Black fly (Diptera:Simuliidae) larvae body size variation along an altitude gradient in the Itatiaia National Park, Brazil

Abstract

According to Bergmann’s Rule, individuals who inhabit higher altitudes tend to be larger in body mass or size, when compared with individuals of the same taxon who inhabit lower altitude places. Black flies are insects of great medical and veterinary importance due to its blood-sucking habit, becoming subject of studies regarding its bionomics, ecology and taxonomy. Studies approaching the influence of the altitude gradient in the morphology of Diptera: Simuliidae larvae are scarce in the literature, therefore, this study aimed to investigate the influence of altitude gradient in the morphology of Diptera: Simullidae larvae in Itatiaia National Park, RJ, and thus verify if Bergmann’s Rule is applicable to these organisms. Black fly larvae were sampled from four sites during periods of March and May 2013. From each site 30 larvae were measured, and these lengths were later compared between sites using Kruskal-Wallis, which showed a significant difference (P<.05) among sites from lower altitudes in relation to those of higher elevations, what was corroborated using a cluster analysis. The altitude was related to larval size using a linear regression, showing a positive correlation between these variables, thus corroborating Bergmann’s rule for Black flies.