endoparasitoid of the larvae of over 30 species of Lepidoptera, most in the family Pyralidae. It is very common in stored-product stores, but also occurs in the field, feeding on nectar or honeydew, finding its hosts in dried fruits like figs and dates. Its various populations reproduce by thelytoky or by arrhenotoky, producing up to 250 eggs/female at 20-25°C. It is most fecund, and lives for several (3-4) weeks, when attacking 3th-5th instar hosts (such as larvae of Ephestia kuehniella), in continuous darkness. It is attracted to the webbing of its hosts. The calculated threshold of development is at 13.2°C, and 310 day degrees are required for development.
Economic importance: Venturia canescens is an important natural enemy of several stored products pests, such as Ephestia cautella, E. kuehniella and Plodia interpunctella. When E. cautella is co-attacked by Habrobracon hebetor and by V. canescens, the latter is usually suppressed by the former. When parasitizing larvae of a strain of E. kuehniella that is tolerant to Bacillus thuringiensis (Bt), the emerging parasites were larger than those from the Bt-susceptible hosts.
References
Eliopoulos, P. A., and G. J. Stathas. 2005. Effects of temperature, host instar and adult feeding on progeny production by the endoparasitoid Venturia canescens (Gravenhorst) (Hymenoptera: Ichneumonidae). Environmental Entomology 34: 14-21.
Ha, D.-M. (and 6 co-authors). 2006. Behavioral attraction of two parasitoids, Venturia canescens and Bracon hebetor, to silk extracts of a host Plodia interpunctella. Journal of Asia-Pacific Entomology 9: 287-292.
Harvey, J.A., Thompson, D.J. and Heyes, T.I. 1996. Reciprocal influences and costs of parasitism on the development Of Corcyra cephalonica and its endoparasitoid Venturia canescens. Entomologia Experimentalis et Applicata 81: 31-45.
Özkan, C. 2007. Effect of food, light and host instar on the egg load of the synovigenic endoparasitoid Venturia canescens (Hymenoptera: Ichneumonidae). Journal of Pest Science 80: 79–83.
Podoler, H. 1974. Analysis of life tables for a host and parasite (Plodia-nemeritis) ecosystem. Journal of Animal Ecology 43: 653-670. ·
Press, J.W., Flaherty, B.R. and Arbogast, R.T. 1977. Interactions among Nemeritis canescens (Hymenoptera: Ichneumonidae), Bracon hebetor (Hymenoptera: Braconidae), and Ephestia cautella (Lepidoptera: Pyralidae). Journal of the Kansas Entomological Society 50: 259-262.
Rahman, M.M., Roberts, H.L.S. and Schmidt, O. 2004. The development of the endoparasitoid Venturia canescens in Bt-tolerant, immune induced larvae of the flour moth Ephestia kuehniella. Journal of Invertebrate Pathology 87: 129-131.
Spanoudis, C.G. and Andreadis, S.S. 2012. Temperature-dependent survival, development, and adult longevity of the koinobiont endoparasitoid Venturia canescens (Hymenoptera: Ichneumonidae) parasitizing Plodia interpunctella (Lepidoptera: Pyralidae). Journal of Pest Science 85: 75-80.