Behaviour 2019
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The effects of novelty on aggression, feeding kinematics, and mate choice within a radiation of pupfishes
Michelle St. John, Chris Martin. University of California , Berkeley, CA, United States

Shifts in behavior, morphology, and kinematic traits have all been suggested as mechanisms for producing novelty. However, it is unclear how adaptive changes for novelty may affect the formation of reproductive isolation. Here, we investigate this relationship using snail- and scale-eating within a recent radiation of Cyprinodon pupfishes endemic to San Salvador Island, Bahamas.  We used behavioral assays and kinematic data to investigate how shifts in adaptive traits lead to the formation of reproductive isolation. First, we found increased behavioral aggression in both snail-eating and scale-eating specialists, indicating that aggression may be adaptive for specialization. Second, we found that scale-eating pupfish use a unique jaw angle when scale-feeding, and that this may be a source of extrinsic reproductive isolation between species. Finally, we measured conspecific mate preferences and found that generalist and snail-eating pupfish had strong preferences against mating with scale-eaters. Ultimately, we found evidence for the cascading effects of novelty on reproductive isolations via shifts in aggression and feeding kinematics.