Authors: Christopher H Martin Sönke Johnsen
Publish Date: 2007/07/07
Volume: 61, Issue: 12, Pages: 1897-1909
Abstract
The Hamilton–Zuk hypothesis proposes that females prefer male secondary sexual traits because they are honest indicators of parasite resistance Despite the attention that this hypothesis has received its role in sexual selection remains equivocal This study presents the first field test in guppies of two key predictions of the Hamilton–Zuk hypothesis 1 that within populations the most highly ornamented males have the fewest parasites and 2 that among populations males in high parasite populations have the most conspicuous ornaments Five hundred male guppies from 19 distinct populations in the Northern Range of Trinidad were inspected for Gyrodactylus parasites and photographed Eight measures of orange spot ornamentation were used to test the predictions hue saturation lightness relative area number and areaweighted hue saturation and lightness Parasite load had no significant effect on any of these measures There was also no relationship between orange spot ornamentation and parasite abundance among populations Guppies from highpredation environments had significantly more parasites and their orange coloration was lighter and less saturated than that in guppies from lowpredation environments Despite previous lab results this study found no relationship between parasite load and male orange spot ornamentationO Lau and R Hernandez provided excellent support with fieldwork in Trinidad K Hughes G Grether and H Rodd gave advice on project design and logistics S Alberts M Cummings K Hughes H Rodd W Morris T Getty and one anonymous reviewer offered valuable criticism of the manuscript K Hughes W Morris M Lavine D Stangl and G Puggioni were consulted on statistical analyses The Simla Research Station run by the ASA Wright Nature Center provided accommodation in Trinidad Trinidad’s Water and Sewage Authority generously allowed work in the Quare drainage This work was funded by a Summer Enrichment Grant from the Duke University Scholars Program a Latin American Studies Grant from the Mellon Foundation a Deans’ Summer Fellowship and the Undergraduate Research Support Program all at Duke University SJ was supported in part by a grant from the National Science Foundation IOB0444674 All protocols used in this study were approved by the Duke Institutional Animal Care and Use Committee registry A0780403 and comply with the current laws of Trinidad and Tobago
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