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Sexual selection operates by acting on variation in mating success. However, since selection acts on whole-organism manifestations (i.e., performance) of underlying morphological traits, tests for phenotypic effects of sexual selection should consider whole-animal performance as a substrate for sexual selection. Previous studies have revealed positive(More)
Tail removal from dominant juvenile Uta stansburiana resulted in a decrease in social status in dyadic encounters. Most lizards were affected after removal of two-thirds of their tails. In some pairs, dominant lizards lost status after removal of one-third of their tails but regained dominance after the other member of the pair lost two-thirds of its tail.(More)
Atelognathus patagonicus is an endangered leptodactylid frog endemic to a small region in and around Laguna Blanca National Park in northern Patagonia, Argentina. All of the lakes and small ponds of the region (except Laguna Blanca itself) contain A. patagonicus and in all but one of these lakes the species shows clinical signs of a previously undiagnosed(More)
To understand how selection acts on performance capacity, the ecological role of the performance trait being measured must be determined. Knowing if and when an animal uses maximal performance capacity may give insight into what specific selective pressures may be acting on performance, because individuals are expected to use close to maximal capacity only(More)
Tail autotomy is a defense against predators used by many lizard species but is associated with various costs, most of which have been measured only in the laboratory. We conducted a field experiment in which we induced tail autotomy to approximately half (58%) of a marked sample (n=326) of Uta stansburiana from western Texas in the fall, and left the other(More)
The Texas horned lizard (Phrynosoma cornutum) is protected in several states due to its apparently declining numbers; information on its physiology is therefore of interest from both comparative endocrine and applied perspectives. We collected blood samples from free-ranging P. cornutum in Oklahoma from April to September 2005, spanning their complete(More)
The approximately 28,300 species of tetrapods (four-limbed vertebrates) almost exclusively have perennial life spans. Here, we report the discovery of a remarkable annual tetrapod from the arid southwest of Madagascar: the chameleon Furcifer labordi, with a posthatching life span of just 4-5 months. At the start of the active season (November), an age(More)