Omnivore diet composition alters parasite resistance and host condition

Diet composition modulates animals' ability to resist parasites and recover from stress. Broader diet breadths enable omnivores to mount dynamic responses to parasite attack, but little is known about how plant/prey mixing might influence responses to infection.Using omnivorous deer mice (Peromyscus maniculatus) as a model, we examine how varying plant and prey concentrations in blended diets influence resistance and body condition following infestation by Rocky Mountain wood ticks (Dermacentor andersoni).In two repeated experiments, deer mice fed for 4 weeks on controlled diets that varied in proportions of seeds and insects were then challenged with 50 tick larvae in two sequential infestations.The numbers of ticks successfully feeding on mice declined by 25% and 66% after the first infestation (in the first and second experiments, respectively), reflecting a pattern of acquired resistance, and resistance was strongest when plant/prey ratios were more equally balanced in mouse diets, relative to seed-dominated diets.Diet also dramatically impacted the capacity of mice to cope with tick infestations. Mice fed insect-rich diets lost 15% of their body weight when parasitized by ticks, while mice fed seed-rich diets lost no weight at all.While mounting/maintaining an immune response may be energetically demanding, mice may compensate for parasitism with fat and carbohydrate-rich diets.Altogether, these results suggest that a diverse nutritional landscape may be key in enabling omnivores' resistance and resilience to infection and immune stressors in their environments. Broader diet breadths enable omnivores to mount dynamic responses feeding to parasite attack, but little is known about how plant/prey mixing might influence responses to infection. These results suggest that a diverse nutritional landscape may be key in enabling omnivores' resistance and resilience to immune stressors in their environments.image

Automated summary

Diet composition has an impact on animals' ability to resist parasites and recover from stress. This study focused on how plant/prey mixing in diets influenced resistance and body condition in omnivorous deer mice infested with Rocky Mountain wood ticks. The findings suggest that a diverse nutritional landscape is crucial for omnivores to withstand infection and immune stressors in their environments.