Can Dental Microwear Textures Record Inter-Individual Dietary Variations?

Abstract

BackgroundDental microwear analyses are commonly used to deduce the diet of extinct mammals. Conventional methods rely on the user identifying features within a 2D image. However, recent interdisciplinary research has lead to the development of an advanced methodology that is free of observer error, based on the automated quantification of 3D surfaces by combining confocal microscopy with scale-sensitive fractal analysis. This method has already proved to be very efficient in detecting dietary differences between species. Focusing on a finer, intra-specific scale of analysis, the aim of this study is to test this method's ability to track such differences between individuals from a single population.Methodology/Principal FindingsFor the purposes of this study, the 3D molar microwear of 78 individuals from a well-known population of extant roe deer (Capreolus caprelous) is quantified. Multivariate statistical analyses indicate significant seasonal and sexual differences in individual dental microwear design. These are probably the consequence of seasonal variations in fruit, seed and leaf availability, as well as differences in feeding preference between males and females due to distinct energy requirements during periods of rutting, gestation or giving birth. Nevertheless, further investigations using two-block Partial Least-Squares analysis show no strong relationship between individual stomach contents and microwear texture. This is an expected result, assuming that stomach contents are composed of food items ingested during the last few hours whereas dental microwear texture records the physical properties of items eaten over periods of days or weeks.Conclusions/SignificanceMicrowear 3D scale-sensitive fractal analysis does detect differences in diet ranging from the inter-feeding styles scale to the intra-population between-season and between-sex scales. It is therefore a possible tool, to be used with caution, in the further exploration of the feeding biology and ecology of extinct mammals.

Seeds, browse, and tooth wear: a sheep perspective

“…Merceron et al. (2010) has reached the same conclusion when exploring feeding behavior throughout the year and depending on gender among a modern population of roe deer. Indeed, roebuck shot in winter while foraging a lot on fallen acorns have higher complexity of dental microwear textures than females browsing mostly on brambles semi‐persistent and mature leaves.…”

“…2007; Merceron et al. 2010, 2014; Scott 2012), we would expect the following: (1) The complexity ( Asfc ), the textural filling volume ( Tfv ), as well as the heterogeneity of complexity ( HAsfc ) to be higher and the scale of maximum complexity ( Smc ) to be lower for ewes fed with seeds as complement with clover. (2) The complexity ( Asfc ), the textural filling volume ( Tfv ), the heterogeneity of complexity ( HAsfc ) as well as the scale of maximum complexity ( Smc ) to be correlated with seed density, size and hardness.…”

Dental microwear differences between eastern and southern African fossil bovids and hominins

“…The lateral (x, y) sampling interval was 0.18 µm, vertical (z) resolution was 0.005 µm and field of view for each scan was 138x102 µm. [25][26][27] In fact, these attributes together effectively parse extant bovids into Gagnon and Chew's 28 fine-scale diet categories 29 : (1) obligate grazers (>90% monocots); (2) variable grazers (60-90% monocots); (3) browser-grazer intermediates (30-70% monocots and dicots, including some fruit); (4) generalists (>20% of each of the three food types); (5) browsers (>70% dicots only, part fruit); and (6) frugivores (>70% fruits).…”

Dental microwear texture analysis of late Pliocene Procynocephalus subhimalayanus (Primates: Cercopithecidae) of the Upper Siwaliks, India

“…The closest approximation to Procynocephalus among the extant taxa is Lophocebus, a large-bodied monkey observed to engage in hard-object feeding (e.g., seeds with stony layers and bark) and to a lesser extent, Gorilla and Cebus, both of which consume variable amounts of fracture resistant foods. Procynocephalus may have consumed foods with even harder properties than the brittle ectoderm of forest nuts and seeds, and concentrated at least some of its foraging efforts on foods close to, or underneath ground level, at least on a seasonal basis [46]. The relationship between semi-terrestriality and consumption of foods with a high Young's modulus values is in part borne out by these analyses.…”