Meeting Abstract
Animal contests occur over indivisible resources. On average, winners have higher resource holding potential (RHP), which is a composite measure encompassing variables like size, physiological state, and skill. During mutual assessment, animals estimate the relative RHP of their opponent to decide when to leave contests. However, the cognitive mechanisms underlying mutual assessment are unknown. One possibility is that animals indirectly assess RHP by assessing a correlated but more accessible attribute – the heuristic attribute. Using a heuristic allows animals to make fast decisions with readily available information. Here, we show that snapping shrimp conduct mutual assessment using a heuristic based on recent contest success. In snapping shrimp, recent contest winners signify recent success through a chemical signal. We hypothesized that snapping shrimp use this signal as a heuristic attribute for RHP. To test our hypothesis, we collected 52 snapping shrimp from Beaufort, SC. We tested predictions made by different assessment types by staging 26 randomly matched contests and 24 RHP-matched contests. Then, we tested if snapping shrimp use a heuristic based on recent contest success by staging an additional 24 contests between individuals with recent contest experience – 12 between small recent winners and large recent losers and 12 between large recent winners and small recent losers. We found that snapping shrimp settle contests using mutual assessment and a heuristic based on recent contest success. This minimizes the energetic costs and risk of injury associated with gathering reliable information. Similar heuristic-based decision rules might be widespread across animals and behaviors because they facilitate quick decisions while minimizing costs.
