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The Northern raccoon Procyon lotor is a native mesocarnivore of North America which has been introduced to many Eurasian countries, where invasive populations currently occur. Regarding Italy, the species is present in Lombardy and in the Foreste Casentinesi National Park (Tuscany and Emilia-Romagna). In this work, we conducted a review on food habits of the Northern raccoon both in the native and in the introduced ranges, and we firstly reported the evidence on the impact of this species on native crayfish in Central Italy. We retrieved 18 papers published between 1932 and 2020, 14 from the native range and four from the invasive range. We analysed the frequency of occurrence of nine food categories (mammals, birds, reptiles, amphibians, fish, insects, crustaceans, fruits, and others). After fruits, crustaceans (where available) were the main food items detected in raccoon scats (up to 60% of the total diet, in the frequency of occurrence). In September 2019, we detected a total of 37 dead adult freshwater white-clawed crayfish Austropotamobius pallipes complex in Central Italy, with evident signs of predation by the Northern raccoon. The local population of Northern raccoon is fast expanding its range, whereas the local population of A. pallipes complex is declining. This crayfish species is protected by national and international laws. Thus, a monitoring program involving all stakeholders and institutions dealing with in environmental management, aiming at removing all raccoons currently present in this area of Central Italy, should be carried out in the short term to limit the potential impacts exerted by the fast-spreading of this invasive mammal. [ABSTRACT FROM AUTHOR]

The microsporidiosis of the endangered white-clawed crayfish Austropotamobius pallipes complex has generally been attributed to only one species, Thelohania contejeani , the agent of porcelain disease. Species identification was mostly assessed by macroscopic examination or microscopic evaluation of muscle samples rather than by molecular or ultrastructural analyses. A survey conducted on A. pallipes complex populations in Northern Italy highlighted the presence of two different microsporidia causing similar muscular lesions, T. contejeani and an undescribed octosporoblastic species Vairimorpha austropotamobii sp. nov. Mature spores and earlier developmental stages of V. austropotamobii sp. nov. were found within striated muscle cells of the thorax, abdomen, and appendages of the crayfish. Only octosporoblastic sporogony within sporophorous vesicles (SPVs) was observed. Diplokaryotic sporonts separated into two uninucleate daughter cells, which gave rise to a rosette-shaped plasmodium, and eight uninucleate spores were produced within the persistent SPV. Ultrastructural features of stages in the octosporoblastic sequence were similar to those described for Vairimorpha necatrix , the type species. Mature spores were pyriform in shape and an average of 3.9 × 2.2 µm in size. The polar filament was coiled 11–14 times, lateral to the posterior vacuole. The small subunit ribosomal RNA gene (SSU rRNA) and the large subunit RNA polymerase II gene (RPB1) of V. austropotamobii sp. nov. were sequenced and compared with other microsporidia. The highest sequence identity of SSU rRNA (99%) and RPB1 (74%) genes was with the amphipod parasite Nosema granulosis and subsequently with V. cheracis , which infects the Australian yabby Cherax destructor. In our work we discuss about the reasons for placing this new species in the genus Vairimorpha . In addition, we provide for T. contejeani a RPB1 gene sequence, supplemental sequences of SSU rRNA gene and ultrastructural details of its sporogony in the host A. pallipes complex. [ABSTRACT FROM AUTHOR]

Cases of co-occurrence among freshwater decapods are few. In their European range, the crab Potamon fluviatile and the white-clawed crayfish Austropotamobius pallipes complex do not usually share the same stream section or pond even if they live in sympatry, suggesting a strong segregation of the two species. The coexistence was hypothesized during the Pleistocene era, but without evidence of recent contact between them. The co-occurrence of these two species (i.e., occupying a common area) is reported in a stream of the Central Italy, being the first case in Italy and in Europe. To assess this co-occurrence, in 2015 we investigated three transects (only crabs, only crayfish and both species), collecting biotic and abiotic data. The three transects were similar for canopy cover, substrate composition and density of potential shelters (but not for the abiotic parameters), and characterized by a good water quality and abundance of preys, being suitable for the two species. No agonistic behavioural patterns have been observed, leading to hypothesize that co-occurrence may be favoured by the slightly smaller size of crayfish and crabs in the shared area than the size of animals in the other transects or by the different microhabitats chosen by crayfish and crabs when sharing the same stream section. Other possible explanations are discussed here, but further studies are necessary to better understand the co-occurrence of these two native crustaceans. Moreover, urgent measures are demanded to guarantee the survival of these protected species hampered by several threats. [ABSTRACT FROM AUTHOR]

This is a study of movements and artificial shelters use by a 3-year established population of Austropotamobius pallipes complex, in a lentic environment in the Parco Lombardo della Valle del Ticino (NW Italy). Home-checking and mark-recapture methods were used to investigate movements of 178 crayfish and shelter use by 389 crayfish in summer and in autumn. Most crayfish (97.2%) moved but the movement was highly variable. The greater part of the distances moved was less than 10 m day-1. Multi-hole bricks with one opening have been mostly selected, and the lower level was preferentially occupied; frequently a single crayfish per brick was found. The animal's size affected the majority of the analysed variables: mean daily distance, area fidelity, level of shelter; on the other hand no case was significant for sex. The results highlight that this species is fairly mobile and could colonize waterbodies with similar features even rather rapidly. Mobility does not appear to affect the endangered status of this species. [ABSTRACT FROM AUTHOR]