Sensing with the legs: contribution of pereiopods in the detection of food-related compounds in the red swamp crayfish Procambarus clarkii

The red swamp crayfish Procambarus clarkii (Girard, 1852) is one of the most hazardous invasive alien species of freshwater habitats. Like other decapod crustaceans, crayfish rely on chemical senses to detect and localize food resources. By way of extracellular nerve recordings coupled with behavioural bioassays, we investigated the sensitivity spectra of the walking leg chemoreceptors of P. clarkii in response to different food-related compounds. Recordings from isolated legs confirmed a marked sensitivity of the legs to trehalose, cellobiose, sucrose, maltose, glycine, and leucine. Some sensitivity to glucose, fructose, asparagine, and taurocholic acid was also found. Under confined experimental conditions, the behavioural bioassays excluded involvement of antennules in the detection of food-related compounds, thus emphasizing the role of the legs as the main short-distance, broad-spectrum sensors involved in feeding. Such information could be valuable for the identification of key chemicals aimed at the future development of strategies for crayfish population control programs.