Bess beetles are sapro-xillophagous insects that inhabit decaying logs. They display sub-social behavior and acoustic communication. Adults produce sounds with an abdomino-alary stridulatory system. The sixth abdominal tergum has lateral protuberances with spines (pars stridens), whereas the hind wings have spines in the radial cell (plectrum). The potential taxonomic utility of these spines has not been studied. We evaluated the variation of spines in the plectrum of adult females sampling four species of Proculini using traditional and geometric morphometric methods. We divided the plectrum into five zones to compare the density, size and shape of spines among zones and among species comparing each zone separately. Spine shape and size were quantified with 2D cartesian coordinates and four variables from SEM micrographs. Separate univariate and multivariate analyses of variance revealed that the size, density and shape of spines is different among zones in each of the four species. Also, spine shape and size in all zones is different among species, which would imply that plectrum spines might have taxonomic utility. Additionally, disparity analyses showed that the peripheral zones have a higher variability, and the disparity values in the middle and apex zones are higher in the two species with a wide distribution range.

贝斯甲虫是腐生的腐生虫。他们表现出非社会行为和声音交流。成人会产生腹部-腹部音调系统的声音。第六腹部的足突具侧突，有刺（pars stridens），而后翅的radial骨细胞有翼突（plectrum）。这些刺的潜在生物分类效用尚未得到研究。我们评估刺的变化在拨子成年女性使用传统和几何形态测量方法采样四种Proculini的。我们将拨杆分开分为五个区域，以比较区域之间以及分别比较每个区域的物种之间的刺的密度，大小和形状。脊柱的形状和大小由2D直角坐标和来自SEM显微照片的四个变量量化。分别的单变量和多变量方差分析表明，四种物种中每个区域的刺的大小，密度和形状均不同。而且，物种之间所有区域的脊柱形状和大小都不同，这意味着拨节棘可能具有分类学用途。此外，视差分析表明，在分布范围较广的两个物种中，外围区域的变异性较高，中间和顶点区域的视差值较高。