Life-history traits of two Mediterranean lizard populations: a possible example of countergradient covariation

Received: 1 October 2011 / Accepted: 27 September 2012 / Published online: 18 October 2012The trade-off between clutch and offspring size, which is a central topic in life-history research, is shaped by natural selection to maximize the number of surviving offspring, but it also depends on the resources available for reproduction. Conspecific populations living in different environments may differ in adult body size, clutch mass, clutch size, offspring size, and/or post-natal growth rates, due either to phenotypic plasticity or to local adaptation. Here, we compare these traits and their relationships between two populations of the lizard Psammodromus algirus separated by a 600-m altitudinal gradient. We used a common garden design to control incubation temperature and food availability, with two different feeding treatments. Females were larger at the high-elevation site. Although SVL-adjusted clutch mass did not differ between populations, high-elevation females laid more but smaller eggs than low-elevation ones. Hatchlings were larger at lower elevation. Our common garden experiment revealed that low-elevation hatchlings grewfaster than high-elevation hatchlings under both feeding treatments. However, higher food availability at higher altitude allows high-elevation lizards to grow faster and attain larger adult sizes, especially in the case of females. The two key adaptations of low-elevation lizards, large eggs and hatchlings and the ability to grow rapidly after hatching, are likely to enhance survival in low-productivity Mediterranean lowlands. Our data support the hypothesis that the reproductive strategies of these populations provide an example of countergradient variation, because the genotypes that encode for fast growth and large body size occurred in low food availability habitats where juveniles grewslowly and attained small adult sizes.This paper is a contribution to the projects CGL2007-60277/BOS and CGL2010-17928/BOS funded by the Spanish Ministry of Education and Science, and to the International Campus of Excellence (CEI Campus Moncloa) launched by Complutense University of Madrid (UCM) and Spanish Research Council (CSIC).Peer reviewe

There is more to the picture than meets the eye: adaptation for crypsis blurs phylogeographical structure in a lizard

Aim: We examined dorsal coloration in and genetic relationships among Iberian populations of the lizard Psammodromus algirus to determine the extent to which the current distribution of phenotypic variation is correlated with phylogeographical history or local environmental conditions. Location: Iberian Peninsula, western Palaearctic.Methods: We sequenced mitochondrial DNA (ND4 and adjacent tRNAs genes) in 36 populations, and seven microsatellite loci in eight representative populations. In 23 populations, lizards were classified according to the presence and intensity of a dorsal striped pattern, the heritability of which was estimated by means of mother–offspring regressions. To determine whether colour pattern is an adaptation for crypsis, we compared the time taken by humans to detect striped and unstriped lizards in different environments.Results: The analysis of mtDNA revealed an ancient split between a western clade, subdivided into south- and north-western haplogroups, and an eastern clade with central, south-eastern and eastern haplogroups. In contrast, nuclear markers showed a post-glacial admixture of central and western haplogroups, with the central haplogroup apparently isolated from the rest of its clade. This was consistent with variation in the dorsal striped pattern, a heritable phenotypic trait: central and western lizards were unstriped, whereas eastern lizards were striped. We then suggest that dorsal coloration promotes crypsis: in eastern locations detection times were longer for striped than for unstriped lizards, whereas the opposite was true in western and central locations.Main conclusions: Our results indicate that natural selection for crypsis may promote not only divergence within clades, as suggested by the apparent isolation between unstriped central lizards and striped members of eastern haplogroups, but also admixture between them. We conclude that ecologically driven selection is crucial for understanding the phylogeographical background of phenotypic variation, because recent adaptation to the environment can blur the effects of ancestral isolation.This study is a contribution to projects CGL2010-17928/BOS and CGL2013-41642-P, funded by the Spanish Ministry of Education and SciencePeer reviewe

¿Vamos a la Huerta? : Recuperación de saberes culturales alrededor de la producción agroecológica de alimentos

Con el avance de la agricultura industrial, los pueblos rurales fueron vaciados de saberes culturales, como es la autoproducción de alimentos. Gobernador Ugarte, ubicado en el partido de 25 de Mayo, provincia de Buenos Aires, Argentina, no escapa a esta problemática ambiental, social y cultural, agravada por el hecho de que no tiene verdulerías, que las pocas verduras y frutas que llegan son muy caras y; que la ciudad más próxima queda a 40km. Contrariamente a lo que se piensa en las ciudades, los vecinos no saben hacer huertas, porque se perdió la transmisión cultural de boca a oreja sobre la producción de alimentos. ¿Vamos a la Huerta?, es una propuesta lúdica y comunicacional para el aprendizaje de producción de hortalizas con bases agroecológicas, que se inició en el año 2008, y que realizan los alumnos del ciclo superior de la Escuela Secundaria, los cuales diseñan juegos para que los alumnos del nivel primario e inicial, recuperen dichos saberes desde una mirada interdisciplinar y reconstruyan la relación entre ciencias y saberes culturales.Eje: B5 Sistemas de conocimiento (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

¿Vamos a la Huerta? : Recuperación de saberes culturales alrededor de la producción agroecológica de alimentos

Con el avance de la agricultura industrial, los pueblos rurales fueron vaciados de saberes culturales, como es la autoproducción de alimentos. Gobernador Ugarte, ubicado en el partido de 25 de Mayo, provincia de Buenos Aires, Argentina, no escapa a esta problemática ambiental, social y cultural, agravada por el hecho de que no tiene verdulerías, que las pocas verduras y frutas que llegan son muy caras y; que la ciudad más próxima queda a 40km. Contrariamente a lo que se piensa en las ciudades, los vecinos no saben hacer huertas, porque se perdió la transmisión cultural de boca a oreja sobre la producción de alimentos. ¿Vamos a la Huerta?, es una propuesta lúdica y comunicacional para el aprendizaje de producción de hortalizas con bases agroecológicas, que se inició en el año 2008, y que realizan los alumnos del ciclo superior de la Escuela Secundaria, los cuales diseñan juegos para que los alumnos del nivel primario e inicial, recuperen dichos saberes desde una mirada interdisciplinar y reconstruyan la relación entre ciencias y saberes culturales.Eje: B5 Sistemas de conocimiento (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

