Abstract
Sexual ornaments, signalling individual quality to choosy females or rival males, often show steeper body size scaling compared with non-sexually selected traits. Theory posits such steeper body size scaling is the result of differential resource allocation, reflecting trade-offs between different components of fitness. Yet, the process of resource allocation towards body size-dependent sexual ornaments has been rarely understood empirically. Using the Neotropical territorial damselfly Megaloprepus caerulatus, whose males and females carry wax-based, sex-specific white wing bands and white wing tips respectively, we investigated nutrition sensitivity and body size scaling of both traits by manipulating larval food availability and directly quantified both the fat allocated to wing ornaments and the fat reserve from which allocations are made. Both colour traits exhibited sensitivity to food availability during larval development and steeper body size scaling compared with control traits. Although the absolute amount of fat invested in developing the colour ornaments increased with body size, the proportion of total fat allocated to the ornaments decreased with body size, making exaggerated ornaments less affordable for smaller individuals. Our data demonstrate that measuring the proportion of resource pool from which an individual's ornaments are derived (i.e. its affordability) is essential for understanding the maintenance of honesty of sexual signals.
Original language | English (US) |
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Pages (from-to) | 288-298 |
Number of pages | 11 |
Journal | Journal of evolutionary biology |
Volume | 35 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2022 |
Bibliographical note
Funding Information:This research was supported by a Smithsonian Institution Predoctoral Fellowship to M. Xu and by National Science Foundation grant IBN‐9408143 to O. M. Fincke. We are grateful to Sam Knewstub‐Brown, Kristen Olson and Caroline Winchester for assistance in rearing larvae. We thank the Smithsonian Tropical Research Institute for logistical support. Cornell University Statistical Consulting Unit provided advice in data analyses. We thank two anonymous reviewers whose comments have significantly improved this manuscript.
Funding Information:
This research was supported by a Smithsonian Institution Predoctoral Fellowship to M. Xu and by National Science Foundation grant IBN-9408143 to O. M. Fincke. We are grateful to Sam Knewstub-Brown, Kristen Olson and Caroline Winchester for assistance in rearing larvae. We thank the Smithsonian Tropical Research Institute for logistical support. Cornell University Statistical Consulting Unit provided advice in data analyses. We thank two anonymous reviewers whose comments have significantly improved this manuscript.
Publisher Copyright:
© 2021 European Society for Evolutionary Biology.
Keywords
- allometry
- damselfly
- differential cost
- handicap
- honest signal
- insect
- structural colour
- territorial contest
- trade-off
PubMed: MeSH publication types
- Journal Article
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.