The sensory drive hypothesis is a hypothesis in population ecology that posits that when local environmental conditions differ between conspecific populations, communication systems will adapt to these conditions. Sensory drive predicts that both communication signals and perceptual systems will adapt to these local environmental conditions. Divergence will then occur based on the intensity and direction of selection on the mating signals and on the sensory systems acquiring information regarding predators, prey, and potential mates. The sensory drive hypothesis has two primary assumptions. The first is that greater sensory stimulation results in preferences for mates with the stimulating trait, meaning exaggerated traits are expected to have greater signal value and generate more mating because they cause a stronger response from the sensory system. In this sense, it is possible for sensory drive to contribute to the formation of runaway traits when sexual selection is working in the same direction as the sensory biases. The second assumption is that biases are relatively fixed and show limited developmental plasticity. Mating signals, perceptual systems, and behavioral responses are not independent. As a result, as one of these diverges based on selective pressures, the others should also diverge unless under independent selection against divergence. While sensory drive is likely not the primary driver involved in speciation, it is able to set the initial evolutionary trajectory of an aspect involved in these communication signals that can be acted on by evolutionary forces to drive speciation. To find support for the sensory drive hypothesis, there needs to be a match between the biases of the sensory system predicted by environmental constraints and a match between signals and that sensory bias. As of 2018, support has been found for the sensory component with there being a strong bias towards aquatic systems (57% of studies) and visual signals (83% of studies). There is also support for the signal component with more bias towards terrestrial systems (71% of studies) and visual signals (57% of studies). There have also been papers focused on identifying support for both the sensory and signal components; of these papers, only those with support for the sensory drive hypothesis have been published. Similar to the studies focusing on the sensory component, there is a bias towards aquatic systems (62% of studies) and visual signals (86% of studies) with the majority of these being focused on fish taxa (55% of studies).
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