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

Laura Garzoli,Anna Picco,Daniele Paganelli,Dario Savini,Mattia Moretto,Anna Occhipinti-Ambrogi,Marinella Rodolfi

doi:10.3391/ai.2014.9.1.04

Abstract

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.

Highlights

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. We investigated both the population dynamics and the dietary habits of the red swamp crayfish captured within a natural biotope in Northern Italy
The red swamp crayfish Procambarus clarkii (Girard, 1852) is one of the top 27 alien species of animals to have been introduced into Europe for aquaculture (Savini et al 2010), and is considered to be one of the most dangerous species in terms of ecological risk and environmental impact (Geiger et al 2005; Gherardi and Acquistapace 2007; Tricarico et al 2010)
The highest mean CPUE value of P. clarkii was registered in summer (AVCPUE in July 2009=2.67±2.09), while the lowest was registered in winter (AVCPUE in February 2010=1.3±0.67) (Figure 2)

Summary

Introduction

P. clarkii is a North American native species (Huner 1988), due to its outstanding performances in aquaculture productivity, it was legally introduced into southern Spain in 1973, and later illegally introduced into most other European countries between 1970 and 1990 (SoutyGrosset et al 2006) Many biological traits, such as the capability to live out of water for long periods (Gherardi and Barbaresi 2007), a high reproductive potential (Aquiloni et al 2010; Barbaresi and Gherardi 2006; Savini 2007), and tolerance to environmental pollution (Aquiloni et al 2011), are responsible for the rapid spread of crayfish in the wild. In Italy, Procambarus clarkii appeared in the wild for the first time in 1989 in the river Banna, a tributary of the Po river, after escaping from an experimental farm (Delmastro 1992); its distribution currently includes the majority of the northern and central regions, as well as the islands (Gherardi et al 1999a; Chiesa et al 2006; Savini and Occhipinti 2008; Scalici et al 2009; Aquiloni et al 2011), and it has been recorded on several occasions in southern Italy (Morpugo et al 2010)

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