RT Journal Article SR Electronic T1 A taste for numbers: Caenorhabditis elegans foraging follows a low-dimensional rule of thumb JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.06.21.496406 DO 10.1101/2022.06.21.496406 A1 Gabriel Madirolas A1 Alid Al-Asmar A1 Lydia Gaouar A1 Leslie Marie-Louise A1 Andrea Garza-Enriquez A1 Mikail Khona A1 Christoph Ratzke A1 Jeff Gore A1 Alfonso Pérez-Escudero YR 2022 UL http://biorxiv.org/content/early/2022/06/23/2022.06.21.496406.abstract AB Rules of thumb are behavioral algorithms that approximate optimal behavior while lowering cognitive and sensory costs. One way to reduce these costs is by reducing dimensionality: While the theoretically optimal behavior may depend on many environmental variables, a rule of thumb may use a low-dimensional combination of variables that performs reasonably well. Experimental proof of a dimensionality reduction requires an exhaustive mapping of all relevant combinations of several environmental parameters, which we performed for Caenorhabditis elegans foraging by covering all combinations of food density (across 4 orders of magnitude) and food type (across 12 bacterial strains). We found a one-dimensional rule: Worms respond to food density measured as number of bacteria per unit surface, disregarding other factors such as biomass content or bacterial strain. We also measured fitness experimentally, determining that the rule is near-optimal and therefore constitutes a rule of thumb that leverages the most informative environmental variable.Competing Interest StatementThe authors have declared no competing interest.