The Role of Local Adaptation on Biting Performance in Trinidadian Guppies

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Organisms are faced with many challenges, including predation and resource availability, and these pressures can change across spatial gradients. For example, where predation pressures are low, an increase in population density will increase intraspecific competition for prey resources. However, how these changes in selective pressures lead to local adaptation, particularly in prey acquisition behaviors, needs further exploration. In Trinidadian guppies (Poecilia reticulata) a shift in selective pressure toward resource competition in low predation environments has resulted in local adaptation of many traits, including jaw morphology and diet. But whether these changes result in local adaptation of feeding performance remains unclear. Recent work in suction feeding of guppies has shown no difference between populations in feeding performance, suggesting an inability to adapt their feeding system. If selective pressures cause changes in resource use that drive adaptation for feeding, then low predation guppies should have increased biting kinematics compared to high predation guppies. To test this hypothesis we will film individuals from one low/high predation population pair with a high-speed camera while they feed on an agar substrate and measure feeding kinematics to test differences between populations. If gape, intramandibular joint mobility, and time of contact with the substrate are greater in low predation guppies, it would support the hypothesis that guppies are locally adapted to feeding conditions based on their habitat. Otherwise a lack of local adaptation could suggest either an inability to modify feeding performance or that the selection pressure on feeding is relatively weak.


Society for Integrative and Comparative Biology Annual Meeting (SICB)


Austin, TX