Dispersal and resistance to starvation in Raoiella indica (Acari: Tenuipalpidae).

Raoiella indica Hirst (Tenuipalpidae) is an obligate phytophagous mite that has rapidly colonized wide areas of tropical America and causes severe injuries, mainly to plants in the families Arecaceae, Heliconiaceae, Zingiberaceae and Musaceae. This study evaluates biological attributes of the species that could explain its potential as invasive pest, its capacity to survive when deprived of food and its dispersal mechanisms, including passive displacement by wind and possible phoretic association with insects. This mite has a higher resistance to starvation than other phytophagous mites, with a maximum 12 days for adult females. Its main dispersal is by wind, even at low velocities. Phoresy on insects was not observed.

The impact of global warming on the range distribution of different climatic groups of Aspidoscelis costata costata.

The ectothermic nature of reptiles makes them especially sensitive to global warming. Although climate change and its implications are a frequent topic of detailed studies, most of these studies are carried out without making a distinction between populations. Here we present the first study of an Aspidoscelis species that evaluates the effects of global warming on its distribution using ecological niche modeling. The aims of our study were (1) to understand whether predicted warmer climatic conditions affect the geographic potential distribution of different climatic groups of Aspidoscelis costata costata and (2) to identify potential altitudinal changes of these groups under global warming. We used the maximum entropy species distribution model (MaxEnt) to project the potential distributions expected for the years 2020, 2050, and 2080 under a single simulated climatic scenario. Our analysis suggests that some climatic groups of Aspidoscelis costata costata will exhibit reductions and in others expansions in their distribution, with potential upward shifts toward higher elevation in response to climate warming. Different climatic groups were revealed in our analysis that subsequently showed heterogeneous responses to climatic change illustrating the complex nature of species geographic responses to environmental change and the importance of modeling climatic or geographic groups and/or populations instead of the entire species' range treated as a homogeneous entity.

Three new species of Xiphocentron Brauer, 1870 (Trichoptera, Xiphocentronidae) from Mexico.

Three new species of the genus Xiphocentron (Trichoptera, Xiphocentronidae) are described from Nearctic and Neotropical regions of Mexico. Xiphocentron (Glyphocentron) flinti sp. nov. has a very unique morphology distinguished by the presence of long spines on the preapical and apical margin of tergum X. Xiphocentron (Antillotrichia) holzenthali sp. nov. is diagnosed by tergum IX, with the apical margin bearing a narrow, rounded, mesal emargination and by a spiny projection near the basal plate. These species are the first records of the family in northwestern Mexico. Xiphocentron (Antillotrichia) pineroi sp. nov. is recognized, when observed in lateral view, by its less elongate genitalia and the sinuous mesal sclerite of the inferior appendage. Additionally, we provide detailed illustrations of Xiphocentron (Antillotrichia) rhamnes Schmid, and an updated list of the distribution of the genus Xiphocentron in Mexico.

Does size matter? An analysis of the niche width and vulnerability to climate change of fourteen species of the genus Crotalus from North America.

The niche comprises the set of abiotic and biotic environmental conditions in which a species can live. Consequently, those species that present broader niches are expected to be more tolerant to changes in climatic variations than those species that present reduced niches. In this study, we estimate the amplitude of the climatic niche of fourteen species of rattlesnakes of the genus Crotalus to evaluate whether those species that present broader niches are less susceptible to the loss of climatically suitable zones due to the projected climate change for the time period 2021-2040. Our results suggest that for the species under study, the breadth of the niche is not a factor that determines their vulnerability to climatic variations. However, 71.4% of the species will experience increasingly inadequate habitat conditions, mainly due to the increase in temperature and the contribution that this variable has in the creation of climatically suitable zones for most of these species.

Densidad, idoneidad ambiental y nicho ecológico de cuatro especies de felinos americanos (Carnivora: Felidae)

Varias de las especies silvestres de la familia Felidae se encuentran en riesgo y el tamaño poblacional es uno de los parámetros ecológicos más importantes para determinar acciones efectivas de conservación. El tamaño poblacional está determinado por diferentes factores, tanto bióticos como abióticos, que en conjunto satisfacen los requerimientos de los individuos para sobrevivir y reproducirse, permitiendo la permanencia de las especies a través del tiempo. Debido a que el tamaño poblacional de una especie no es homogéneo a lo largo de su distribución, se han formulado varias hipótesis para explicar sus variaciones. Una propuesta considera que las poblaciones más grandes se ubican en las regiones con mayor idoneidad ambiental y el número de individuos decrece hacia las menos favorables. Otra hipótesis considera que el tamaño poblacional está relacionado con la estructura interna del nicho ecológico, en donde las poblaciones más grandes están ubicadas en el centroide del nicho y el tamaño declina conforme aumenta la distancia a éste. El objetivo de este estudio fue evaluar la relación de la abundancia poblacional con la idoneidad ambiental y el nicho ecológico en cuatro especies de felinos silvestres de América. La densidad de Lynx rufus (lince) se correlacionó positivamente con el índice de idoneidad ambiental, la mayor densidad de Panthera onca (jaguar) se ubicó en regiones cercanas al centroide del nicho, mientras que las densidades poblacionales de Leopardus pardalis (ocelote) y de Puma concolor (puma) no se ajustaron a las predicciones de ninguna de las dos hipótesis. La relación entre densidad de felinos con las características ambientales puede ser especie-específica y no seguir un patrón generalizado.

Several wild species of the family Felidae are at risk, and population size is one of the most important ecological parameters to determine conservation actions. Population size is influenced by different biotic and abiotic factors that satisfy the requirements of the species to survive and reproduce, allowing the permanence of the species through time. Because population size is not homogeneous throughout the distribution, there are several hypotheses to explain their variations. One proposal considers that more abundant populations are located in regions with environmentally suitability, and population size decreases towards the less favorable ones. Another hypothesis considers that the population size is related to the internal structure of the ecological niche, where the largest populations are located in the centroid of the niche, and the size declines as the distance to this centroid increase. The objective of this study was to evaluate the relationship between population abundance, environmental suitability and ecological niche in four wild felids species of America. The density of Lynx rufus (bobcat) was correlated positively with the environmental suitability index, the highest density of Panthera onca (jaguar) was located in regions near the centroid of the niche, while the population densities of Leopardus pardalis (ocelot) and Puma concolor (cougar) did not conform to the predictions of either of the two hypotheses. The relationship between feline density and environmental characteristics was species-specific, with no general pattern.