title: Temperature, but not available energy, affects the expression of a sexually selected ultraviolet (UV) colour trait in male European green lizards.
abstract: BACKGROUND
  Colour signals are widely used in intraspecific communication and often linked to individual fitness. The development of some pigment-based (e.g. carotenoids) colours is often environment-dependent and costly for the signaller, however, for structural colours (e.g. ultraviolet [UV]) this topic is poorly understood, especially in terrestrial ectothermic vertebrates.
  
  
  RESULTS
  In a factorial experiment, we studied how available energy and time at elevated body temperature affects the annual expression of the nuptial throat colour patch in male European green lizards (Lacerta viridis) after hibernation and before mating season. In this species, there is a female preference for males with high throat UV reflectance, and males with high UV reflectance are more likely to win fights. We found that (i) while food shortage decreased lizards' body condition, it did not affect colour development, and (ii) the available time for maintaining high body temperature affected the development of UV colour without affecting body condition or other colour traits.
  
  
  CONCLUSIONS
  Our results demonstrate that the expression of a sexually selected structural colour signal depends on the time at elevated body temperature affecting physiological performance but not on available energy gained from food per se in an ectothermic vertebrate. We suggest that the effect of high ambient temperature on UV colour in male L. viridis makes it an honest signal, because success in acquiring thermally favourable territories and/or effective behavioural thermoregulation can both be linked to individual quality.
authors.affiliation: Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary. cascadis@gmail.com
authors.forename: Katalin
authors.initials: K
authors.lastname: Bajer
authors.forename: Orsolya
authors.initials: O
authors.lastname: Molnár
authors.forename: János
authors.initials: J
authors.lastname: Török
authors.forename: Gábor
authors.initials: G
authors.lastname: Herczeg
mesh_terms: D000818:Animals; D001831:Body Temperature; D002149:Energy Intake; D005060:Europe; D005260:Female; D008116:Lizards / Q000502:physiology*; D008297:Male; D010858:Pigmentation; D010860:Pigments, Biological / Q000378:metabolism; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D010860:Pigments, Biological