Population dynamics of an epibiont Ostracoda on the invasive red swamp crayfish Procambarus clarkii in a western Mediterranean wetland

Recently, the American entocytherid ostracod Ankylocythere sinuosa was discovered for the first time in Europe to inhabit widely distributed populations of the invasive American crayfish Procambarus clarkii in the Iberian Peninsula. Based on this finding, the aim was to describe the population dynamics of exotic entocytherids for the first time beyond their original area, and to analyse the main variables modulating temporal demographic patterns. We monitored a population of A. sinuosa and its host, P. clarkii , in the Pego-Oliva wetland (Eastern Iberian Peninsula) monthly for 1 year. Crayfish entocytherid loads strongly related to crayfish weight, moult-related exoskeleton hardening stage and water temperature. The proportion of earliest juvenile entocytherid instars, an indicator of recent hatching periods, also related to water temperature and conductivity. According to our results, the most important factors affecting entocytherid dynamics are individual crayfish moulting events, which diminish ostracod load, together with water temperature and ionic concentration, both influencing the life cycle of the exotic epibiont ostracod A. sinuosa .