Spatial dynamics in the social lobster Panulirus argus in response to diseased conspecifics

Pathogens can influence the behaviors of their hosts, including avoidance by healthy individuals. However, the spatial structuring consequences of these behaviors are often unknown, especially in the marine environment. The Caribbean spiny lobster Panulirus argus (Latreille, 1804) avoids sheltering with conspecifics infected with P. argus virus 1 (PaV1). We sought to determine the behavioral cue and if this behavior alters population spatial structure in the wild. We used a series of laboratory Y-maze experiments to determine the mechanism of detection and also employed artificial shelter arrays placed in different flow conditions in the field to determine the effect of diseased lobster aversion on healthy lobster spatial dynamics. Results showed that avoidance is driven by the chemoreception of cues based in the urine. The chemical cue alone was as effective as having a diseased lobster present and visible. The presence of single PaV1-infected lobsters altered the small-scale spatial structure of wild populations, especially under low flow regimes, via redistribution of neighboring individuals. In shelter-limited environments, disease avoidance has the potential to increase juvenile mortality, as nearby conspecifics are displaced from dens and exposed to a higher risk of predation.