The effect of tooth shape on the breakdown of insects

Abstract

This study investigates the effect of tooth sharpness on the force and energy necessary for a tooth to divide foods of differing physical properties. The material properties of foods are likely to affect the shape that is best to divide them. In order to test the effect of sharpness on a tooth's pro®ciency in dividing insect prey, experiments involving penetrating and driving through insect prey of differing physical properties were carried out using specially designed punches that varied in tip-and cusp-sharpness. A re®nement of tooth measurements which are relevant to their effectiveness in penetrating and driving through food is expounded.`Tip-sharpness' is de®ned as the radius of curvature at the tip of a cusp.`Cusp-sharpness' is de®ned as the volume or surface area of the tooth per unit distance from the tip of a cusp. The experiments show that tooth shape is important in the force and energy needed for teeth to penetrate and drive through insects. Also, the scale of teeth is important ± teeth of the same shape but different size vary in their effectiveness to divide foods.

Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara)

“…It is generally agreed that Diphydontosaurus -like rhynchocephalians fed on small invertebrates [15,91,138,147-149]. This is supported by their general body size, tooth shape and build of the lower jaw.…”

The effects of relative food item size on optimal tooth cusp sharpness during brittle food item processing

“…While many measures of the efficiency of food item breakdown could be taken into account (e.g. stresses, reaction force, energy, displacement [16,17,19,33,36,37,[44][45][46][47][48]), we chose to look at the four measures of efficiency hypothesized to be correlated with tooth cusp RoC: the optimality ratio, maximum tensile stresses in the food item and enamel, and energy absorbed by the food item. The first three criteria are of particular importance during brittle food item fracture, whereas the fourth is more important during ductile fracture of foods.…”

“…Tooth cusp sharpness is commonly measured by radius of curvature (RoC), where cusps with higher RoCs are duller and cusps with lower RoCs are sharper. During interactions between single cusps and food items, sharper cusps reduce the contact area between the tooth and the food item, leading to a reduction in energy and reaction force needed to induce a fracture in the food item [14][15][16][17]. This increases the efficiency of food breakdown, but at a potential cost to the tooth.…”

Point of impact: the effect of size and speed on puncture mechanics

“…Tip morphology in a projectile will alter the relationship between kinematics and puncture found in our study, but it is not clear how. Cone shape has been shown to significantly alter puncture mechanics at slow speeds in relation to mammalian dentition [11,13] and shark teeth [16]. The results from these studies have created a strong basis for characterizing cusp form in relation to puncture, but only in slow, steady-state situations.…”

“…Energy is required to create new surfaces in materials, so cutting is controlled by the transfer of energy between the cutting tool and the target material [10]. Energy transfer during cutting has been used as a basis for studies examining how tool shape affects fracture creation [11][12][13][14][15][16], food item reduction (i.e. [17][18][19]) and wear patterns on cutting implements (i.e.…”