Technical note: Converting durometer data into elastic modulus in biological materials

Pampush, James D.; Daegling, David J.; Vick, Anna E.; McGraw, W. Scott; Covey, Ryan M.; Rapoff, Andrew J.

doi:10.1002/ajpa.21628

Cited by 17 publications

(12 citation statements)

References 13 publications

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“…In the context of fallback adaptations, this is significant because Sacoglottis seeds are also the hardest, most mechanically challenging foods in the sooty mangabey diet. Material testing of this food in the field and the laboratory indicate that seed hardness values are greater than those of cherry pits and popcorn kernels Pampush et al, 2011). Despite its mechanical properties, sooty mangabey of both sexes and all (postweaning) ages routinely consume Sacoglottis seeds by employing a powerful isometric bite on the postcanine tooth row to breach the seed's outer casing McGraw et al, 2011).…”

Section: Discussionmentioning

confidence: 98%

Dietary variation and food hardness in sooty mangabeys (Cercocebus atys): Implications for fallback foods and dental adaptation

McGraw

Vick

Daegling

2014

American J Phys Anthropol

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We present information on food hardness and monthly dietary changes in female sooty mangabeys (Cercocebus atys) in Tai Forest, Ivory Coast to reassess the hypothesis that thick molar enamel is parsimoniously interpreted as a response to consumption of hard foods during fallback periods. We demonstrate that the diet of sooty mangabeys varies seasonally, but that one food--Sacoglottis gabonensis--is the most frequently consumed food every month and year round. This food is the hardest item in the sooty diet. Given that this species has among the thickest enamel within the primate order, a plausible conclusion is that thick enamel in this taxon evolved not in response to seasonally critical function or fallback foods, but rather to the habitual, year round processing of a mechanically protected foodstuff. These data serve as a caution against de rigueur interpretations that reliance on fallback foods during lean periods primarily explains the evolution of thick enamel in primates.

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Section: Discussionmentioning

confidence: 98%

Dietary variation and food hardness in sooty mangabeys (Cercocebus atys): Implications for fallback foods and dental adaptation

McGraw

Vick

Daegling

2014

American J Phys Anthropol

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“…For each mericarp, we measured hardness (0–100 value on a Shore D scale; Pampush et al. ) using a handheld durometer (Asker, Super Ex, Type D, Kyoto, Japan). As the structure of the mericarp wall varies over its surface (Fig.…”

Section: Methodsmentioning

confidence: 99%

The ecology and evolution of seed predation by Darwin's finches on Tribulus cistoides on the Galápagos Islands

Carvajal‐Endara

Hendry

Emery

et al. 2019

Ecological Monographs

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Predator-prey interactions play a key role in the evolution of species traits through antagonistic coevolutionary arms races. The evolution of beak morphology in the Darwin's finches in response to competition for seed resources is a classic example of evolution by natural selection. The seeds of Tribulus cistoides are an important food source for the largest ground finch species (Geospiza fortis, G. magnirostris, and G. conirostris) in dry months, and the hard spiny morphology of the fruits is a potent agent of selection that drives contemporary evolutionary change in finch beak morphology. Although the effects of these interactions on finches are well known, how seed predation affects the ecology and evolution of the plants is poorly understood. Here we examine whether seed predation by Darwin's finches affects the ecology and evolution of T. cistoides. We ask whether the intensity of seed predation and the strength of natural selection by finches on fruit defense traits vary among populations, islands, years, or with varying finch community composition (i.e., the presence/absence of the largest beaked species, which feed on T. cistoides most easily). We then further test whether T. cistoides fruit defenses have diverged among islands in response to spatial variation in finch communities. We addressed these questions by examining seed predation by finches in 30 populations of T. cistoides over 3 yr. Our study reveals three key results. First, Darwin's finches strongly influence T. cistoides seed survival, whereby seed predation varies with differences in finch community composition among islands and in response to interannual fluctuations in precipitation. Second, finches impose phenotypic selection on T. cistoides fruit morphology, whereby smaller and harder fruits with longer or more spines exhibited higher seed survival. Variation in finch community composition and precipitation also explains variation in phenotypic selection on fruit defense traits. Third, variation in the number of spines on fruits among islands is consistent with divergent phenotypic selection imposed by variation in finch community composition among islands. These results suggest that Darwin's finches and T. cistoides are experiencing an ongoing coevolutionary arms race, and that the strength of this coevolution varies in space and time.

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“…Mangabeys ( Cercocebus and Lophocebus ) are dedicated seed predators (Brugiere et al, ; McGraw, Vick, & Daegling, ; Wieczkowski, ). The red‐capped mangabey Cercocebus torquatus grinds hard and brittle seeds (Pampush et al, ). In addition, it is known to crack the hard and tough seed shells of Sacoglottis gabonensis (Daegling et al, ; McGraw et al, , ).…”

Section: Action‐related Categories: Using Food Mechanical Properties mentioning

confidence: 99%

Investigating the dental toolkit of primates based on food mechanical properties: Feeding action does matter

Thiery

Guy

Lazzari

2017

American J Primatol

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Although conveying an indisputable morphological and behavioral signal, traditional dietary categories such as frugivorous or folivorous tend to group a wide range of food mechanical properties together. Because food/tooth interactions are mostly mechanical, it seems relevant to investigate the dental morphology of primates based on mechanical categories. However, existing mechanical categories classify food by its properties but cannot be used as factors to classify primate dietary habits. This comes from the fact that one primate species might be adapted to a wide range of food mechanical properties. To tackle this issue, what follows is an original framework based on action-related categories. The proposal here is to classify extant primates based on the range of food mechanical properties they can process through one given action. The resulting categories can be used as factors to investigate the dental tools available to primates. Furthermore, cracking, grinding, and shearing categories assigned depending on the hardness and the toughness of food are shown to be supported by morphological data (3D relative enamel thickness) and topographic data (relief index, occlusal complexity, and Dirichlet normal energy). Inferring food mechanical properties from dental morphology is especially relevant for the study of extinct primates, which are mainly documented by dental remains. Hence, we use action-related categories to investigate the molar morphology of an extinct colobine monkey Mesopithecus pentelicus from the Miocene of Pikermi, Greece. Action-related categories show contrasting results compared with classical categories and give us new insights into the dietary adaptations of this extinct primate. Finally, we provide some possible directions for future research aiming to test action-related categories. In particular, we suggest acquiring more data on mechanically challenging fallback foods and advocate the use of other food mechanical properties such as abrasiveness. The development of new action-related dental metrics is also crucial for primate dental studies.

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Technical note: Converting durometer data into elastic modulus in biological materials

Cited by 17 publications

References 13 publications

Dietary variation and food hardness in sooty mangabeys (Cercocebus atys): Implications for fallback foods and dental adaptation

Dietary variation and food hardness in sooty mangabeys (Cercocebus atys): Implications for fallback foods and dental adaptation

The ecology and evolution of seed predation by Darwin's finches on Tribulus cistoides on the Galápagos Islands

Investigating the dental toolkit of primates based on food mechanical properties: Feeding action does matter

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