Group Living, Parental Care, Age Structure, and Genetic Relatedness in Liolaemus leopardinus, a High-elevation Lizard from the Andes of Chile

Social behavior refers to any interactions between two or more conspecifics. A relatively common social behavior in the animal kingdom is group living, which provides benefits to group members (e.g., enhanced vigilance and predation avoidance). Predation risk is an important force that selects for behavioral traits, and promotes the evolution of sociality favored by kin selection. Most studies of sociality have focused on animal groups in which interactions are overtly obvious. Although interactions differ among the various vertebrate lineages, taxa are often categorized as social or non-social, ignoring the diversity and complexity of social behavior. Reptiles have been usually labeled as non-social; however, the degree of sociality can vary among species as shown in the genus Egernia. Liolaemus leopardinus is a high-elevation lizard species endemic to the Chilean Andes. It is viviparous, lives in large colonies, and adults and juveniles are highly social, but little is known about the natural history of the species. Our findings over two field seasons suggest that bird predation causes mothers of L. leopardinus to engage in parental behavior, and that predation by birds forces newborns of the species to behave secretively and to seek solitary refuge underneath rocks partially covered by bushes. Skeletochronology revealed the formation of annual growth rings in the phalangeal bones of subjects of L. leopardinus; however, the method was poorly suited for aging individuals. However, when body size of various free-ranging subjects repeatedly captured and measured was plotted against activity periods of three years, we could assign individuals to four age groups, and estimated the age when female lizards became sexually mature. We provide spatial, behavioral, and genetic evidence that supports the conclusion that L. leopardinus forms social groups of closely related individuals with non-relatives mixed in. Genetically related juveniles and adults spend time in close association, share home ranges and communal refuges during the day and night, and overwinter together in deep rock crevices. As a whole, our study revealed fine details regarding the gregarious behavior of L. leopardinus, a social but highly secretive species. We suggest that predation, kin recognition, and roosting drive the evolution of sociality in L. leopardinus, and not thermoregulation, refuge availability, or food.Zoolog

Age estimation through skeletochronology and mark-recapture of free-living Liolaemus leopardinus (Squamata: Liolaemidae) from Chile

Estimativa etária por meio de esqueletocronologia e marcação-e-recaptura de Liolaemus leopardinus (Squamata: Liolaemidae) do Chile. A determinação etária é um componente crucial de estudos ecológicos. Pesquisadores tem usado diferentes técnicas e métodos como marcação-erecaptura, tamanho do corpo e esqueletocronologia, para avaliar a idade de indivíduos na natureza. Usamos esses três métodos para estimar a estrutura etária de uma população de Liolaemus leopardinus, uma espécie de lagarto saxícola, altamente social e endêmica da região temperada do centro do Chile. Essa espécie secretiva de grandes altitudes é considerada ameaçada, e apesar dos esforços para descobrir detalhes específcos sobre a sua história natural, detalhes cruciais de sua biologia permanecem desconhecidos. Nosso objetivo foi associar o número de Linhas de Crescimento (LAGs) ao comprimento rostro-cloacal (SVL) e usar as LAGs para representar uma estimativa etária dos indivíduos na natureza. Para as análises de esqueletocronologia, foi coletada uma combinação de cortes de artelhos quando cada indivíduo foi capturado pela primeira vez em 2012–2013. O SVL de todos os indivíduos capturados foi registrado durante duas campanhas consecutivas (primavera a outono de 2011–2012 e 2012–2013). Os dados de SVL estiveram também disponíveis para 10 indivíduos coletados anteriormente e marcados de forma permanante em 2005 (um juvenil e nove adultos) e recapturados em 2011–2012. Três daqueles 10 indivíduos foram capturados novamente em 2012–2013. Nossos resultados revelaram a formação de LAGs em L. leopardinus e um alto grau de remodelação óssea tanto nos junevis como nos adultos. Essa remodelação ósssea combinada com a alta aproximação das LAGs periféricas nas amostras dos lagartos mais velhos sugere que os ossos das falanges não são adequados para a determinação etária nessa espécie. Por outro lado, nossos resultados de marcação-e-recaptura permitiram classifcar os indivíduos em quatro diferentes classes etárias quando o SVL de um indivíduo era associado com os períodos de atividade e recapturas. Indivíduos de L. leopardinus são longevos, podendo exceder uma década. As fêmeas tornam-se sexualmente maduras aos três ou quatro anos de idade.Age estimation through skeletochronology and mark-recapture of free-living Liolaemus leopardinus (Squamata: Liolaemidae) from Chile. Age determination is a crucial component of ecological studies. Researchers have relied on different methods and techniques, for example mark-recapture, body size, and skeletochronology, to assess the age of free-ranging individuals. We used all three methods to estimate the age structure of a population of Liolaemus leopardinus, a highly social and saxicolous lizard species endemic to the temperate region of central Chile. This high-elevation and secretive species is considered threatened and, although efforts have been made to reveal more specifc details about the species’ natural history, crucial details of its biology are still unknown. Our goal was to associate the number of Lines of Arrested Growth (LAGs) to snout–vent length (SVL) and use LAGs as an age estimation proxy on free-ranging individuals. For the skeletochronology analyses, a combination of toe-clips was collected when each subject was frst captured in 2012–2013. SVL for all captured individuals was recorded during two different feld seasons (austral spring to fall of 2011–2012 and 2012–2013). SVL data were also available for 10 individuals initially collected and permanently marked in 2005 (one juvenile and nine adults) and recaptured in 2011–2012. Three of those 10 subjects were captured again in 2012–2013. Our results revealed the formation of LAGs in L. leopardinus and a high degree of bone remodeling in both juveniles and adults. This bone remodeling combined with the high rapprochement in peripheral LAGs on the samples of the oldest lizards suggest that phalangeal bones are not suitable for age determination in this species. On the other hand, our mark-recapture results allowed us to assign individuals to four different age-classes when a subject’s SVL was associated with activity periods and recaptures. Individuals of L. leopardinus are long-lived and their lifespan can exceed a decade. Female lizards become sexually mature at three to four years of age

