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Life Sciences

University of Massachusetts Amherst

Bite force

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Performance And Signaling In The Green Anole Lizard, Justin P. Henningsen Sep 2013

Performance And Signaling In The Green Anole Lizard, Justin P. Henningsen

Open Access Dissertations

Green anoles are small lizards of the Southeastern United States. They possess an extensible throat-fan called a dewlap. Males have larger dewlaps and display them more often than females. Displays occur during courtship, during agonistic interaction, and during encounters with potential predators. The size of the dewlap of male green anoles is positively correlated with maximum bite force capacity. Bite force capacity, in turn, is predictive of the winner during agonistic interactions. The correlation between these traits suggests that dewlap size may be used as a reliable signal of maximum bite force capacity. In this dissertation, I address three components …


Predicting Bite Force In Mammals: Two-Dimensional Versus Three-Dimensional Lever Models, Jl Davis, Se Santana, Er Dumont, Ir Grosse Jan 2010

Predicting Bite Force In Mammals: Two-Dimensional Versus Three-Dimensional Lever Models, Jl Davis, Se Santana, Er Dumont, Ir Grosse

Biology Department Faculty Publication Series

Bite force is a measure of whole-organism performance that is often used to investigate the relationships between performance, morphology and fitness. When in vivo measurements of bite force are unavailable, researchers often turn to lever models to predict bite forces. This study demonstrates that bite force predictions based on two-dimensional (2-D) lever models can be improved by including three-dimensional (3-D) geometry and realistic physiological cross-sectional areas derived from dissections. Widely used, the 2-D method does a reasonable job of predicting bite force. However, it does so by over predicting physiological cross-sectional areas for the masseter and pterygoid muscles and under …


Roost Making In Bats-Adaptations For Excavating Active Termite Nests, Dina K.N. Dechmann, Sharlene E. Santana, Elizabeth R. Dumont Jan 2009

Roost Making In Bats-Adaptations For Excavating Active Termite Nests, Dina K.N. Dechmann, Sharlene E. Santana, Elizabeth R. Dumont

Biology Department Faculty Publication Series

The breadth of an animals’ ecological niche is circumscribed by its morphology, performance, and behavior, 3 factors that can ultimately affect fitness. We investigated potential behavioral and performance adaptations to roost making, a life-history trait associated with high fitness in the insectivorous bat Lophostoma silvicolum. Males of this species use their teeth to excavate roosts in active termite nests, which we found to be much harder than the hardest prey in the bats’ diet (beetles). We compared roost making and feeding behavior in L. silvicolum. We also compared the feeding behavior of L. silvicolum to that of 2 …


Rapid Large-Scale Evolutionary Divergence In Morphology And Performance Associated With Exploitation Of A Different Dietary Resource, Anthony Herrel, Katleen Huyghe, Bieke Vanhooydonck, Thierry Backeljau, Karin Breugelmans, Irena Grbac, Raoul Van Damme, Duncan J. Irschick Jan 2008

Rapid Large-Scale Evolutionary Divergence In Morphology And Performance Associated With Exploitation Of A Different Dietary Resource, Anthony Herrel, Katleen Huyghe, Bieke Vanhooydonck, Thierry Backeljau, Karin Breugelmans, Irena Grbac, Raoul Van Damme, Duncan J. Irschick

Biology Department Faculty Publication Series

Although rapid adaptive changes in morphology on ecological time scales are now well documented in natural populations, the effects of such changes on whole-organism performance capacity and the consequences on ecological dynamics at the population level are often unclear. Here we show how lizards have rapidly evolved differences in head morphology, bite strength, and digestive tract structure after experimental introduction into a novel environment. Despite the short time scale (≈36 years) since this introduction, these changes in morphology and performance parallel those typically documented among species and even families of lizards in both the type and extent of their specialization. …


The Effects Of Gape Angle And Bite Point On Bite Force In Bats, Elizabeth R. Dumont, Anthony Herrel Jan 2003

The Effects Of Gape Angle And Bite Point On Bite Force In Bats, Elizabeth R. Dumont, Anthony Herrel

Biology Department Faculty Publication Series

Models of mammalian mastication predict that bite force is affected by both the degree of mouth opening (gape angle) and the point along the tooth row at which force is transferred to a food item (bite point). Despite the widespread use of these models in comparative analyses, experimental data documenting bite force in non-human mammals are extremely limited. The goal of this study is to document variation in non-stimulated bite force associated with change in gape angle and bite point in a broad range of species. We focus on plant-visiting bats because they exhibit a relatively primitive cranial morphology and …