Abstract
Structures used in intrasexual competition span a continuum, with pure weapons that are used exclusively in physical fights at one extreme and pure aggressive signals that are used exclusively to assess and threaten rivals at the other. We propose this weapon-signal continuum offers a framework for understanding the variation in allometric slopes among intra-sexually selected structures. We predict allometric slopes will become steeper as the relative importance of signaling increases, because aggressive signaling will favor the evolution of hypervariable structures that facilitate the assessment of subtle differences in body size. We provide preliminary empirical support for the continuum hypothesis using species with different types of armaments and offer suggestions for how to test the weapon-signal continuum among closely related species.
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We thank Chrissie Painting and Emma Sherratt for the invitation to submit to this issue, and Daisuke Muramatsu, John Swallow, and Jerry Wilkinson for sharing their raw data.
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McCullough, E.L., O’Brien, D.M. Variation in allometry along the weapon-signal continuum. Evol Ecol 36, 591–604 (2022). https://doi.org/10.1007/s10682-022-10158-9
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DOI: https://doi.org/10.1007/s10682-022-10158-9