Animal dispersal costs are not universal

This is a Preprint and has not been peer reviewed. This is version 2 of this Preprint. You must log in to post a comment. There are no comments or no comments have been made public for this article. This is a Preprint and has not been peer reviewed. This is version 2 of this Preprint. Add a Comment You must log in to post a comment. Comments There are no comments or no comments have been made public for this article. Dispersal is a keystone process shaping ecological and evolutionary dynamics, often assumed to be inherently costly. We synthesized 717 effect sizes from 210 studies across 150 animal species, spanning all continents and ecosystems, to test this assumption. Contrary to long-standing dogma, we found no overall effect of dispersal on fitness (mean effect size: -0.02, 95% CIs: -0.08 to 0.03). No tested biological or methodological moderators explained this variation. Instead, heterogeneity was highest within studies, suggesting that dispersal is highly context-dependent within studies and species. These findings align with game-theoretic expectations that dispersal and philopatry are alternative strategies maintained by balancing or frequency-dependent selection. Our findings are consistent with the view that dispersal involves a balancing act between strategies that yield equivalent long-term payoffs across variable conditions. https://doi.org/10.32942/X2PQ02 Ecology and Evolutionary Biology, Life Sciences dispersal, costs, benefits, fitness, movement, animals, natal dispersal, breeding dispersal, migration Published: 2025-10-27 21:34 Last Updated: 2026-03-04 16:09 CC BY Attribution 4.0 International Data and Code Availability Statement: https://github.com/martinig/Fitness-and-dispersal-MA Language: English