Extrafloral Nectar, Honeydew, and Sucrose Effects on Searching Behavior and Efficiency of Microplitis croceipes (Hymenoptera: Braconidae) in Cotton

Abstract

The influence of extrafloral nectar, sucrose, or whitefly honeydew on host- and food-searching behavior of Microplitis croceipes (Cresson) females was investigated. Retention time, parasitization rate, time allocation to host damaged leaves and time interval between subsequent host attacks were compared in different cotton, Gossypium hirsutum L., patch treatments containing Heliocoverpa zea (Boddie) hosts. Parasitoids that were starved for 2 d before release to patches with either sucrose or extrafloral nectar showed longer retention times and higher rates of parasitization than those not able to feed. The presence of food in the patch increased the time allocated to damaged leaves, but did not reduce the time interval between host attacks. Parasitoids that fed in patches with honeydew showed a similar performance to parasitoids in patches without any food, probably as a result of the relatively low quantity and quality of this food source for M. croceipes. The initial and subsequent detect-ability of different food sources was also investigated. More parasitoids found extrafloral nectar than sucrose in a first release. However, in a subsequent release, nectar and sucrose were found equally fast. Therefore, parasitoids showed an innate attraction to extrafloral nectar, whereas learning may have influenced orientation to sucrose. The importance and use of cotton extrafloral nectar as food source for adult parasitoids and the means of using extrafloral nectar as part of a pest management strategy in biological control are discussed.