Evolution of dorsal pattern variation in Greater AntilleanAnolislizards

Abstract

Dorsal patterning in animals can serve as an antipredator defence and may be involved in sexual selection, and is thus likely to be the target of multiple selective forces. Intraspecific variation in dorsal patterning is not rare, but the reasons behind it are poorly understood. Anolis lizards offer an ideal system to test for a role of ecological factors in driving variation in dorsal pattern. Anoles show a high degree of variation in dorsal pattern not only among species, but also between and within sexes. We use a comparative framework to explore whether ecological variables such as habitat use and perch height can explain the evolution of sexual dimorphism in dorsal pattern and the presence of female pattern polymorphism (FPP) in 36 Greater Antillean Anolis species. We provide evidence that anoles that perch closer to the ground are more likely to exhibit sexual dimorphism in dorsal pattern, and we suggest that habitat-use differences between sexes in ground-affiliated ecomorphs may drive the evolution of dorsal pattern dimorphism. In contrast, the ecological variables we investigated cannot explain the presence of FPP. Our results demonstrate that niche-associated diversification can generate phenotypic diversity within as well as among species, but the factors responsible for intrasexual polymorphism in some anole species remain cryptic.

Ecological, behavioral, and phylogenetic influences on the evolution of dorsal color pattern in geckos*

“…; Medina et al. ) but very little in geckos (Johnston and Bouskila ), so these topics could be a key subject for further investigation.…”

“…Furthermore, as this study focuses on color pattern used for camouflage and virtually all natural backgrounds are strongly UV-absorbing (foliage, earth, rocks, water, bark), we do not think ignoring potential UV reflectance is an issue for our analysis of camouflage patterning. Dorsal pattern polymorphism, sexual dichromatism, and rapid color change have been widely investigated in lizards (Paemelaere et al 2011;Medina et al 2016) but very little in geckos (Johnston and Bouskila 2007), so these topics could be a key subject for further investigation.…”

Testing background matching and disruptive colouration in a sexually dichromatic grasshopper: a computer detection experiment

“…This is especially important in organisms with high mobility (Stevens et al, 2006). Moreover, if females and males use distinct microhabitats owing to their different sexual roles, and/or display differences in mobility, natural selection can favour a divergence in cryptic colour patterns between females and males (Forsman & Appelqvist, 1999; Medina et al, 2016; Ramírez‐Delgado & Cueva del Castillo, 2020; Cueva del Castillo et al, 2021).…”

Background matching, disruptive coloration, and differential use of microhabitats in two neotropical grasshoppers with sexual dichromatism

“…Since crypsis reduces the probability of detection by predators, its variation usually matches geographic variation in substrate color (Endler, 1990;Hantak & Kuchta, 2018;Marshall, Philpot, Damas-Moreira, & Stevens, 2015;Rosenblum, 2006;Stuart-Fox & Ord, 2004). If females and males use different microhabitats, sexual dichromatism may evolve to better conceal them from visually oriented predators and could suggest differential crypsis values between sexes (Medina, Losos, & Mahler, 2016;Orton & McBrayer, 2019). Examples of crypsis mediating the coloration differences between females and males are found in many bird species.…”

“…However, in these cases, often females are cryptic because of predation pressures, whereas males are conspicuous due to sexual selection (Badyaev & Hill, 2003;Medina et al, 2017). Nonetheless, if females and males utilize different microhabitats, natural selection for crypsis can favor the divergence between females and males in dorsal cryptic color patterns (Forsman, 1995;Forsman & Appelqvist, 1999;Medina et al, 2016).…”