Aumento de assimetria flutuante induzido por rejeito de mineração em Smicridea (Rhyacophylax) coronata (Trichoptera)

Abstract

The Samarco/Vale/BHP mine tailing dam breach occurred in Minas Gerais, southeastern Brazil, in 2015, depositing high concentrations of metals and metalloids in the Doce river basin and severely impacting freshwater ecosystems. To assess developmental instability of caddisflies in response to the environmental impacts of the dam breach, we investigated fluctuating asymmetry (FA) in the species Smicridea (Rhyacophylax) coronata (Trichoptera: Hydropsychidae). FA was assessed at individual and populational scales using geometric morphometric methods in the cephalic capsule and mandibles of larvae and also on the forewings of adults, both belonging to the impacted condition (IC) and least disturbed condition (LDC). The levels of FA increased in response to stressors on the forewings at a populational scale, and on the mandibles, at individual scale. These morphological variations in the larval and adult stages may lead to detrimental effects and result in high mortality rates as well as lower adult fitness. Trichoptera forewings are revealed as suitable traits for assessing FA, holding potential for applications in biomonitoring programs. Our results validate the relationship between the impacts from the Fundão dam breach and increased developmental instability in this species. We hypothesize that negative correlations between FA levels and environmental impacts can be explained by the legacy effect in the Doce river basin.