Exploring co-invasion dynamics: Parasitic interactions in the wake of Nile perch Invasion in Lake Victoria and its impact on the parasite fauna of haplochromine cichlids

Abstract

Biological invasions represent a significant threat to global biodiversity, impacting ecosystems and altering ecological dynamics. The introduction of the Nile perch (Lates niloticus) into Lake Victoria (East Africa), has led to ecological transformations, influencing the native fish communities. While much attention has been devoted to studying the ecological impacts of the Nile perch invasion on the native fish fauna and socio-economic consequences, little is known about the co-introduction dynamics of its potentially co-invasive parasites, as well as the impact on the gill macroparasite fauna of the native fishes impacted by the invasion (e.g. haplochromine cichlids). To investigate the co-introduction dynamics, we assessed the genetic and morphological diversity of Dolicirroplectanum lacustre, the only flatworm (Monogenea) parasite that infects lates perches across Africa. We found that D. lacustre was co-introduced with L. niloticus. In Lake Victoria, we found a reduction in the genetic and morphological diversity of D. lacustre compared with its native range, indicating a founder effect. To examine the broader ecological consequences of Nile perch invasion and human-induced eutrophication, we compared gill macroparasite communities of 13 native haplochromine cichlid species before and after these perturbations. We observed a reconfiguration of the host-parasite network that buffers the impacts of perturbations, indicating resilience. However, we observe a decrease in parasite-host range and infection parameters, highlighting the vulnerability of parasite communities to ongoing environmental changes associated with biological invasions. These findings underscore the importance of understanding the intricate dynamics of host-parasite interactions in the context of biological invasions and environmental change. By integrating insights from the invasive species dynamics and ecological perturbations, we provide valuable insights into the challenges and opportunities for conservation efforts to preserve ecosystem health and resilience in the face of global change.