Fluctuating asymmetry as a tool for assessing development stability on small mammals from the Argentine agroecosystem

MARTINI, GASTÓN ANDRÉS; CODA, JOSÉ; PRIOTTO, JOSÉ W

Congreso; II Virtual Meeting of Systematics, Biogeography, and Evolution: The Research of Biodiversity and the Diversity of Researchers; 2021

Evolutionary biologists have not paid as extensive attention to nongenetic components of variation as they have done to genetic variation of phenotypic traits. Generally, nongenetic components are grouped in categories such as the ?environmental variation?. However, they differ in both their origin and biological significance. Individuals experience different environmental conditions resulting in phenotypic plasticity. Therefore, it is necessary to consider the developmental system and how it produces variation in phenotypic traits. Developmental instability (DI) results from random variation during development, which produces deviations in each developing structure from expected for both genotype and environment. Fluctuating asymmetry (FA), defined as small random deviations of perfect bilateral symmetry, has been suggested as a good DI estimator. Recently, agricultural activity has increased, being one of the key causes of habitat destruction and subsequent biodiversity loss. Thus, we evaluated the effect of agricultural intensification through local and landscape variables on DI (skulls and jaws) of individuals of three rodent species. Landscape variables were recorded: area perimeter ratio (PA) and habitat diversity index. The local variable was vegetation volume (Vv) of habitat edge. We used individuals housed in the UNRC-Mammal Collection caught during 2016 in the central-Argentine agroecosystem. Type I and II landmarks were digitized in 2D images. Asymmetric shape components were extracted using geometric morphometrics. For the analysis, GLM were generated, using the AIC-Criterion to select them. No associations between explanatory variables and FA were found in Akodon azarae and Calomys musculinus skulls. A negative association of FA with PA and Vv was observed in C. venustus skull. No associations with the explanatory variables were found for any of the species? mandibles. The study shows a disparity in morphological responses, depending on whether the skull or the mandible is analyzed. The results are discussed based on the degree of habitat requirements of the species.