Preference for Male Traits Differ in Two Female Morphs of the Tree Lizard, Urosaurus ornatus

Abstract

Non-random female mating preferences may contribute to the maintenance of phenotypic variation in color polymorphic species. However, the effect of female preference depends on the types of male traits used as signals by receptive females. If preference signals derive from discrete male traits (i.e., morph-specific), female preferences may rapidly fix to a morph. However, female preference signals may also include condition-dependent male traits. In this scenario, female preference may differ depending on the social context (i.e., male morph availability). Male tree lizards (Urosaurus ornatus) exhibit a dewlap color polymorphism that covaries with mating behavior. Blue morph males are aggressive and defend territories, yellow males are less aggressive and defend smaller territories, and orange males are typically nomadic. Female U. ornatus are also polymorphic in dewlap color, but the covariation between dewlap color and female behavior is unknown. We performed an experiment to determine how female mate choice depends on the visual and chemical signals produced by males. We also tested whether female morphs differ in their preferences for these signals. Female preferences involved both male dewlap color and size of the ventral color patch. However, the female morphs responded to these signals differently and depended on the choice between the types of male morphs. Our experiment revealed that females may be capable of distinguishing among the male morphs using chemical signals alone. Yellow females exhibit preferences based on both chemical and visual signals, which may be a strategy to avoid ultra-dominant males. In contrast, orange females may prefer dominant males. We conclude that female U. ornatus morphs differ in mating behavior. Our findings also provide evidence for a chemical polymorphism among male lizards in femoral pore secretions.

Common Wall Lizard Females (Podarcis muralis) do not Actively Choose Males Based on their Colour Morph

“…), with the only exception being the tree lizard (Lattanzio et al. ). In this species polymorphic males adopt different territorial strategies, and females choose males accordingly: yellow females exhibit preference to avoid ultra‐dominant males, whereas orange females prefer dominant ones.…”

“…However, the female morphs of tree lizards responded to visual and chemical signals differently, and were capable of distinguishing among the male morphs using chemical signals alone (Lattanzio et al. ). Actually, our experiments showed that females were more interested by scents rather than colour of males, thus revealing that they probably assessed information conveyed by gland secretions.…”

“…; Lattanzio et al. ). For example, Uta stansburiana females did not mate assortatively according to colour morphs, but followed flexible mate choice rules according to population density (Alonzo & Sinervo ).…”

“…Furthermore, Lattanzio et al. () recently found that Urosaurus ornatus females actually discriminate male partners, but mate preference did not relate with the colour of male dewlap, but rather with the secretions of their femoral pores.…”

Natural selection favors local specialization in a widespread habitat generalist

“…Specifically, a previous mate choice study revealed no impact of male size on female preference (Lattanzio et al. ) and, although male body size may covary with aggressiveness among habitats (Lattanzio and Miles ), it is not the best indicator of competitive ability in U. ornatus (Carpenter ).…”