Confocal microscopy methods have been employed to image the metathoracic trochanter, a small exoskeleton segment between the coxa and femur, of an adult cockroach, Periplaneta americana. The confocal images represent planar sections through the exoskeleton of the trochanter. Specia-lized software was implemented to convert the section images into a complete three-dimensional geometric model of the trochanter. The raster image data of the confocal model was exported in a vector file format. Custom software was developed to resample the vector data and to automatically create a finite element mesh. The resulting mesh contained first-order, three-dimensional, triangular plate elements and also encoded data for element thicknesses. The Algor finite element package was used to analyze the model under the conditions of several biologically pertinent experiments. Special emphasis was placed on the strain analysis of the four groups of campaniform sensilla on the trochanter. These sensory organs respond to strains in the exoskeleton and are instrumental in the control of natural walking in insects. The results were compared to data from biological experiments which confirmed hypotheses and answered questions that have been difficult to determine experimentally on the animal. Functional differentiation both between groups and within groups of sensilla was observed. Further evidence that strain measurements are used in positive feedback control of the trochanteral extensor muscles was discovered. The structure of the trochanter was analyzed in the context of the function of the campaniform sensilla. Previously undescribed quantitative stress and strain data for insect cuticle was recorded.

(далее…)

Категория: Научные статьи | Нет комментариев »