Reparto de recursos de los gremios de lagartijas en el cañón de Chínipas, Chihuahua, México

We studied the resource partitioning of time and space in lizard assemblages in three different plant associations (tropical deciduous forest [BTC], oak forest [BE], and pine forest [BP]) located in Chínipas’ Canyon, Chihuahua, in which we observed sixteen lizard species of ten genera. The niche overlap was determined using Pianka’s index while Simpson’s formula was used for the calculation of the niche breadth. The results indicate that the niche overlap index values, per species pair, are generally lower than Ojk = 0.50. However, for the pseudo communities, generated with the survey information gathered from topical deciduous forests and pine forests, statistical values were obtained that suggest the existence of potential competition in regards to resource time in each vegetation association. The niche breadth values indicate that the individuals tend to be specialists when using time resource and generalists when using resource space. Sceloporus clarkii was the only species recorded in the three plant associations.Se estudió el reparto de dos recursos -espacio y tiempo- entre los ensambles de lagartijas en tres asociaciones vegetales (bosque tropical caducifolio [BTC], bosque de encino [BE] y bosque de pino [BP]) en el Cañón de Chínipas, Chihuahua, en las que en conjunto se observaron dieciséis especies de diez géneros. El traslape de nicho se evaluó utilizando el índice Pianka y la amplitud de nicho al emplear la fórmula de Simpson. Los resultados indican que los valores del índice de traslape de nicho, por pares de especies, por lo general son menores a Ojk = 0.50. Sin embargo, para las pseudocomunidades de lagartijas generadas con la información recabada en el BTC y la del BP sí se obtuvieron valores estadísticos que sugieren la presencia de la posible competencia respecto al recurso tiempo. Al evaluar los valores de amplitud de nicho indican que los individuos estudiados tienden a ser especialistas al utilizar el recurso tiempo y generalistas en cuanto al espacio. Sceloporus clarkii fue la única especie registrada en las tres asociaciones vegetales

Conocimiento, uso y valor cultural de seis presas del jaguar (Panthera onca) y su relación con éste, en San Nicolás de los Montes, San Luis Potosí, Mexico Knowledge, use and cultural value of six prey of jaguar (Panthera onca) and their relationship with this species in San Nicolás de los Montes, San Luis Potosí, Mexico

Durante 2007 se obtuvo información del conocimiento y la percepción que los pobladores del ejido tienen sobre el jaguar, sus presas y los factores que afectan la distribución y su conservación. Mediante el índice de importancia cultural (IIC) se determinó el conocimiento que los ejidatarios tienen de las presas, y el uso y valor que les otorgan. Las presas que reconocieron importantes fueron venado cola blanca (Odocoileus virginianus), temazate (Mazama temama), pecarí (Tayassu pecari), tejón (Nasua narica), armadillo (Dasypus novemcinctus) y tepezcuintle (Cuniculus paca); 72% de los encuestados también identificaron especies domésticas como presas del jaguar. Según su percepción, las más abundantes son pecarí, tejón y armadillo. El valor de uso más importante es el alimenticio, puesto que 82% de los encuestados ha consumido alguna especie silvestre. El valor más alto del IIC fue para el venado (27.17). En el ejido se considera perjudicial el jaguar por alimentarse del ganado. Los pobladores y los jaguares utilizan las mismas especies para obtener beneficio. El presente estudio constituye una base para el desarrollo de trabajos tendientes a manejar y conservar los recursos naturales que existen en el ejido considerando las necesidades de la población humana, de su fauna silvestre y la relación entre éstas.During 2007, we obtained information about the knowledge, perception of rural people regarding jaguar, its preys and the factors that affect its distribution and conservation. Additionally, we determined with the Index of Cultural Importance the knowledge, use and value that rural people assign to preys of the jaguar. They recognized as important prey species of the jaguar to white-tailed deer (Odocoileus virginianus), brocket (Mazama temama), pecari (Tayassu peccari), coati (Nasua narica), armadillo (Dasypus novemcinctus) and paca (Cuniculus paca). Most of the villagers (72%) identified also domestic species as preys of the jaguar. According to villager´s perception, the more abundant species were pecari, coati and armadillo. Wildlife use for food was the most important since 82% of the interviewed people have consumed some species. The highest value of Cultural Importance was for white tailed deer (27.17). Jaguars in the ejido are considered harmful animals since they prey on livestock. Rural people and jaguars benefit from same wildlife species. The present study is the framework to develop future projects focused on managing and conserving natural resources that exist in the ejido San Nicolás de los Montes, San Luis Potosí