FERRY-GRAHAM, LA; GIBB, AC; California State Univ./Moss Landing Marine Labs; Northern Arizona Univ.: The teleost suction-feeding mechanism: How is it modified for specialized foraging behaviors?
Ballistic expansion of the head is used by most aquatic predators to produce suction during prey capture. In this study, we seek to determine if the teleost fishes show variable patterns of cranial movements during the expansive phase of a suction-feeding event. We quantified cranial kinematics from fourteen species and compared them using a multi-dimensional analysis. We asked two questions: (1) is there a stereotypical suction-feeding pattern among diverse taxa, and (2) do species hypothesized to be suction specialists demonstrate similar modifications to this pattern? We used ten kinematic variables in a Principle Components Analysis (PCA) to identify axes of variation among species. MANOVA and Tukey post-hoc tests with the significant axes as dependent variables were used to determine which species differed from one another. Plots of the PCA scores revealed that most species clustered near the origin on all axes. This pattern likely represents a stereotypical suction feeding mechanism, conserved across many teleost groups including the phyologenetically primitive Cypriniformes. Typically, only one species stood out as “extreme” on each axis. This species was different on each axis suggesting that different movements were produced by each extreme species. Only one species demonstrated modifications to prey capture kinematics consistent with enhanced suction production. Instead, we observed that predators modified variables in a manner consistent with other modes of prey capture such as ram or biting. For some species, changes necessary to enhance suction production may result in reduced performance in other feeding modes. Due to the density and viscosity of the aquatic medium, it may also be difficult to improve upon suction production without major modifications to the neurocranium. Lastly, it may be that highly elusive prey are required to trigger extreme suction feeding in some species.
