Abstract
Pomacea canaliculata is an invasive species which has significantly impacted native ecosystems globally. The benthic worm Limnodrilus hoffmeisteri is essential for the stability of the native aquatic ecosystem, facilitating the nutrient cycle dynamics through bioturbation. Nevertheless, limited information exists regarding the impact of P. canaliculata on those key native benthic species. Present study evaluated the impacts of P. canaliculata on L. hoffmeisteri by exposing L. hoffmeisteri to P. canaliculata (PC group) and the native snail Bellamya aeruginosa (BA group), with a control group consisting of no snails (NS group). The survival rate of L. hoffmeisteri in the PC group persisted diminished over 14 days, with notable declines in the rates of successful food acquisition and aggregation, an increase in migration, and a decrease in swing frequency. Elevated oxidative stress levels were linked to these alterations in L. hoffmeisteri behavior. Additionally, the presence of P. canaliculata increased the abundance of intestinal pathogenic bacteria in L. hoffmeisteri, with Aeromonas being one of the most lethal. Experimental models of Aeromonas-free P. canaliculata (AFPC), re-infected AFPC (IPC), and Aeromonas (As) were established to illustrate the role of Aeromonas in the decline of L. hoffmeisteri. Similar patterns in L. hoffmeisteri survival, behavior, and oxidative stress were observed in As, IPC, and PC group; however, these effects were mitigated by the elimination of Aeromonas in the AFPC group. Furthermore, L. hoffmeisteri was fatally affected by the four Aeromonas strains that were obtained from P. canaliculata intestine. These findings indicate that P. canaliculata exerts a deleterious impact on L. hoffmeisteri, and Aeromonas colonizing in intestine plays an important role. This study reveals a novel invasion mechanism of P. canaliculata.