Abstract
In heterogeneous habitats, camouflage via background matching can be challenging because visual characteristics can vary dramatically across small spatial scales. Additionally, temporal variation in signaling functions of coloration can affect crypsis, especially when animals use coloration seasonally for intraspecific signaling (e.g., mate selection). We currently have a poor understanding of how wild prey optimize background matching within continuously heterogeneous habitats, and whether this is affected by requirements of intraspecific signaling across biological seasons. Here, we quantified color patterns of a wild population of shore skink (Oligosoma smithi), a variably colored lizard endemic to New Zealand, to (a) investigate whether background matching varies across a vegetation gradient; (b) assess potential signaling functions of color; and (c) to determine whether there is a trade‐off between requirements for crypsis and intraspecific signaling in coloration across seasons. Although all pattern types occurred throughout the vegetation gradient, we found evidence for background matching in skinks across the vegetation gradient, where dorsal brightness and pattern complexity corresponded with the proportion of vegetation cover. There was also a significant disparity between ventral color (saturation) of juveniles and adults, and also between sexes, suggestive of sex recognition. However, there was little indication that color was condition‐dependent in adults. Despite some evidence for a potential role in signaling, crypsis did not greatly differ across seasons. Our study suggests that selection favors a mix of generalist and specialist background matching strategies across continuously heterogeneous habitats.
Highlights
Optimizing camouflage through background matching can be challenging for populations living in heterogeneous habitats, where visual characteristics of the background can vary across space and time
We have a poor understanding of how wild prey optimize background matching within continuously heterogeneous habitats, and whether this is affected by requirements of intraspecific signaling across biological seasons
Shore skink coloration at the coastal dunes of Tāwharanui showed spatial and temporal variation that is consistent with both crypsis and intraspecific signaling requirements
Summary
Optimizing camouflage through background matching can be challenging for populations living in heterogeneous habitats, where visual characteristics of the background can vary across space and time. When individuals are primarily restricted to a single background type either because of small home range or if habitat characteristics are too disparate from one another (e.g., brown vs green backgrounds), the population is expected to undergo disruptive selection for distinctive color pattern types (e.g., brown vs green morphs; Dale, 2006; Houston et al, 2007; Merilaita et al, 2001; Merilaita et al, 1999; Nilsson & Ripa, 2010) In such conditions, animals can achieve optimal background matching only in one background type (specialist strategy), resulting in a discrete spatial distribution of color pattern variants across the site. Background matching may not be significantly affected if coloration for intraspecific signaling is only on ventral regions
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