Foraging Behavior of Anopheles gambiae (Diptera: Culicidae) on Parthenium hysterophorus (Compositae) and Senna occidentalis (Fabaceae)

Foraging behavior of Anopheles gambiae, a malaria vector, was analyzed on Parthenium hysterophorus and Senna occidentalis through the use of video recordings. The two plant species are invasive plants known to be exceptionally attractive to An. gambiae but thought to yield very different amounts of sugar. With the importance of sugar as an energy reserve for flying, mating, blood feeding, and reproduction, foraging and finding access to sugar is a critical component of the life of a mosquito. Due to the differences in sugar production of the two plants, I hypothesized that foraging behavior of An. gambiae would differ greatly between the two plants, with more sugar being obtained from S. occidentalis On P. hysterophorus, the putative sugar- poor plant host, mosquitoes spent significantly more time on plants with flowers than without. On plants with flowers, both males and females exhibited a directed search for sugar, landing and foraging primarily on the prominent flowers and spending well over half of their time involved in foraging behavior (probing) on all parts of the plant. Males and females spent 80% and 58% of their time, respectively, on flowers, with 99% and 77% of that time devoted to foraging. However, for all their effort, they seldom obtained a sugar meal, with only 3.1% of males and 11.3% of females testing positive for fructose. On S. occidentalis, which produces visible amounts of sugar on prominent extra-floral nectaries, males and females spent 22% and 32% of their time, respectively, on EFNs, with 86% and 88% of that time devoted to foraging. After foraging on S. occidentalis, 46.2% of males and 50% of females were positive for fructose. S. occidentalis was more beneficial to An. gambiae in terms of energetics, and should be the focus of further malaria-control research.NIH grant R01-AI077722 from the National Institute of Allergy & Infectious Medicine to W.A.F.No embargoAcademic Major: Evolution and Ecolog