Bulletin of Entomological Research

Table of Contents - 2006 - Volume 96, Issue 03  

Review Article

The effect of temperature and humidity on the bionomics of six African egg parasitoids (Hymenoptera: Trichogrammatidae)

A. Kalyebia1 c1, W.A. Overholta2, F. Schulthessa1, J.M. Muekea3 and S. Sithananthama1

a1 International Centre of Insect Physiology and Ecology, PO Box 30772-00100, Nairobi, Kenya

a2 Indian River Research and Education Center, University of Florida, 2199 South Rock Road, Fort Pierce, Florida 34945, USA

a3 Department of Zoology, Kenyatta University, PO Box 43844, Nairobi, Kenya

Abstract

The life table statistics of six native Kenyan species/strains of Trichogramma and Trichogrammatoidea were established using a factitious host Corcyra cephalonica, Stainton (Lepidoptera: Pyralidae), at eight different temperatures (10, 15, 20, 25, 28, 30, 32 and 35°C) and two humidity levels (40–50 and 70–80%). The objective was to select insects with superior attributes for augmentative release against lepidopteran pests in horticultural crops. Both temperature and humidity affected developmental time and life table parameters of the parasitoids but temperature played a more critical role. Developmental time was inversely related to temperature. The intrinsic and finite rates of increase increased with temperature up to 30°C. Both net reproduction rate and intrinsic rate of increase were higher at the lower humidity. Temperature inversely affected generation time of parasitoid strains regardless of the relative humidity. Two strains of Trichogramma sp. nr. mwanzai collected from both low and medium altitudes and Trichogrammatoidea sp. nr. lutea from the mid-altitudes, were better adapted to both low and high temperatures than the other strains, as indicated by the high intrinsic and net reproductive rates, at both humidity levels. These three strains appear to be promising candidates for augmentation biocontrol against the African bollworm Helicoverpa armigera in Kenya.

(Accepted February 04 2006)

Keywords

Correspondence:

c1 *Fax: 256 41 531061 E-mail: akalyebi@yahoo.com