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Biology subjects

Kubo, M. O.

Publications and source records attributed to Kubo, M. O..

2 recordsLinked to original sources

Inter-microscope comparability of dental microwear texture data obtained from obtained from different optical profilometers.

Dental microwear texture analysis has become a well-established approach for dietary inference and reconstruction of mammals and other tetrapods, both extant and extinct. As the amount of available data grows immensely, researchers could benefit from combining data gathered by others to perform meta-analyses. However, different devices used to capture three-dimensional surface scans for DMTA are known to produce variation even when measuring the same surface. Here we compare DMTA data of 36 guinea pigs that received different diets in a controlled feeding experiment, measured on a confocal disc-scanning and a confocal laser-scanning microscope. We are testing different pre-analysis filtering protocols to mitigate differences. We find inter-microscopes and filter-related differences for the majority of analysed 41 DMTA parameters. Certain microscope-specific filter routines resulted in less differences than other pre-analysis protocols. We further identify DMTA parameters which were stable regardless of microscope or pre-analysis treatment. Overall, the results obtained on both microscopes show the same dietary differentiation between guinea pig feeding groups, which supports that DMTA is a suitable method to obtain repeatable, objective dietary inferences. We finally propose a roadmap to enhance data exchange and inter-lab comparability and collaboration in the future.

ecology↗

Variation and mechanisms of life history evolution in insular dwarfism as revealed by a natural experiment

Islands are a classic focus for evolutionary studies. One subject of much interest has been the evolution of "dwarfs", significantly smaller island mammals relative to their continental counterparts. Although a consensus has been achieved that multivariate ecological causes are behind body size changes, the processes involved remain largely unexplored. Life history variables, including the age of first reproduction, growth rate, and longevity, are probably key to understanding the process of insular dwarfism. The Japanese Archipelago with numerous islands offers a unique natural experiment of evolution into different sizes within the same group of organisms, deer. Thus, we investigated eight deer populations with a total number of 52 individuals exhibiting body size variation, both extant and fossil, to clarify the effect of insularity on life history traits. We applied several methods to both extant and extinct populations to resolve life history changes among deer populations. Skeletochronology, using lines of arrested growth formed in long bones (femur and tibia), successfully reconstructed body growth curves and revealed a gradual change in growth trajectories reflecting the degree of insularity. Slower growth rates with prolonged growth periods in more isolated deer populations were revealed. An extensive examination of bone microstructure further corroborated this fact, with much slower growth and later somatic maturity evident in fossil insular deer isolated for more than 1.5 Myr. Finally, mortality patterns assessed by demographic analysis showed variation among deer populations, with a life history of insular populations shifting toward the "slow life".

evolutionary biology↗