This study characterized bot fly (Cuterebra fontinella) parasitism in a local population of white-footed mice (Peromyscus leucopus) in Cincinnati, Ohio. The researchers found that the prevalence and intensity of parasitism varied significantly between study sites, with one site having the highest levels. Infected mice were found to be in better physical condition than uninfected mice. While no effects of parasitism were seen for sex, age, or reproductive activity, spatial factors like habitat characteristics and landscape features likely influence patterns of bot fly infection in this host population.

1. Population-level Effects of Bot Fly ( Cuterebra fontinella ) Parasitism on White-footed Mice ( Peromyscus leucopus ) Michael J. Cramer and Guy N. Cameron Department of Biological Sciences University of Cincinnati Cincinnati, OH 45221-0006

2. Why Study Parasitism? Common interspecific interaction Potential affect on population ecology of both host and parasite species Coevolutionary dynamics Often overlooked despite great potential impact on host biology

3. Bot Fly Parasitism Common parasite-host system Studied for decades Occurs in many host taxa worldwide Rodentia: mice and rats Lagomorpha: rabbits Perissodactyla: horses Artiodactyla: cattle

4. Rodent Bot Fly Life Cycle Females lay eggs in host habitat. Hosts pick up newly hatched larvae . Larvae migrate to inguinal region and develop warble. After 3 rd instar, larvae exit host and burrow underground to pupate. Flies emerge and mate at aggregation sites. 5 days 21 days P. Meyer C. N. Shiffer M. J. Cramer

5. Objectives Characterize bot fly parasitism in local host population of Peromyscus leucopus Determine population patterns in infection Assess potential cost to host population of bot fly parasitism

6. Study Sites Site4 Site3 Site1 Site2 Cincinnati (39 km)

7. Population Parasitism

8. Population Parasitism

9. Sex X 2 = 0.042 p > 0.05 t = 0.367 p > 0.05

10. Reproductive Activity X 2 = 0.054 p > 0.05 t = -1.434 p > 0.05

11. Age Class X 2 = 2.360 p > 0.05 t = -0.700 p > 0.05

12. Condition t = 3.287 p = 0.001 r = -0.410 p > 0.05

13. Site X 2 = 18.300 p < 0.001 F = 11.772 p < 0.001

14. Conclusions Spatial aspect of parasitism Infected animals in better condition than uninfected animals Potential effect on reproduction

15. Spatial Aspect of Parasitism Site 4 had highest prevalence and intensity of parasitism No evidence that host population is different Habitat characteristics Landscape effects: aggregation sites Vegetation structure: egg laying sites Soil characteristics: pupation sites

16. Condition Infected animals in better condition than uninfected animals Lab study shows that infected animals increase food intake (Hunter and Webster 1974) Food not limiting for Peromyscus in summer Increase in weight would affect condition index

17. Reproduction Peaks in seasonal reproductive activity occur when parasitism low Trend in data suggests that inactive animals have more bot flies Potential for behavioral effects of bot flies on reproduction

18. Further Study Habitat characterization of each site Determine if habitat characters are correlated with prevalence and intensity of bot fly infections Landscape analysis Behavioral studies Aggression studies Mate choice

19. Acknowledgements Research Advisory Committee George Uetz Ken Petren Michal Polak Thomas Kane Nancy Solomon Permission (ODNR) Todd Haines Randy Morgan Field Assistance Diane McCubbin Kelly Roberts Ashley Mattingly Theresa Pfarr Cory Christopher Alicia Shelton Funding Wieman Summer Research Award