Contamination may induce behavioural plasticity in the habitat selection by shrimps: A cost-benefits balance involving contamination, shelter and predation

When shrimps select a habitat, the presence of elements like predators, shelter and contamination might determine if an area is preferred or avoided. We hypothesised that when shrimps are exposed to a situation in which they have to select whether to avoid contamination, seek shelter or protect themselves against predators, they will avoid the situation that supposes a higher cost for their survival (cost-benefits balance). The current study aimed to assess the plasticity of the selection behaviour of the freshwater shrimp Atyaephyra desmarestii between moving to a clean and unprotected area (no shelter and with a risk of predation), thus avoiding exposure to contamination, or moving to a contaminated and protected area (with shelters), thereby avoiding potential predators. Shrimps were experimentally exposed in a free-choice system simulating a heterogeneous environment with a contaminant (copper), shelter and a predator signal (kairomones of Salmo trutta). The shrimps avoided the copper by moving towards a less contaminated area, both in the absence or presence of shelter. When confronted with a choice between a cleaner zone with no shelter and a contaminated zone with shelter, the shrimps preferred being in the cleanest area. However, when the uncontaminated area contained a predator signal, the shrimps balanced the risk of predation and exposure to contamination by selecting a moderately contaminated area relatively further away from the predator signals. In summary, contamination might favour a plasticity of the habitat selection behaviour of shrimps, modifying the cost-benefits balance of such a selection.

C.V.M. Araújo received the Ramón y Cajal contract (RYC-2017-22324) from Spanish Ministry of Science and Innovation. K.C. Pereira received a doctoral fellowship (2014-0693/001-EMJD) from the Erasmus Mundus Programme (PhD in Marine and Coastal Management). The authors are grateful to D. Roque and A. Moreno (technical help in the fieldwork), M.C. Agullo (laboratory assistance), María del Valle Peláez from the fishfarm Piscifactoría Andaluzas - Genazar (help with the trout culture) and J. Nesbit (assistance with the revision of the English text). This study was funded by the Spanish Ministry of Science and Innovation (Explora Project: #CGL2017-92160-EXP and i-COOP2019 program from CSIC: COOPB20444).

Peer reviewed