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Environmental pressures challenge the survivorship of wildlife, and adaptive ability is key to their success and establishment. However, it remains unclear how changes in environmental conditions affect the phenotypic plasticity of some species. Studies that consider the effect of the environment (e.g., climate changes) on species morphology are essential to better understand his potential resilience. Thus, Diptera species appear as an excellent model. Here we investigated the effect of environmental conditions on wing size and shape within and between one native and one invasive blowfly species populations, along an ecoregional gradient in Brazil. For native species, wing size was affected by almost all environmental variables, while wing shape was unaffected. For invasive species, humidity best explained both wing size and wing shape variation. Our results show a differentiation between populations for both species, but a transversal comparison reveals that invasive species do not seem to be affected in the same way as the native species by climatic variations in the field. Temperature and humidity are the most significant environmental variables associated with differences in wing size and shape for invasive species, indicating an elevated climate tolerance of this species, which may be associated with its invasive characteristics and adaptive potential. Thus, our findings shed light on the importance of assessing the individual and compound effect of environmental variation and biological invasion on the adaptation of native species, since it is expected to increase 3 °C with a 20% overall reduction in the amount of rainfall in the tropical region of Brazil by 2100. [ABSTRACT FROM AUTHOR]

The Water Opossum, Chironectes minimus (Didelphimorphia, Didelphidae), is the only semi-aquatic marsupial and can be easily identified for its uniquely patterned water resistant pelage and webbed hind-feet. The species is distributed along the Neotropical region (from Southern Mexico to Northwestern Argentina) and is currently divided on four subspecies ( C.   m. argyrodytes, C. m. panamensis, C. m. minimus, C. m. paraguensis ), based on its geographical distribution. We evaluated the geographic variation in C. minimus , using traditional and geometric morphometrics techniques to capture the size and shape of the skull to identify differences between the populations that could relate to existing subpsecies or populations that and would merit particular taxonomic attention. We took 13 skull measurements, and digitized 37, 18, and 23 2D landmarks on the dorsal and lateral view of the cranium and on the lateral view of the mandible, respectively. The sample consisted on 135 individuals from 66 localities. Analyses of both datasets showed that the Southern South America and Northern Central America animals differ from the other populations. Geometric morphometrics shows on the three views that the Amazon animals differ from the others probably due to existing geographical barriers. These morphological differences among populations of the Water Opossum support the need for a proper phylogenetic assessment of these populations, in order to clarify their taxonomic status. [ABSTRACT FROM AUTHOR]