Changes in Biological Characteristics of Trichogramma pretiosum (Hym.: Trichogrammatidae) Reared on Eggs of Anagasta kuehniella (Lep.: Pyralidae) for 23 Generations

Abstract

Possible changes in biological characteristics of Trichogramma pretiosum (Riley) (Hymenoptera: Trichogrammatidae) were monitored during 23 generations reared on eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae), to determine quality control parameters in rearing procedures of this parasitoid. Parasitism rates (percent of eggs parasitized) of T. pretiosum varied from 10 to 76%, with lower values for the first four generations. From the 17th generation, the variability in the parasitism rate was lower. Viability (percent adult emergence rate) of T. pretiosum in eggs of A. kuehniella varied from 22 to 100%, again with lower values in earlier generations. Adult longevity of T. pretiosum varied from 5.3 to 15.9 days, and showed a reduced longevity with increasing number of generations. Sex ratio of the offspring of this parasitoid was not affected by the timing of parasitism on eggs of A. kuehniella.

Keywords:

• Biological control
• Trichogrammatidae
• quality control
• alternative host

Acknowledgments

To the ‘Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)’, to the ‘Coordena {\rm\cedil{c} } ão de Aperfei {\rm\cedil{c} } oamento de Pessoal de Nível Superior (CAPES)’ and to the ‘Funda {\rm\cedil{c} } ão de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)’. To Dr Andrew Lock from CSIRO, Australia, and Dr Charles Eyre, England, for reviewing the manuscript.