Convergent feeding kinematics in elongate cichlids

Meeting Abstract

P2.56  Saturday, Jan. 5  Convergent feeding kinematics in elongate cichlids CHOW, JS*; BERG, CL; HYMES, M; MCGEE, MD; WAINWRIGHT, PC; University of California, Davis; University of California, Davis; University of California, Davis; University of California, Davis; University of California, Davis

Feeding behaviors are often expected to diverge between phylogenetically distant and ecologically dissimilar species. We tested this assumption by examining the feeding behavior of Crenicichla strigata and Rhamphochromis longiceps, two distantly related cichlid species. Crenichla strigata is a benthic ambush predator from the Amazon River, while Rhamphochromis longiceps is a pelagic pursuit predator from Lake Malawi. The two species have independently evolved elongate heads with large jaws from morphologically and kinematically generalized species. We tested for the presence of convergent feeding kinematics by analyzing videos recorded using a Fastec Hispec 1 camera at 2000 frames per second to film three C. strigata and three R. longiceps capturing small cyprinid prey. Video sequences were digitized using a custom modification of the Dltdv3 package in MATLAB. We tracked eleven points on the head, body, prey item, and background through the duration of the strike. Then we generated six excursion variables and six time to peak movement variables for gape, hyoid depression, jaw protrusion, strike distance, lower jaw rotation, head elevation, and capture of the prey item. To analyze kinematics, we used mixed models with species and size as fixed effects, and individual as a random effect. We found no significant differences in the excursions and timings of C. strigata and R. longiceps, except for a marginally significant larger maximum gape in R. longiceps. This suggests that Crenicichla strigata and Rhamphochromis longiceps have evolved convergent feeding strikes despite clear differences in their evolutionary history, habitat, and predation strategies. Our results indicate that convergence in feeding behavior can occur between phylogenetically and ecologically divergent species.

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