Meeting Abstract
Metabolic disease is not unique to vertebrates but occurs in natural populations of Libellula pulchella dragonflies and is caused by midgut-dwelling parasitic protozoan infections. This infection additionally causes impaired flight performance and energetics (and therefore reduced fitness) in male L. pulchella dragonflies, but little is known about the proximate mechanisms leading to these impairments, or what determines susceptibility to infection. Causative roles of infection in the development of metabolic disease are poorly understood in any animal system, nor have they often been explored within natural, ecological contexts. Here we present data that start addressing these issues in the L. pulchella system and that indicate that variation in soil type and surface water pH at different dragonfly collection sites strongly correlate with observed infection rates at these sites. In addition, we will present preliminary microbiome sequencing data analyses that suggest that microbial composition of the midgut of healthy male dragonflies varies by collection site. Moreover, midgut microbial community composition of infected male dragonflies appears to shifts towards a phenotype that resembles that observed in mammals suffering from metabolic disease. We hypothesize that susceptibility to infection is driven by environmental pH effects on the host midgut microbiome community, and will discuss our ongoing work addressing this hypothesis.
