THE THELYTOCOUS TRICHOGRAMMA-CHILONIS IN TAIWAN

Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) with a mode of reproduction different from arrhenotoky was discovered and maintained in the laboratory. With or without mating, individuals of this form were able to produce males, females, and mosaics which varied in morphological characters. Reciprocal and backcrosses between males and females from this form and the arrhenotokous population revealed that they were compatible in mating. Progeny obtained from F1 and F2 proved the existence of gene flow between these two forms which are morphologically indistinguishable. More males were produced as temperature rose to above 25-degrees-C, or when females fed on a mixture of tetracycline-hydrochloride and honey (1 mg/1 ml). The impact of parasitoids with such mode of reproduction on biological control is discussed.