| Title: | Irrational risk aversion in an ant |
| Author(s): | De Agro M; Grimwade D; Bach R; Czaczkes TJ; |
| Address: | "Department of General Psychology, University of Padova, Padova, Italy. massimo.de-agro@ur.de. Animal Comparative Economics Laboratory, Department of Zoology and Evolutionary Biology, University of Regensburg, Regensburg, Germany. massimo.de-agro@ur.de. John Harvard Distinguished Science Fellows Program, Harvard University, Cambridge (MA), USA. massimo.de-agro@ur.de. Department of Organismic and Evolutionary Biology, Harvard University, Cambridge (MA), USA. massimo.de-agro@ur.de. Animal Comparative Economics Laboratory, Department of Zoology and Evolutionary Biology, University of Regensburg, Regensburg, Germany. Department of Zoology, University of Oxford, Oxford, UK" |
| DOI: | 10.1007/s10071-021-01516-1 |
| ISSN/ISBN: | 1435-9456 (Electronic) 1435-9448 (Print) 1435-9448 (Linking) |
| Abstract: | "Animals must often decide between exploiting safe options or risky options with a chance for large gains. Both proximate theories based on perceptual mechanisms, and evolutionary ones based on fitness benefits, have been proposed to explain decisions under risk. Eusocial insects represent a special case of risk sensitivity, as they must often make collective decisions based on resource evaluations from many individuals. Previously, colonies of the ant Lasius niger were found to be risk-neutral, but the risk preference of individual foragers was unknown. Here, we tested individual L. niger in a risk sensitivity paradigm. Ants were trained to associate one scent with 0.55 M sucrose solution and another with an equal chance of either 0.1 or 1.0 M sucrose. Preference was tested in a Y-maze. Ants were extremely risk-averse, with 91% choosing the safe option. Based on the psychophysical Weber-Fechner law, we predicted that ants evaluate resources depending on their logarithmic difference. To test this hypothesis, we designed 4 more experiments by varying the relative differences between the alternatives, making the risky option less, equally or more valuable than the safe one. Our results support the logarithmic origin of risk aversion in ants, and demonstrate that the behaviour of individual foragers can be a very poor predictor of colony-level behaviour" |
| Keywords: | Animals *Ants Pheromones Ants Psychophysics Risk aversion Utility Value perception; |
| Notes: | "MedlineDe Agro, Massimo Grimwade, Daniel Bach, Richard Czaczkes, Tomer J eng CZ 237/1-1/Deutsche Forschungsgemeinschaft/ Germany 2021/05/04 Anim Cogn. 2021 Nov; 24(6):1237-1245. doi: 10.1007/s10071-021-01516-1. Epub 2021 May 3" |
