Lepidophyma gaigeae

Number of Pages: 4Integrative BiologyGeological Science

Pituophis ruthveni

Number of Pages: 16Geological SciencesIntegrative Biolog

Repeated evolution of blanched coloration in a lizard across independent white-sand habitats

The White Sands lizards of New Mexico are a rare and classic example of convergent evolution where three species have evolved blanched coloration on the white gypsum dunes. Until now, no geological replicate of the pattern had been described. However, one of the White Sands species, the lesser earless lizard (Holbrookia maculata), has been discovered to also inhabit the Salt Basin Dunes of Texas, where it has also evolved a blanched morph. We here present a first phenotypic and genetic description of the Salt Basin Dunes population of H. maculata. Phylogenetic inference based on a housekeeping gene (ND4) and a classic candidate gene in the melanin-synthesis pathway (Melanocortin 1 Receptor; Mc1r) shows the newly discovered population as an independent lineage, with no evidence of genetic parallelism in the coding region of Mc1r. Initial morphological data suggest that while this population displays convergent evolution in blanched coloration, there are divergent patterns in limb length and habitat use behavior between the gypsum environments. Our findings present the White Sands/Salt Basin Dunes as an exceptionally promising comparative model for studies of adaptation and convergent evolution

Do male barking geckos (Ptenopus garrulus garrulus) avoid refuges scented by other males?

Lizards frequently rely on chemical cues to detect the presence of a conspecific or a predator, or to sample and detect potential prey. Male lizards in particular, may chemically sample potential refuges to avoid rivals. We tested whether male common barking geckos (Ptenopus g. garrulus) that normally take refuge in burrows, avoid refuges scented with a rival male. Geckos were equally likely to use an artificial refuge scented by another male compared to a control. We conclude that scent is an unimportant cue for rival male recognition in P. g. garrulus based on 1) the result of this experiment; 2) during 510 man hours of field work we did not observe a single gecko tongue-flick; and 3) males respond aggressively to recordings of rival males and this appears to be the primary mechanism maintaining male spatial patterns.4 page(s

Shouting the odds : vocalization signals status in a lizard

Many species possess multiple sexually dimorphic traits, which incorporate different sensory modalities (e.g., acoustic, olfactory and visual), although their relative roles in sexual selection and in determining reproductive success are still poorly understood for most taxa. We assessed the role of multiple male traits, including one acoustic (dominant call frequency) and one visual (yellow throat patch) trait, in residency advertisement, contest behavior, and breeding success in barking geckos (Ptenopus garrulus garrulus). We show that male barking geckos maintain largely exclusive home ranges, with a trend for larger males to maintain larger home ranges. We also show that larger males have a lower dominant calling frequency. When aggressive behavior was elicited in the field using a recorded call of average frequency, resident males with low frequency calls were more likely to respond aggressively and charge the speaker compared to males with high frequency calls. However, body size and small relative throat patch size, rather than call frequency, were the best predictors of overall aggressiveness. Body size was also the best predictor of whether males bred. We suggest that call frequency in this crepuscular species constitutes an effective long-range signal of body size, used by males for remote rival assessment and to advertise home range boundaries in low-light environments.8 page(s

Spatial distribution and activity patterns in African barking geckos : implications for mating system and reproduction

We studied spatial clustering and activity patterns in the common Barking Gecko (Ptenopus garrulus garrulus) over the course of a breeding season in southern Africa. Only some populations exhibited significant clustering (two of six plots), suggesting that social and spatial organization varies according to factors such as population density and habitat. Clustering at our largest site was not influenced by soil temperature or prey availability, although burrow placement was significantly associated with vegetation coverage. We also examined the timing of the reproductive cycle by testing whether Barking Geckos exhibit protandry (male-first emergence). More males than females were active early in the breeding season and male territories were established before female emergence. Peak activity for 235 Barking Geckos at our primary study site was in late October, although males were significantly more active early in the season, consistent with the protandry model. The Barking Gecko mating system is most consistent with an iteroparous, harem polygynandry with an activity cycle that exhibits protandry. Our study highlights the importance of replicated spatial sampling for studies examining clustering and density effects on reproduction and mating systems.5 page(s

L. clamitans predator regime, morphology and swimming performance

ID = individuals tadpole identifier; Pond = Pond the tadpole originated from; Predator Community = The major predator type found the pond; Gosner Stage = Tadpoles developmental stage scored by Gosners (1960) method; Burst speed (cm/s) = Tadpole burst speed in cm per second; Columns L1X-LUniY = Tadpole morphometric scores (partial warps and uniform components, i.e. the weight matrix) for the lateral view of the tadpole; Columns D1X-DUniY = Tadpole morphometric scores (partial warps and uniform components, i.e. the weight matrix) for the dorsal view of the tadpole; log total CS = Tadpole size, i.e. log transformed total (summed) centroid size for the lateral and dorsal morphometric data