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Abstract Animal signals evolve in an ecological context. Locally adapting animal sexual signals can be especially important for initiating or reinforcing reproductive isolation during the early stages of speciation. Previous studies have demonstrated that dewlap colour inAnolislizards can be highly variable between populations in relation to both biotic and abiotic adaptive drivers at relatively large geographical scales. Here, we investigated differentiation of dewlap colouration among habitat types at a small spatial scale, within multiple islands of the West Indies, to test the hypothesis that similar local adaptive processes occur over smaller spatial scales. We explored variation in dewlap colouration in the most widespread species of anole,Anolis sagrei, across three characteristic habitats spanning the Bahamas and the Cayman Islands, namely beach scrub, primary coppice forest and mangrove forest. Using reflectance spectrometry paired with supervised machine learning, we found significant differences in spectral properties of the dewlap between habitats within small islands, sometimes over very short distances. Passive divergence in dewlap phenotype associated with isolation‐by‐distance did not seem to explain our results. On the other hand, these habitat‐specific dewlap differences varied in magnitude and direction across islands, and thus, our primary test for adaptation—parallel responses across islands—was not supported. We suggest that neutral processes or selection could be involved in several ways, including sexual selection. Our results shed new light on the scale at which signal colour polymorphism can be maintained in the presence of gene flow, and the relative role of local adaptation and other processes in driving these patterns of dewlap colour variation across islands.
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This content will become publicly available on April 1, 2026
Leucistic Weddell seal ( Leptonychotes weddellii ) observations in Erebus Bay, Antarctica
Abstract Pigmentation and colouration are important to animal fitness. Colourations convey important information and impact predation risk, thermoregulation and mate selection. There are many cases of hypopigmentation across the animal kingdom, and leucism is a common form. We observed a Weddell seal (Leptonychotes weddellii) pup with cream-coloured fur, light skin and white nails multiple times in 2022 in Erebus Bay, Antarctica. The pup was observed 1 year later as a generally healthy yearling. This is the first documentation of a leucistic seal within this well-studied population and the second documentation of such colouration in this species. This seal offers a potential opportunity to observe the effects of hypopigmentation in Antarctic true seals.
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- Award ID(s):
- 2147553
- PAR ID:
- 10593025
- Publisher / Repository:
- Cambridge University Press
- Date Published:
- Journal Name:
- Antarctic Science
- Volume:
- 37
- Issue:
- 2
- ISSN:
- 0954-1020
- Page Range / eLocation ID:
- 117 to 121
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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