Asynchronous life histories generate uneven arms races and impact the maintenance of mutualisms

Mutualisms constitute a diverse class of ecologically important interactions, yet their ecological and evolutionary stability remain topics of debate in coevolutionary theory. Recent theoretical and empirical work has suggested that coevolutionary arms races may be involved in the maintenance of mutualistic interactions, sustaining mutually beneficial outcomes for interacting species while producing exaggerated traits. Here we present an individual-based model that evaluates how asynchronous life histories – i.e., partners with different average lifespans – change the dynamics of trait coevolution, the expected fitness outcomes for species involved, and the dynamics of selection differentials across time for each species. Results indicate that a longer-lived mutualist will consistently ‘lose’ an otherwise balanced coevolutionary arms race, being outpaced in both the mean trait value and fitness outcome compared to a shorter-lived partner. Furthermore, linear selection differentials on m..., This data was simulated using the included scripts. All processing is done by the scripts themselves. A README.md file is included to describe how the data and scripts should be used., , # Asynchronous life histories generate uneven arms races and impact the maintenance of mutualisms

Authors: Aaron Westmoreland & Nancy Emery

Summary: This study evaluates how asyncrhonous life histories affect the pace and outcomes of mutualistic coevolutionary arms races. In particular, it looks at how disparities in longevity and generation time (i.e., when one species is longer lived than its partner and thus generations do not align cleanly) affects the rates of evolutionary change in each species, the benefits each species gains from the interactions, and
the behavior of the selection differential in each species. We find that as the disparity between life histories is increased, arms races become increasingly uneven with the longer-lived species experiencing stronger selection while gaining decreased benefits compared to its partner. We discuss these results in the context of the long-term maintenance of mutualistic interactions, the Red Queen vs Red King Hypotheses for mutua...