First evidence of microfungal “extra oomph” in the invasive red swamp crayfish Procambarus clarkii

This paper represents the first attempt to study the microfungal flora contained in the digestive system of the most widespread aquatic invasive invertebrate in the world: Procambarus clarkii (Cambaridae, Decapoda). Understanding its bioinvasion, in terms of ecological risk and environmental impact, requires a multidisciplinary approach that considers consequences on all levels, from macroscopic to microscopic. In this study, we investigated both the population dynamics and the dietary habits of the red swamp crayfish captured within a natural biotope in Northern Italy. The diet was mainly based on plant detritus. The analysis of microfungal flora in the crayfish stomach revealed a fairly constant composition, unrelated to season and diet. Since most of the fungi were associated with detritus and some species were particularly frequent, we formulate the hypothesis that the fungi may be selected to decompose plant material in the digestive tract, thus providing a source of energy to the crayfish. Procambarus clarkii is also shown to be a potential vector of plant diseases as some of the 45 isolated fungal taxa are potentially phytopathogenic.