The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Biting off more than you can chew: a regional assessment of diet-induced plasticity

ERIN M. FRANKS1, JOSEPH P. SCOLLAN1, FAISAL S. SHARIFF1, JEREMIAH E. SCOTT4, KEVIN R. MCABEE1 and MATTHEW J. RAVOSA1,2,3.

1Department of Biological Sciences, University of Notre Dame, 2Department of Aerospace and Mechanical Engineering, University of Notre Dame, 3Department of Anthropology, University of Notre Dame, 4Department of Anthropology, Southern Illinois University

March 27, 2015 8:45, Grand Ballroom A/B Add to calendar

The effect of dietary properties on craniofacial form has long been the focus of functional and paleontological studies, with extensive work dedicated to the importance of phenotypic plasticity. However, the role of temporal dietary variability has received less attention, specifically the morphological correlates of fallback foods, which are lower quality, difficult-to-process items consumed due to seasonal dietary resources. How such dietary variability affects plasticity in non-masticatory regions, such as the neurocranium, is also poorly understood. Accordingly, there is a significant gap in our understanding of dietary seasonality on patterns of cranial covariation and integration.

Thirty weanling Oryctolagus cuniculus were divided equally among three dietary cohorts and raised until one year old. Control rabbits were fed pellets only. Seasonal rabbits were fed pellets and hay cubes for the beginning of the experiment followed by a shift to an all-pellet diet, simulating seasonal reliance on fallback foods. This schedule was then repeated. Annual rabbits were given pellets and hay cubes for the duration, modeling a mechanically challenging diet. MicroCT was conducted biweekly to detail linear and angular changes in calvarial and basicranial development. Results indicate that diet-induced differences in mechanical loading do not influence phenotypic plasticity in the neurocranium, a notable contrast to marked osteogenic responses observed in masticatory elements. This disparity suggests that long-term loading imparts an effect on cranial locations more directly involved in feeding behaviors. It also highlights functional and developmental variation in determinants of morphological integration in the skull, information of utility for ecomorphological, paleobiological, and evolutionary research.

Funding for this research was provided by National Science Foundation grant BCS-1029149/1214767 to MJR.