Species' life-history traits explain interspecific variation in reservoir competence: a possible mechanism underlying the dilution effect.
Authors: Huang Zheng Y X, de Boer Willem F, van Langevelde Frank, Olson Valerie, Blackburn Tim M, Prins Herbert H T
Journal: PloS one
Summary
# Editorial Summary Understanding why some animal species are better at harbouring and spreading pathogens than others could fundamentally change how we manage disease risk in multi-host systems—and this 2013 analysis suggests life-history strategy plays a crucial role. Researchers used phylogenetic comparative methods to examine relationships between species' biological traits (body mass, reproductive output, longevity) and reservoir competence across three vector-borne disease systems affecting equines: Lyme disease, West Nile Encephalitis, and Eastern Equine Encephalitis. They found that larger-bodied species showed lower competence for Lyme disease and WNE, whilst species with smaller clutch sizes (typically longer-lived animals with slower reproduction) were less competent reservoirs for EEE—suggesting that slow, conservative life-history strategies correlate with reduced pathogen transmission potential. The implications are significant: as biodiversity declines and extinction pressure removes slower-reproducing, larger-bodied species from communities, the remaining fauna becomes increasingly dominated by fast-reproducing, smaller species that are highly efficient disease reservoirs, potentially intensifying transmission risk—a mechanism that may underpin the "dilution effect" where ecological simplification paradoxically increases pathogen prevalence. For equine professionals, this reinforces that landscape-level biodiversity maintenance isn't merely an environmental concern but a practical disease-control strategy.
Read the full abstract on PubMed
Practical Takeaways
- •Understanding which wildlife species maintain disease reservoirs based on their biological characteristics can help predict disease risk in declining ecosystems
- •Habitat management preserving biodiversity may reduce transmission of vector-borne diseases by maintaining species with lower competence to carry pathogens
- •In areas where equine EEE is a concern, ecosystem changes favoring smaller clutch-size species could increase transmission risk
Key Findings
- •Species with larger body mass showed lower reservoir competence for Lyme disease and WNE hosts
- •Species with smaller clutch size had lower reservoir competence for EEE hosts
- •Life-history traits explain interspecific variation in pathogen reservoir competence across three vector-borne disease systems
- •As biodiversity decreases, species with higher reservoir competence are more likely to persist, increasing pathogen transmission risk (dilution effect mechanism)