Effects of temperature and a manipulative parasite on the swimming behaviour of Gammarus pulex in flowing water

Numerous freshwater acanthocephalans are able to alter the behaviour of their intermediate hosts to increase their predation risk by final hosts, thereby enhancing trophic transmission between their two hosts. Because temperature is widely expected to impact freshwater host-parasite interactions, we investigated how it can affect movements of both uninfected and Pomphorhynchus laevis-infected Gammarus pulex in an artificial stream in 5 cm/s water flow. We found that P. laevis infection of G. pulex induced both higher frequency and higher amplitude of movements along the artificial stream. Moreover, at warmer temperature (21 degrees C), uninfected and P. laevis-infected G. pulex moved more in the artificial stream than at 15 degrees C. In this regard, warmer temperature could then impact gammarids distribution and increase P. laevis transmission rate toward their definitive host in freshwater ecosystems. Firstly, this study provides new insights into how the key temperature factor influences gammarids species movements in the stream. Secondly, elevated temperature did not influence the intensity of P. laevis manipulation in G. pulex intermediate host. This work highlights that warmer temperature might affect the distribution and the behaviour of infected or uninfected freshwater gammarids with no direct effect on acanthocephalan trophic transmission through manipulation.

Automated summary

This study provides insights into how temperature influences movements of gammarid species in the stream. Elevated temperature did not affect the intensity of P. laevis manipulation in G. pulex as intermediate host.