Influence of amino acid concentrations on foraging and feeding in the rusty crayfish Faxonius rusticus (Girard, 1852) (Decapoda: Astacidea: Cambaridae), assayed in flow-through mesocosms

Organisms use chemical cues in their environment to extract relevant information to perform a variety of tasks, including foraging, finding shelter, and locating mates, and must locate and assess the quality of food sources based on these chemical cues. Crayfishes use chemical cues in the form of amino acids to locate food and to regulate consumption when determining the quality of food sources. It is currently unknown, however, whether crayfish foraging and feeding behavior in experimental flow-through systems are altered by differing amino acid concentrations. We collected individuals of the rusty crayfish, Faxonius rusticus (), from two different watershed locations in Michigan, USA and exposed them to fish gelatin containing increasing concentrations of the amino acids beta-alanine (excitatory amino acid) and L-tyrosine (inhibitory amino acid). The gelatin was weighed before and after each 24-hour trial to determine consumption. The addition of an excitatory amino acid (beta-alanine) caused a significant drop in consumption but only for crayfish collected from one of the locations (P = 0.04). The addition of an inhibitory amino acid (L-tyrosine) had no effect on consumption from either location. This study demonstrates that feeding behaviors of F. rusticus are influenced by the presence of amino acids (beta-alanine) in food sources.