PhD Candidate Texas A&M University College Station, Texas
Dipteran flies are ubiquitous in boreal habitats where moose (Alces alces) feed and rest. The majority of flies on a moose are moose fly (Haematobosca alcis), a species that completes its entire life cycle on or around moose. Flies impose physiological costs on moose. The most evident costs of flies for moose are the hind leg sores caused by legworm (Onchocerca sp.), transmitted by flies. We found that the number of sores present on the hind legs of moose is positively correlated with the fat stores of a moose, which suggests that foraging gains of energy increase with exposure to flies. We also found that the number of sores is negatively correlated with serum albumin, which is consistent with the use of body protein to repair injuries from flies and parasites. The number or type of flies present on a moose were not correlated with the concentration of corticosteroids in saliva or feces. Flies do not elicit a stress response in moose even though the costs of repairing wounds and resisting infections of those wounds probably reduce gains of protein from foraging in summer. Tolerance of flies in summer risks longer term costs of endoparasites that continue to injure the animal through winter.
