Environment and host-related factors modulate gut and carapace bacterial diversity of the invasive red swamp crayfish (Procambarus clarkii)

The invasive red swamp crayfish Procambarus clarkii is present in most of the Portuguese rivers with well-known economic and environmental impacts, being also an important reservoir for many fungal and bacterial pathogens that can affect native aquatic fauna. Here the bacterial microbiota of the gut and carapace of the red swamp crayfish from three distinct localities in Portugal was characterized, using a metataxonomic approach. We tested whether biological measurements (sex, cephalotorax lenght, body condition and stress through glucose measurements) and sampling locality can be used as predictors of alpha and beta bacterial diversity. Results showed that the carapace microbiota are more responsive to differing environmental conditions than the gut microbiota, which are likely more affected by host factors, such as sex. Additionally, we have also found several potential pathogens in the microbiota of the analyzed crayfish. Our data provide a relevant baseline of the red swamp crayfish microbiota but highlight the need for further research, namely to fully characterize its role as a vector for bacterial diseases in freshwater ecosystems.