Larval ecomorphology of 13 Libellulidae (Anisoptera, Odonata) of the Middle Rio Doce Valley, Minas Gerais, Brazil

Abstract

In the lakes of the Middle Rio Doce, Minas Gerais (MG), two groups of larval Libellulidae are distinguished by preferences of habitat use: one uses mainly aquatic macrophytes and the other uses the bottom substrate. The goal of this work was to verify if there is a morphological distinction between the two groups of species. Thirteen body measures were taken from the larvae and analyzed. No difference was found between the two groups of species regarding the body size, but shape differences were observed for two morphological variables. The species that use mainly macrophytes tend to have larger relative measures of the labium and smaller measures of the abdomen width. Advantages in resource obtainment and in vulnerability to predation are probably the explanations for the morphological divergence among these larval groups.Keywords: Ecomorphology, Libellulidae, macrophyte, Rio Doce. Ecomorfologia larval de 13 Libellulidae (Anisoptera, Odonata) do Vale do Médio Rio Doce, MG, Brasil ResumoNos lagos do Médio Rio Doce (MG), dois grupos de larvas de Libellulidae apresentam diferenças no uso do habitat: um utiliza preferencialmente macrófitas aquáticas e o outro utiliza a superfície do fundo. O objetivo deste trabalho foi verificar se existe uma distinção morfológica entre estes dois grupos. Treze medidas morfológicas foram tiradas das larvas e analisadas. Nenhuma diferença, com relação ao tamanho corporal, foi encontrada entre os dois grupos, embora diferenças de forma tenham sido observadas com relação a duas variáveis morfológicas. As espécies que usam principalmente macrófitas tendem a possuir maiores medidas relativas do lábio e menores medidas da largura do abdome, o oposto ocorrendo com as larvas habitantes do fundo. Vantagens na captura de presas e na vulnerabilidade à predação são provavelmente as explicações para a divergência morfológica observada entre os dois grupos de larvas.Palavras-chave: Ecomorfologia, Libellulidae, macrófitas, Rio Doce.

Diversity of Odonata (Insecta) larvae in streams and farm ponds of a montane region in southern Brazil

“…Besides, the occurrence of odonates has been documented in less than one-third of the Brazilian territory, and especially in areas with tropical and subtropical climates (De Marco Junior & Vianna 2005). Additionally, bioecological studies have focused mainly on lakes and floodplains (De Marco Junior & Latini 1998, Franco & Takeda 2002, Fulan & Henry 2006, 2007, Juen et al 2007, Giacomini & De Marco Junior 2008, while main channels of lowland rivers (Ferreira-Peruquetti & De Marco Junior 2002, Assis et al 2004), montane streams (Dalzochio et al 2011), wetlands (Maltchik et al 2010), reservoir and fishfarms (De Marco Junior et al 1999, Fonseca et al 2004) are poorly known.…”

Phylogenetic Signal of Subsets of Morphological Characters: A Case Study in the Genus Erythemis (Anisoptera: Libellulidae)

“…For example, Johansson & Samuelson (1994) found that the action of predators might influence the length of dorsal and lateral thorns in Leucorrhinia dubia (Vander Linden, 1825) larvae. Giacomini & De Marco Jr. (2008) found a relationship among the variation of body length in larvae of several Anisoptera species and the habitat portion used by these. The authors stated that species like E. peruviana shows a narrower abdomen associated to the possibility of easy camouflage in macrophytes as a defense against predators.…”

“…The authors stated that species like E. peruviana shows a narrower abdomen associated to the possibility of easy camouflage in macrophytes as a defense against predators. According to Giacomini & De Marco Jr. (2008) the presence and reproduction of the organisms, is related to the variation of their morphology with the environment and its usage that they might do of their habitat. …”

Trait- and size-based descriptions of trophic links in freshwater food webs: current status and perspectives

“…The paradigm that morphology constrains the potential and realized niche, including habitat use and diet composition, has been central to ecomorphological studies of fishes (Webb, 1984;Wainwright, 1991;Sibbing and Nagelkerke, 2000). In other aquatic groups this approach has been followed rarely (Giacomini and De Marco, 2008;Rotheray, 2013) and has not lead to direct, quantitative links between morphological traits and diet. For example, Giacomini and De Marco (2008) found differences in body shape between similarly sized dragonfly larvae from the family Libellulidae that occupy either bottom substrate or aquatic macrophytes, but their study fell short of linking larval morphology to diet.…”

“…In other aquatic groups this approach has been followed rarely (Giacomini and De Marco, 2008;Rotheray, 2013) and has not lead to direct, quantitative links between morphological traits and diet. For example, Giacomini and De Marco (2008) found differences in body shape between similarly sized dragonfly larvae from the family Libellulidae that occupy either bottom substrate or aquatic macrophytes, but their study fell short of linking larval morphology to diet.…”