Voigt Dagmar, Tsipenyuk Alexey, Varenberg Michael
Institute for Botany, Technische Universität Dresden, 01062 Dresden, Germany.
Department of Mechanical Engineering, Technion-Israel Institute of Technology, Technion City, 32000 Haifa, Israel.
R Soc Open Sci. 2017 Sep 13;4(9):171108. doi: 10.1098/rsos.171108. eCollection 2017 Sep.
Similar to other leaf beetles, rosemary beetles exhibit a distinct sexual dimorphism in tarsal attachment setae. Setal discoid terminals occur only in males, and they have been previously associated with a long-term attachment to the female's back (elytra) during copulation and mate guarding. For the first time, we studied living males and females holding to female's elytra. Pull-off force measurements with a custom-made tribometer featuring a self-aligning sample holder confirmed stronger attachment to female elytra compared with glass in both males and females; corresponding to 45 and 30 times the body weight, respectively. In line with previous studies, males generated significantly higher forces than females on convex elytra and flat glass, 1.2 times and 6.8 times, respectively. Convex substrates like elytra seem to improve the attachment ability of rosemary beetles, because they can hold more strongly due to favourable shear angles of legs, tarsi and adhesive setae. A self-aligning sample holder is found to be suitable for running force measurement tests with living biological samples.
与其他叶甲类似，迷迭香叶甲跗节附着刚毛表现出明显的两性异形。盘状刚毛末端仅出现在雄性个体中，此前人们认为这与交配和配偶保卫期间雄性长期附着在雌性背部（鞘翅）有关。我们首次对附着在雌性鞘翅上的活体雌雄个体进行了研究。使用配备自对准样品架的定制摩擦计进行的拉脱力测量证实，与玻璃相比，雌雄个体对雌性鞘翅的附着更强；分别相当于体重的45倍和30倍。与之前的研究一致，在凸形鞘翅和平板玻璃上，雄性产生的力显著高于雌性，分别为1.2倍和6.8倍。像鞘翅这样的凸形底物似乎提高了迷迭香叶甲的附着能力，因为由于腿部、跗节和粘性刚毛的有利剪切角度，它们能够更牢固地附着。结果发现，自对准样品架适用于对活体生物样品进行力测量测试。
