Species' Life-History Traits Explain Interspecific Variation in Reservoir Competence: A Possible Mechanism Underlying the Dilution Effect

Zheng Y X Huang,Frank Van Langevelde,Tim M Blackburn,Herbert H T Prins,Willem F De Boer,Valerie Olson,Bradley S Schneider

doi:10.1371/journal.pone.0054341

Abstract

Hosts species for multi-host pathogens show considerable variation in the species' reservoir competence, which is usually used to measure species' potential to maintain and transmit these pathogens. Although accumulating research has proposed a trade-off between life-history strategies and immune defences, only a few studies extended this to host species' reservoir competence. Using a phylogenetic comparative approach, we studied the relationships between some species' life-history traits and reservoir competence in three emerging infectious vector-borne disease systems, namely Lyme disease, West Nile Encephalitis (WNE) and Eastern Equine Encephalitis (EEE). The results showed that interspecific variation in reservoir competence could be partly explained by the species' life histories. Species with larger body mass (for hosts of Lyme disease and WNE) or smaller clutch size (for hosts of EEE) had a higher reservoir competence. Given that both larger body mass and smaller clutch size were linked to higher extinction risk of local populations, our study suggests that with decreasing biodiversity, species with a higher reservoir competence are more likely to remain in the community, and thereby increase the risk of transmitting these pathogens, which might be a possible mechanism underlying the dilution effect.

Highlights

Diseases caused by multi-host pathogens are able to impact livestock productivity, agricultural economies, wildlife conservation and public health [1]
We present a quantitative study relating life-history traits to the variation in species’ reservoir competence for three vector-borne diseases: one tick-borne disease, Lyme disease and two mosquito transmitted diseases, West Nile Encephalitis (WNE) and Eastern Equine Encephalitis (EEE)
Our study focused on the relationships between life-history traits and species’ reservoir competence for three vector-borne diseases

Summary

Introduction

Diseases caused by multi-host pathogens are able to impact livestock productivity, agricultural economies, wildlife conservation and public health [1]. Only a few studies extended this trait-based approach to examine the relationships between the hosts’ life-history traits and the potential to transmit pathogens (but see Cronin et al [2]) Better understanding these relationships could help us to predict the species’ reservoir competence and model disease dynamics at community level, which is relevant for human health, economic growth and wildlife conservation [1,2,7]. Since the morphological and physiological traits of species which regulate interactions with pathogens are usually phylogenetically conserved [16], phylogenetic differences in reservoir competence may exist across different taxa [3] We use both a conventional and a phylogenetic comparative analysis to test the relationships between the life-history traits and reservoir competence. We expect reservoir competence to be negatively correlated with body mass and incubation time (gestation time for mammals) while positively correlated with clutch size (litter size for mammals)

Materials and Methods

Results

Findings

Discussion