HR: 1330h
AN: NB33P-08    [Abstracts]
TI: Use of Biomechanical Analyses of Cranial Variation to Interpret Feeding Components of the Niche in Larval Dytiscid Beetles (Coleoptera: Dytiscidae)
AU: * Barman, E
EM: e.barman@gcsu.edu
AF: Georgia College & State University, Dept. of Biological & Environmental Sciences, Milledgeville, GA 31061 United States
AU: Wall, W P
EM: bill.wall@gcsu.edu
AF: Georgia College & State University, Dept. of Biological & Environmental Sciences, Milledgeville, GA 31061 United States
AU: Shepley, T
EM: tiffany.shepley@bobcat.gcsu.edu
AF: Georgia College & State University, Dept. of Biological & Environmental Sciences, Milledgeville, GA 31061 United States
AB: Dytiscid larvae are obligatory predators with most using extra-oral digestion to feed on aquatic invertebrates and small vertebrates. Three aspects of cranial morphology are presented here to illustrate the strong selective force feeding success has on cranial morphology. First, distortion gird analysis of ontogenetic allometry revealed significant changes in Agabus disintegratus during larval development. These differences are most likely the result of ontogenetic shifts in prey preferences in A. disintegratus leading to anisomorphic increases in mandibular musculature during development. Second, evolutionary allometry of lateral head shape in larvae of Matus bicarinatus, Coptotomus lenticus, and Thermonectus basilaris revealed prognathic, hypoprognathic and hyperprognathic patterns of orientation. This variation in cranial architecture may be an indicator of differences in prey regimes exploited by each taxon. And third, geometric analysis of mandibular shape to predict the food habits of Acilius mediatus, Agabus punctatus, and Rhantus calidus revealed significant differences in camber, arc, and angle of attack. These data indicate that mandibular geometry may be strongly influenced by prey choice. Biomechanical methods could have predictive value for identifying larval food habits. This project was supported by a Faculty Research Grant, Office of Research Services, GC&SU. Aquatic Coleoptera Laboratory Contribution No. 61
DE: 0399 General or miscellaneous
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly