TY - JOUR
T1 - Geographic variation in sexual selection among populations of an iguanid lizard, Sauromalus obesus (=ater)
AU - Kwiatkowski, Matthew A.
AU - Sullivan, Brian
N1 - Funding Information:
We are grateful to Fundaqgo para a Cikncia e a Tecnologia (POCTI, Quadro Comunitario de Apoio 111) for financial support. We also thank Prof. Regina Tavares, Dr. Adklia Dinis and Dr. Teresa Vasconcelos for collection and identification of the plant. We are also grateful to Mr. IdalCcio Marques and Dr. Joaquim Marqalo for mass spectra.
PY - 2002/10/1
Y1 - 2002/10/1
N2 - Geographic variation in selection pressures may result in population divergence and speciation, especially if sexual selection varies among populations. Yet spatial variation in targets and intensity of sexual selection is well studied in only a few species. Even more rare are simultaneous studies of multiple populations combining observations from natural settings with controlled behavioral experiments. We investigated how sexual selection varies among populations of the chuckwalla, Sauromalus obesus. Chuckwallas are sexually dimorphic in color, and males vary in coloration among populations. Using field observations and multiple regression techniques, we investigated how sexual selection acts on various male traits in three populations in which males differed in coloration. The influence of sexual selection on male coloration was then investigated in more detail using controlled experiments. Results from field observations indicate that phenotypic selection was acting on territory quality in all three populations. In two populations, selection was also acting either directly or indirectly on male coloration. Male color likely functions as an indicator of food resources to females because male color is based partly on carotenoid pigments. In controlled experiments, significantly more females from these two populations chose males with brighter colors over dull males, a result consistent with studies on carotenoid pigments in other taxa. In a third population, no evidence of sexual selection on male coloration was found in either the field study or controlled experiment. Lack of female preferences for male color in this population, in which chuckwalla densities are low and home ranges are large, may result from searching costs to females.
AB - Geographic variation in selection pressures may result in population divergence and speciation, especially if sexual selection varies among populations. Yet spatial variation in targets and intensity of sexual selection is well studied in only a few species. Even more rare are simultaneous studies of multiple populations combining observations from natural settings with controlled behavioral experiments. We investigated how sexual selection varies among populations of the chuckwalla, Sauromalus obesus. Chuckwallas are sexually dimorphic in color, and males vary in coloration among populations. Using field observations and multiple regression techniques, we investigated how sexual selection acts on various male traits in three populations in which males differed in coloration. The influence of sexual selection on male coloration was then investigated in more detail using controlled experiments. Results from field observations indicate that phenotypic selection was acting on territory quality in all three populations. In two populations, selection was also acting either directly or indirectly on male coloration. Male color likely functions as an indicator of food resources to females because male color is based partly on carotenoid pigments. In controlled experiments, significantly more females from these two populations chose males with brighter colors over dull males, a result consistent with studies on carotenoid pigments in other taxa. In a third population, no evidence of sexual selection on male coloration was found in either the field study or controlled experiment. Lack of female preferences for male color in this population, in which chuckwalla densities are low and home ranges are large, may result from searching costs to females.
KW - Chuckwalla
KW - Geographic variation
KW - Mate preferences
KW - Population variation
KW - Sauromalus obesus
KW - Sexual selection
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U2 - 10.1111/j.0014-3820.2002.tb00130.x
DO - 10.1111/j.0014-3820.2002.tb00130.x
M3 - Article
C2 - 12449491
AN - SCOPUS:0036807176
SN - 0014-3820
VL - 56
SP - 2039
EP - 2051
JO - Evolution
JF - Evolution
IS - 10
ER -