Insights from Intralocus Tactical Conflict: Adaptive States, Interactions with Ecology and Population Divergence

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© 2019 The Authors. Oikos published by John Wiley & Sons on behalf of Nordic Society Oikos Alternative reproductive tactics (ARTs) have improved our understanding of the evolution of adaptive variation; for instance, their study has led us to understand that the best phenotype (e.g. large and flashy) for a tactic that uses one mating behavior (e.g. court females) is often not the best phenotype (e.g. small and inconspicuous) for a tactic that uses a different mating behavior (e.g. chase and force-copulate females). However, genetic correlations of shared traits across ARTs can constrain ARTs from reaching their optimal states, resulting in intralocus tactical conflict (IATC). While constraints on evolution in general have been well-established and studied, there are some important implications of constraints due to intralocus tactical conflict on ARTs that have not been incorporated into the field of evolutionary ecology. Here we describe how an appreciation of IATC, including how to detect it and when to expect it, can change our perspectives in three areas: 1) adaptive states for traits associated with ARTs (e.g. growth rates, behavioural plasticity); 2) how selection due to ecological variation across populations can produce patterns of divergence between ARTS; 3) and the evolutionary stability of polymorphisms (e.g. how IATC can explain losses of one ART, and why this can lead to rapid speciation).