Meeting Abstract
Hematophagous mite infestations induce European starling (Sturnus vulgaris) nestlings to shift resource investment between immune function and growth. Additional research, designed to determine which aspects of mite infestation influence these trade-offs, has been hindered by variability in mite control methods. The literature describes several methods that vary in their efficacy for reducing ectoparasites in nests, as well as in their ectoparasite-independent effects on nestling development. This experiment assessed both the efficacy of several ectoparasite control methods for hematophagous mite reduction in starling nests, and their developmental effects on nestlings. After clutch completion, nests were inoculated with ≈ 100 Northern fowl mites to simulate an infestation. To assess mite load prior to mite control treatment, blood spots on the eggs of each nest were assessed 10 days after clutch completion. On brood day 0, nests were placed into one of four mite control treatments: control, heat, yarrow oil, and permethrin. These nest treatments were applied on brood day 0 and again on brood day 10. Nestling growth was assessed on brood days 5, 10, and 15. Blood was collected on brood day 15 to analyze hematocrit, hemoglobin and blood glucose concentrations. Preliminary analyses show no differences in growth across treatments. Nestlings in permethrin-treated nests displayed lower blood glucose concentrations, and higher hematocrit levels than nestlings in the control treatment. Nestlings in heat-treated nests had higher incidences of hematophagous mites and flies on their body compared to the other treatment groups. Results will be discussed further in light of ongoing analysis of bacterial killing capacity of plasma and assessment of post-fledging mite load in nests.