¿Vamos a la Huerta? : Recuperación de saberes culturales alrededor de la producción agroecológica de alimentos

Con el avance de la agricultura industrial, los pueblos rurales fueron vaciados de saberes culturales, como es la autoproducción de alimentos. Gobernador Ugarte, ubicado en el partido de 25 de Mayo, provincia de Buenos Aires, Argentina, no escapa a esta problemática ambiental, social y cultural, agravada por el hecho de que no tiene verdulerías, que las pocas verduras y frutas que llegan son muy caras y; que la ciudad más próxima queda a 40km. Contrariamente a lo que se piensa en las ciudades, los vecinos no saben hacer huertas, porque se perdió la transmisión cultural de boca a oreja sobre la producción de alimentos. ¿Vamos a la Huerta?, es una propuesta lúdica y comunicacional para el aprendizaje de producción de hortalizas con bases agroecológicas, que se inició en el año 2008, y que realizan los alumnos del ciclo superior de la Escuela Secundaria, los cuales diseñan juegos para que los alumnos del nivel primario e inicial, recuperen dichos saberes desde una mirada interdisciplinar y reconstruyan la relación entre ciencias y saberes culturales.Eje: B5 Sistemas de conocimiento (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

Multi-omic detection of <i>Mycobacterium leprae</i> in archaeological human dental calculus

Mineralized dental plaque (calculus) has proven to be an excellent source of ancient biomolecules. Here we present a Mycobacterium leprae genome (6.6-fold), the causative agent of leprosy, recovered via shotgun sequencing of sixteenth-century human dental calculus from an individual from Trondheim, Norway. When phylogenetically placed, this genome falls in branch 3I among the diversity of other contemporary ancient strains from Northern Europe. Moreover, ancient mycobacterial peptides were retrieved via mass spectrometry-based proteomics, further validating the presence of the pathogen. Mycobacterium leprae can readily be detected in the oral cavity and associated mucosal membranes, which likely contributed to it being incorporated into this individual's dental calculus. This individual showed some possible, but not definitive, evidence of skeletal lesions associated with early-stage leprosy. This study is the first known example of successful multi-omics retrieval of M. leprae from archaeological dental calculus. Furthermore, we offer new insights into dental calculus as an alternative sample source to bones or teeth for detecting and molecularly characterizing M. leprae in individuals from the archaeological record.publishedVersio

The population genomic legacy of the second plague pandemic

SummaryHuman populations have been shaped by catastrophes that may have left long-lasting signatures in their genomes. One notable example is the second plague pandemic that entered Europe in ca. 1,347 CE and repeatedly returned for over 300 years, with typical village and town mortality estimated at 10%–40%.1 It is assumed that this high mortality affected the gene pools of these populations. First, local population crashes reduced genetic diversity. Second, a change in frequency is expected for sequence variants that may have affected survival or susceptibility to the etiologic agent (Yersinia pestis).2 Third, mass mortality might alter the local gene pools through its impact on subsequent migration patterns. We explored these factors using the Norwegian city of Trondheim as a model, by sequencing 54 genomes spanning three time periods: (1) prior to the plague striking Trondheim in 1,349 CE, (2) the 17th–19th century, and (3) the present. We find that the pandemic period shaped the gene pool by reducing long distance immigration, in particular from the British Isles, and inducing a bottleneck that reduced genetic diversity. Although we also observe an excess of large FST values at multiple loci in the genome, these are shaped by reference biases introduced by mapping our relatively low genome coverage degraded DNA to the reference genome. This implies that attempts to detect selection using ancient DNA (aDNA) datasets that vary by read length and depth of sequencing coverage may be particularly challenging until methods have been developed to account for the impact of differential reference bias on test statistics.Results and discussion STAR★Method

The macroecology of chemical communication in lizards: do climatic factors drive the evolution of signalling glands?

Chemical communication plays a pivotal role in shaping sexual and ecological interactions among animals. In lizards, fundamental mechanisms of sexual selection such as female mate choice have rarely been shown to be influenced by quantitative phenotypic traits (e.g., ornaments), while chemical signals have been found to potentially influence multiple forms of sexual and social interactions, including mate choice and territoriality. Chemical signals in lizards are secreted by glands primarily located on the edge of the cloacae (precloacal glands, PG) and thighs (femoral glands), and whose interspecific and interclade number ranges from 0 to >100. However, elucidating the factors underlying the evolution of such remarkable variation remains an elusive endeavour. Competing hypotheses suggest a dominant role for phylogenetic conservatism (i.e., species within clades share similar numbers of glands) or for natural selection (i.e., their adaptive diversification results in deviating numbers of glands from ancestors). Using the prolific Liolaemus lizard radiation from South America (where precloacal glands vary from 0-14), we present one of the largest-scale tests of both hypotheses to date. Based on climatic and phylogenetic modelling, we show a clear role for both phylogenetic inertia and adaptation underlying gland variation: (i) solar radiation, net primary productivity, topographic heterogeneity and precipitation range have a significant effect on number of PG variation, (ii) humid and cold environments tend to concentrate species with a higher number of glands, (iii) there is a strong phylogenetic signal that tends to conserve the number of PG within clades. Collectively, our study confirms that the inertia of niche conservatism can be broken down by the need of species facing different selection regimes to adjust their glands to suit the demands of their specific environments