Cambio estacional en la coloración dorsal de la lagartija Aspidoscelis costata costata (Squamata: Teiidae)
Oswaldo Hernández-Gallegos & Hublester Domínguez-Vega
ABSTRACT
Seasonal changes in the dorsal coloration in the lizard Aspidoscelis costata costata (Squamata: Teiidae). Color and color patterns in animals are important characteristics that bring protection, by dampening the ability of predators that depend on their sight to detect their preys. In lizards, the dorsal coloration plays a key role in communication of intraspecific signals such as social cues. In this study, we evaluated the seasonal changes in the dorsal coloration of the wide foraging lizard A. costata costata, in Tonatico, State of Mexico, Mexico. The seasonal evaluation included: the rainy season from mid June to mid September (can also include the end of May to early October); and the dry season for the rest of the year. The dorsal coloration of A. costata costata and their microhabitats were evaluated by contrasting the color pattern with an identification guide and the control colors of Pantone®, during 11 samplings carried out from February-October 2007. Individual lizard analysis recorded snout-vent length, sex and stage (juveniles and adults). Besides, all animals were marked by toe-clipping, allowing to distinguish dorsal coloration between seasons, sex and stage. A total of 95 lizards were analyzed (53 and 42 for the dry and rainy seasons respectively). We found that the dorsal coloration in A. costata costata varies seasonally and with microhabitats: during the dry season individuals show a brown coloration whereas during the rainy season becomes greener, as the background dominant vegetation color. The results of the present study suggest that: 1) the variation in dorsal coloration in A. costata costata plays an important role in the survival (by cryptic camouflage) of this widely foraging species; 2) the changes in the dorsal coloration of A. costata costata are individually expressed traits, since the coloration of the same lizard is either brown or green depending on the season; and 3) the cryptic functions of the dorsal coloration in widely foraging species have been largely underestimated. We discuss the possible influence of the changes in coloration in an habitat that changes drastically between both dry and rainy seasons.RESUMEN
En lagartijas la coloración corporal es importante en la comunicación así como en la protección contra los depredadores. Con el uso de una guía Pantone®, se analizó el cambio estacional en la coloración dorsal y los microhábitats de Aspidoscelis costata costata, una lagartija de amplio forrajeo que habita un ambiente (en el Estado de México, México) que cambia drásticamente de apariencia entre sequía y lluvias. Se analizó la dependencia de la coloración dorsal de acuerdo a la estación, sexo y estadio de desarrollo. Los resultados indican que la lagartija A. costata costata presenta una coloración dorsal similar al sustrato en cada estación: parda en sequía y principalmente verde en lluvias. Este estudio sugiere: 1) Que la variación en coloración dorsal con funciones crípticas, como la registrada en A. costata costata, puede resultar importante en la supervivencia de especies de amplio forrajeo; 2) Que el cambio en la coloración dorsal en A. costata costata es a nivel individual, ya que un individuo presente en ambas estaciones manifiesta una coloración dorsal parda en la estación de sequía y una coloración dorsal verde en la estación de lluvias y 3) Que la coloración dorsal, con funciones crípticas, está subestimada en especies de amplio forrajeo.