Effect of honeybee products, as food supplements, on the biological activities of three Trichogramma species (Hymenoptera: Trichogrammatidae)

Egg parasitoids play a significant role in biological control for lepidopteran insects, where they kill the eggs (the first stage of the developmental cycle). Trichogramma species are the very important ones of these egg parasitoids. Under natural conditions, adult Trichogramma species are known to feed upon nectar, pollen, and honeydew. Here, the effects of four honey bee products; honey, pollen grains, royal jelly, propolis, their mixtures, and sugar solution, as food supplements, on longevity, fecundity, emergence rate, and sex ratio on different Trichogramma species were evaluated. Three species, Trichogramma evanescens, T. bourarachae, and T. cacoeciae, differed in their responses to the tested diets. In general, all diets containing honey improved longevity and fecundity. Honey + royal jelly and honey + propolis were the most diets improved the longevity of T. evanescens. Honey + royal jelly + propolis and honey alone resulted in the longest lifetime for T. bourarachae. While the best diets that prolonged the longevity of T. cacoeciae were honey + royal jelly and honey alone. The highest fecundity was obtained by honey + royal jelly + propolis, honey + royal jelly, honey alone and honey + pollen grains + royal jelly for T. evanescens, honey + royal jelly + propolis, honey + pollen grains + propolis, and honey + pollen grains + royal jelly + propolis for T. bourarachae, and by honey + royal jelly, and honey alone in case of T. cacoeciae. The emergence rate had not affected by most of the treatments for three Trichogramma species. Food supplements caused an indirect effect on sex ratio of T. evanescens and T. bourarachae, whereas long-lived females were male-biased progeny. Except when T. evanescens females were fed on honey + royal jelly and T. bourarachae on honey + royal jelly, and honey + pollen grains + royal jelly, they lived for a long time but that did not decrease the female progeny percentage. Thus, providing a suitable diet may help to enhance the biological activities for the rearing parasitoids.