Ornaments indicate parasite load only if they are dynamic or parasites are contagious



Dougherty, Liam R ORCID: 0000-0003-1406-0680, Rovenolt, Faith, Luyet, Alexia, Jokela, Jukka and Stephenson, Jessica F
(2023) Ornaments indicate parasite load only if they are dynamic or parasites are contagious. EVOLUTION LETTERS, 7 (3). pp. 176-190.

Access the full-text of this item by clicking on the Open Access link.

Abstract

Choosing to mate with an infected partner has several potential fitness costs, including disease transmission and infection-induced reductions in fecundity and parental care. By instead choosing a mate with no, or few, parasites, animals avoid these costs and may also obtain resistance genes for offspring. Within a population, then, the quality of sexually selected ornaments on which mate choice is based should correlate negatively with the number of parasites with which a host is infected ("parasite load"). However, the hundreds of tests of this prediction yield positive, negative, or no correlation between parasite load and ornament quality. Here, we use phylogenetically controlled meta-analysis of 424 correlations from 142 studies on a wide range of host and parasite taxa to evaluate explanations for this ambiguity. We found that ornament quality is weakly negatively correlated with parasite load overall, but the relationship is more strongly negative among ornaments that can dynamically change in quality, such as behavioral displays and skin pigmentation, and thus can accurately reflect current parasite load. The relationship was also more strongly negative among parasites that can transmit during sex. Thus, the direct benefit of avoiding parasite transmission may be a key driver of parasite-mediated sexual selection. No other moderators, including methodological details and whether males exhibit parental care, explained the substantial heterogeneity in our data set. We hope to stimulate research that more inclusively considers the many and varied ways in which parasites, sexual selection, and epidemiology intersect.

Item Type: Article
Uncontrolled Keywords: sexual selection, epidemiology, host-parasite interactions, courtship behavior, sexual ornaments, meta-analysis
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User: Symplectic Admin
Date Deposited: 24 Jul 2023 15:17
Last Modified: 24 Jul 2023 15:17
DOI: 10.1093/evlett/qrad017
Open Access URL: https://academic.oup.com/evlett/article/7/3/176/71...
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3171826