The thermoregulatory and reproductive behavior of the lesser earless lizard, <i>Holbrookia maculata</i>, at White Sands National Monument, New Mexico

TitleThe thermoregulatory and reproductive behavior of the lesser earless lizard, Holbrookia maculata, at White Sands National Monument, New Mexico
Publication TypeThesis
Year of Publication1998
AuthorsHager SB
Number of Pages128
Date Published1998
UniversityNew Mexico State University
CityLas Cruces, New Mexico
Thesis TypePh.D. Dissertationpp
Keywordsdissertation, dissertations, lizard, Holbrookia, lizard, physiology, lizard, thermoregulation, physiology, reptiles, theses, thesis, White Sands, lizard
AbstractThermoregulation and reproductive behavior were examined for the lesser earless lizard, Holbrookia maculata (Phrynosomatidae), in a series of field studies from 1994 to 1997 in southcentral New Mexico. Within the range of this species is a population that inhabits the unique environment of white gypsum (CaSO4) "sand" dunes at White Sands National Monument, New Mexico. The physical properties of gypsum produce soil temperatures that are relatively cooler than adjacent non-gypsum habitats. Lower environmental temperatures could ultimately influence body temperatures and this lizard's ability to successfully thermoregulate, forage, grow, mate, and escape predation. Given this, I hypothesized that White Sands H. maculata have lower body temperatures and use the environment in different ways than conspecifics in a non-gypsum habitat. The results of this study support to this hypothesis. White Sands lizards had significantly lower body temperatures than H. maculata from a "normally-colored" population, located at the Jornada Long-term Experimental Research site. The microhabitats in which lizards were first observed correlated with body temperatures at White Sands, but not at the Jornada. Coloration was examined in both White Sands and Jornada H. maculata. Results of this work support the conditional signal hypothesis that bright female coloration signals to males two temporally separated, discrete messages that are conditional upon the degree of coloration: early in the breeding season low intensity coloration signals courtship receptivity, whereas later in the season high intensity pigmentation signals courtship rejection. It also suggests that females (a) maximize the potential for egg fertilization by stimulating courtship with low intensity coloration when eggs are ready for fertilization, and (b) reject courtship with high intensity pigmentation when carrying fertilized eggs.