Food selection by Plumatella geimermassardi Wood and Okamura, 2004 (Phylactolaemata, Bryozoa)

Bryozoans are sessile filter feeding organisms able to play an important role in the cycling of organic matter in freshwater ecosystems. However, the quality and quantity of food particles ingested by bryozoans are still not well-known. Therefore, an experimental design was performed in order to investigate the clearance rate (CR), food selection and efficiency of assimilation by the freshwater bryozoan species Plumatella geimermassardi. P. geimermassardi was collected from the Colfiorito Marsh (Umbrian Natural Park, Italy), during summer. A higher grazing rate of suspended and dissolved solids was evidenced in the colonies collected in June, July, than in August. Food selection and assimilation of phytoplankton were determined. The algal species ingested as diet food item and those excreted with the faecal pellets were taxonomically identified. The results provide new information on CR and food selection by P. geimermassardi and enhance knowledge on its biology. Insights on feeding preferences by bryozoan species can provide valid information about their feasible distribution and abundance

Food selection by

Bryozoans are sessile filter feeding organisms able to play an important role in the cycling of organic matter in freshwater ecosystems. However, the quality and quantity of food particles ingested by bryozoans are still not well-known. Therefore, an experimental design was performed in order to investigate the clearance rate (CR), food selection and efficiency of assimilation by the freshwater bryozoan species Plumatella geimermassardi. P. geimermassardi was collected from the Colfiorito Marsh (Umbrian Natural Park, Italy), during summer. A higher grazing rate of suspended and dissolved solids was evidenced in the colonies collected in June, July, than in August. Food selection and assimilation of phytoplankton were determined. The algal species ingested as diet food item and those excreted with the faecal pellets were taxonomically identified. The results provide new information on CR and food selection by P. geimermassardi and enhance knowledge on its biology. Insights on feeding preferences by bryozoan species can provide valid information about their feasible distribution and abundance

Phylogenetic Diversity of the Red Swamp Crayfish <i>Procambarus clarkii</i> and Its Dispersal Pattern in Northern and Central Italy

The red swamp crayfish Procambarus clarkii is one of the most threatening freshwater species in the world. The aim of this study is to provide a better understanding of the phylogeography and the invasion routes of P. clarkii populations in the Italian Peninsula through the analysis of mitochondrial phylogeny. Mitochondrial control region and cytochrome c oxidase subunit I (COI) sequences of 153 samples collected from six Italian basins were analyzed and compared to worldwide data. Except for the lakes Bolsena and Posta Fibreno, a high genetic variability was found in the other basins. The mitochondrial DNA pattern of P. clarkii from the lakes Candia and Massaciuccoli confirmed the hypothesis of double introduction events. Another entry point could be represented by Lake Trasimeno, which shows haplotypes originating from Louisiana and not shared with other Italian basins. Moreover, unique lineages were also found in the Stella River, thus enhancing the hypothesis that multiple introductions of P. clarkii occurred in northern and Central Italy and strengthening the idea that knowledge about the dispersion routes of this alien species can be useful to predict its invasiveness and elaborate control strategies to preserve biodiversity

Population Ecology and Genetic Diversity of the Invasive Alien Species Procambarus clarkii in Lake Trasimeno (Italy)

The deliberate or accidental introduction of invasive alien species (IAS) causes negative ecological and economic impacts altering ecosystem processes, imperiling native species and causing damage to human endeavors. A monthly monitoring program was performed in Lake Trasimeno (Central Italy) from July 2018 to July 2019 in order to provide an upgrade of the population ecology of Procambarus clarkii and to assess the genetic diversity by analyzing the relationships among mitochondrial DNA diversity. Our results confirmed that P. clarkii is well acclimatized in the lake, revealing a stable population structure favored by the resources and conditions typical of this ecosystem, which seem to be optimal for the maintenance of the species. Four distinct mitochondrial haplotypes were detected, but one of them was clearly overrepresented (76%), suggesting that a single predominant introduction event may have occurred in this area, likely followed by secondary events. The identification of the typical genetic variants provides a better understanding of the evolutionary scenarios of P. clarkii in this biotope and it can be helpful in management plans concerning the expanding populations of this invasive alien species