Article

Vitamin E Supplementation Increases the Attractiveness of Males' Scent for Female European Green Lizards

Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary.
PLoS ONE (Impact Factor: 3.23). 04/2011; 6(4):e19410. DOI: 10.1371/journal.pone.0019410
Source: PubMed

ABSTRACT

In spite that chemoreception is important in sexual selection for many animals, such as reptiles, the mechanisms that confer reliability to chemical signals are relatively unknown. European green lizards (Lacerta viridis) have substantial amounts of α-tocopherol ( = vitamin E) in their femoral secretions. Because vitamin E is metabolically important and can only be attained from the diet, its secretion is assumed to be costly. However, its role in intraspecific communication is unknown.
Here, we experimentally show that male European green lizards that received a dietary supplement of vitamin E increased proportions of vitamin E in their femoral secretions. Furthermore, our experiments revealed that females preferred to use areas scent marked by males with experimentally increased vitamin E levels in their secretions. Finally, female preferences were stronger when vitamin E differences between a pair of males' secretions were larger.
Our results demonstrate that female green lizards are able to discriminate between males based on the vitamin E content of the males' femoral secretions. We suggest that the possible cost of allocating vitamin E to secretions, which might be dependent on male quality, may be a mechanism that confers reliability to scent marks of green lizards and allows their evolution as sexual signals.

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    • "If it is costly to allocate dietary acquired compounds, such as oleic acid or tocopherol to secretions, deviating them from their important metabolic functions, males may use secretion of these compounds to signal their conditiondependent quality (Martín and L opez, 2015). Similarly, in some lacertid lizards, males that allocate more oleic acid (Martín and L opez, 2010b) or more tocopherol (Kopena et al., 2011) to secretions , are those in a better health condition and/or with a diet of higher quality, and their scents are more attractive to females. In contrast, females would not need to signal their quality to males in this way and could avoid secreting these costly compounds. "
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    ABSTRACT: Many lizards use femoral gland secretions in intraspecific chemical communication, but specific compounds have been identified in only a few species. Chemical composition of secretions may depend on phylogeny, but it may also evolve to maximize efficacy of signals in a given environment. In deserts, the extreme dry and hot environmental conditions are hostile for chemical signals and, therefore, we expected desert lizards to have secretions with highly stable compounds. Using GC–MS, we identified 74 lipophilic compounds in femoral secretions of male and female spiny-tailed lizards, Uromastyx aegyptia microlepis (Fam. Agamidae), from the Qatar desert. Compounds included mainly steroids and fatty acids, but also terpenoids, ketones, tocopherol, aldehydes and alcohols. We found differences between males and females; males had higher proportions of fatty acids and tocopherol, but lower proportions of ketones than females. Contrary to expectations, the most abundant compounds were not stable in the desert climatic conditions at the surface. However, secretions could be rather adapted to microclimatic conditions inside burrows where these lizards spend long periods of time. We suggest that in addition to phylogenetic and environmental characteristics, we should know the ecology of a lizard species before making generalizations on the potential characteristics of its chemical signals.
    No preview · Article · Apr 2016 · Journal of Arid Environments
    • "Diet supplementation of α-tocopherol (= vitamin E) results in increased proportions of vitamin E in femoral gland secretions of male green lizards, Lacerta viridis and L. shreiberi (Kopena et al., 2011, 2014). This relationship between diet and secretions is important because vitamin E is the main compound in secretions of green lizards (Kopena et al., 2009; López and Martín, 2006), and females seem to prefer areas scent-marked by males with large proportions of vitamin E in secretions (Kopena et al., 2011), suggesting that this compound may function as a chemosignal probably indicating the quality of the male (i.e. the ability to obtain or select food of high quality) or his territory (i.e. the availability of high quality food within it). Within the organism, vitamin E is the main lipophilic antioxidant and radical scavenger involved in membrane defense and immuno stimulatory activity (Brigelius-Flohe and Traber, 1999). "
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    ABSTRACT: Many lizards have diverse glands that produce chemosignals used in intraspecific communication and that can have reproductive consequences. For example, information in chemosignals of male lizards can be used in intrasexual competition to identify and assess the fighting potential or dominance status of rival males either indirectly through territorial scent-marks or during agonistic encounters. Moreover, females of several lizard species "prefer" to establish or spend more time on areas scent marked by males with compounds signaling a better health or body condition or a higher genetic compatibility, which can have consequences for their mating success and inter-sexual selection processes. We review here recent studies that suggest that the information content of chemosignals of lizards may be reliable because several physiological and endocrine processes would regulate the proportions of chemical compounds available for gland secretions. Because chemosignals are produced by the organism or come from the diet, they should reflect physiological changes, such as different hormonal levels (e.g. testosterone or corticosterone) or different health states (e.g. parasitic infections, immune response), and reflect the quality of the diet of an individual. More importantly, some compounds that may function as chemosignals also have other important functions in the organism (e.g. as antioxidants or regulating the immune system), so there could be trade-offs between allocating these compounds to attending physiological needs or to produce costly sexual "chemical ornaments". All these factors may contribute to maintain chemosignals as condition-dependent sexual signals, which can inform conspecifics on the characteristics and state of the sender and allow to make behavioral decisions with reproductive consequences. To understand the evolution of chemical secretions of lizards as sexual signals and their relevance in reproduction, future studies should examine what information the signals are carrying, the physiological processes that can maintain the reliability of the message and how diverse behavioral responses to chemosignals may influence reproductive success.
    No preview · Article · Feb 2015 · Hormones and Behavior
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    • "In many lizard species, males exude femoral pore secretions. The compounds present within these secretions may provide information on aspects of male quality, such as immunocompetence [27] and health [30]. In addition, females may also be capable of discriminating among male color morphs by femoral pore secretions alone [31]. "
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    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.
    Full-text · Article · Jul 2014 · PLoS ONE
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