HOST FEEDING, EGG MATURATION, RESORPTION, AND LONGEVITY IN THE PARASITOID APHYTIS-MELINUS (HYMENOPTERA, APHELINIDAE)

I investigated several physiological factors associated with host feeding in the parasitoid, Aphytis melinus DeBach. Host feeding refers to the consumption of host tissues or fluids by the adult female wasp. Dynamic behavioral models developed for the decision of whether to host feed or oviposit in Aphytis highlighted the importance of parasitoid egg load (number of mature eggs) and two physiological features: whether host feeding supplies nutrients to a metabolic requirement as well as to egg maturation and the presence and length of an egg maturation delay; i.e., the time required to convert a host-feeding meal to mature eggs. I therefore investigated these two features in Aphytis. Host feeding appeared to supply a metabolic nutrient demand as well as egg maturation in Aphytis; females that received honey ad libitum but no host meals resorbed eggs until they had few or no eggs left and then died. By contrast, female Aphytis given a host meal and honey ad libitum produced more eggs-with an almost-equal-to 12- to 18-h egg maturation delay-and ultimately lived longer. Other parasitoids may have physiologies similar to Aphytis but too few data exist to make conclusions about broad patterns of the function of host feeding in parasitoids.