VARIATION IN REPRODUCTIVE COMPATIBILITY IN TRICHOGRAMMA AND ITS TAXONOMIC SIGNIFICANCE (HYMENOPTERA, TRICHOGRAMMATIDAE)

One hundred thirty-two cross-breeding experiments among populations of Trichogramma pretiosum Riley, T. deion Pinto and Oatman, and the T. minutum Riley complex are summarized. Results show that extremely complex patterns of reproductive compatibility exist among collections considered conspecific on morphological grounds. These include complete compatibility, varying levels of partial one- and two-way incompatibility, and complete incompatibility. Reproductive relationships appear to be correlated with geographic range in the minutum complex but not in T. pretiosum or T. deion. Reproductive disjunction among laboratory cultures has frequently served as justification for formal species recognition in Trichogramma. The advisability of this practice is discussed, given the considerable intraspecific variation in compatibility.