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Dissertation/Thesis Abstract

The Mechanisms of a Successful Intraguild Predator
by Penning, David A., Ph.D., University of Louisiana at Lafayette, 2016, 126; 10243639
Abstract (Summary)

The objective of this research was to quantify and better understand the mechanisms of performance in constricting snakes. Many non-venomous snakes use constriction to subdue and kill different types, sizes, and quantities of prey. Using eastern kingsnakes (Lampropeltis getula), I measured the effects of prey size and repeated feeding on constriction performance. I found that prey size alone did not affect constriction performance, but when kingsnakes encountered additional prey of medium and large sizes, they experienced significant reductions in the length of the body used and peak constriction pressure. In addition to feeding on a variety of different mammalian prey, kingsnakes (Lampropeltis spp.) are known to feed on other snakes, including other constrictors (Pantherophis ssp.). To begin addressing how this is possible, I studied the scaling of muscle cross-sectional area, pulling force as an indicator of escape performance, and constriction pressure as a measure of predation performance across the ontogeny of six species of snakes (three kingsnake and three ratsnake species). Muscle cross-sectional area and pulling force scaled similarly for all snakes, but all kingsnakes were able to exert significantly higher peak constriction pressures on their prey than ratsnakes. The ability to exert higher pressures suggests that kingsnakes may have differences in muscle anatomy and physiology that have gone untested. In another experiment, I described and quantified nine different muscles in speckled kingsnakes (L. holbrooki) and western ratsnakes (P. obsoletus) in order to better compare their anatomy. There were no significant differences in quantitative measures of musculature between these two species. Finally, I compared individual muscle performance between kingsnakes and ratsnakes by testing in vivo muscle force production and endurance. There was no difference between muscle force and endurance in our sample of kingsnakes and ratsnakes. The results from all chapters together indicate that kingsnakes are able to produce significantly higher constriction pressures because of their consistent coil posture (behavior) and not because of differences in their muscle anatomy or physiology. Integrated studies of behavior and its underlying mechanisms, such as in these chapters, are critical to making strong inferences about relationships in predator–prey interactions and their outcomes.

Indexing (document details)
Advisor: Moon, Brad
Commitee: Albert, James, Herrel, Anthony, Leberg, Paul, Povinelli, Daniel
School: University of Louisiana at Lafayette
Department: Biology
School Location: United States -- Louisiana
Source: DAI-B 78/12(E), Dissertation Abstracts International
Subjects: Biology, Biomechanics, Physiology
Keywords: Colubrid, Constriction, Muscle, Predation, Scaling, Snake
Publication Number: 10243639
ISBN: 978-0-355-11287-0
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