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Factors driving the spatial patterns of communities of sedentary organisms are still poorly understood. In this context parthenogenetic animals are useful to test the contribution of sexual and interspecific interactions on spatial patterns. As such, mixed communities of asexual and sexual species are expected to be spatially organized as a single sexual species, with sexes randomly distributed and mutually independent. During the reproductive period, we determined the instantaneous spatial structure in a community of Darevskia rock lizards from Armenia composed of one sexual species (D. valentini), two asexual species (D. armeniaca, D. unisexualis), and their hybrids. We also analysed the specific composition of clusters and the species segregation by habitat. We used the Ripley's K distance function to measure clustering spatial patterns, and the Delaunay's triangulation to identify the clusters and their specific composition. We estimated the spatial segregation among species by calculating the overlap between species pairs, by comparing pairwise distances from males to other males and from males to females, and by comparing the frequencies of both sexes and reproduction modes (asexual and sexual) in plant cover and height using log-linear models. Species displayed a clustered spatial structure, with parthenogens (mainly D. armeniaca) or their hybrids in all clusters. Females and males were concentrated in areas with medium plant cover. D. armeniaca and D. valentini were the species with the highest overlap. Males were closer to males than to females. This community displays an instantaneous spatial pattern resembling a population of a single sexual species. Spatial statistics offer new insights to analyse the spatial structure of species communities. [ABSTRACT FROM AUTHOR]

Several Caucasian rock lizards of the genus Darevskia of hybrid origin are known to reproduce parthenogenetically. Local communities can be composed exclusively of parthenogens, though syntopy with bisexual members of the genus may occur. In some localities, reproduction between bisexual and parthenogenetic Darevskia has been previously reported based on lizard intermediate morphology and karyology (3n, 4n). However, the frequency of such heterospecific matings remains unknown. We indirectly quantified the reproductive interactions through the inspection of copulation marks in females in a mixed Darevskia community from Kuchak (Armenia) composed of two hybrid parthenogens (D. armeniaca and D. unisexualis), one bisexual species (D. valentini) and their putative backcrosses. A total of 139 adults were randomly collected and photographed. Females were later measured (SVL), inspected for inguinal marks and ranked from 0 (no scars) to 3 (= 3 scars). The lizard species and ploidy determination was ensured by a parallel microsatellite analysis. Sex-ratio in the community was extremely biased due to the high abundance of parthenogenetic females. All female types displayed copulation marks with frequencies varying from 80% in D. valentini to 64% in D. armeniaca. Remarkably, 7 out of 11 (64%) backcross females also showed marks. In the most abundant D. armeniaca, the prevalence and intensity of copulation marks increased with body size, just as predicted for polygynous female lacertids. These results indicate that copulation between parthenogenetic and bisexual species in Darevskia mixed communities is common and driven by sexual selection, thus reinforcing previous suggestions of reproductive interaction in syntopy. Evolutionary implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

We assessed whether ecophysiological requirements are consistent with the environmental traits within the current ranges in a relictual lizard group, Algyroides, composed of four species with restricted and disjunctive distributions. We considered temperature, precipitation and their seasonal profiles, and focused on the preferred body temperature (Tp) and the evaporative water loss (EWL). The ranges of all four species differed in environmental traits. The two geographically more restricted species followed divergent patterns: A. moreoticus inhabits hot and climatically buffered areas, and A. marchi occupies cold seasonal environments. Tp and EWL also differed among species following a geographical grouping: A. nigropunctatus (Slovenia) and A. fitzingeri (Sardinia) selected for lower Tp and lost less water than the southern species A. moreoticus (Peloponnese) and A. marchi (Southern Spain). Tp and EWL were correlated at species level but not at individual level within species. Results suggest that the current distribution of Algyroides species partly reflects their ecophysiology, with water ecology taking precedence over thermal ecology as constraining factor. By unravelling the environmental factors limiting the distribution of species, ecophysiology may provide directions for conservation, predicting the degree of vulnerability to climate change. [ABSTRACT FROM AUTHOR]