Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 9, 24118 Kiel, Germany.
Department of Systematic Entomology, Graduate School of Agriculture, Hokkaido University, 060-8589 Sapporo, Japan.
J R Soc Interface. 2023 Aug;20(205):20230324. doi: 10.1098/rsif.2023.0324. Epub 2023 Aug 16.
Green dock beetles exhibit sexual dimorphism in tarsal attachment setae: females have only pointed, lanceolate and spatula-like setae, while males additionally possess discoidal ones. The sexual dimorphism is probably attributed to the necessity of male discoidal setae to adhere to the smooth back of the female during copulation. We aimed to understand its possible mechanism of attachment with . Pull-off forces of both females and males were measured on (i) alive females, (ii) dead and dried females, and (iii) resin replicas of fresh females. The attachment ability tended to increase on dead and replicated female surfaces in both sexes, which indicates that the epicuticular grease layer on the integument of alive intact beetles decreases the attachment. This tendency was prominent in females. The present study clearly showed that in discoidal setae enable the males to adhere stronger to female surfaces. The divergent performance found between the sexes differing in their setal composition is probably caused by the stiffness difference between the setae types and by the specific shape of the setal tips. A peculiar reproductive biology in is probably attributed to this remarkable divergence of labour in their attachment pads between the sexes.
青 dock 甲虫跗节附肢刚毛存在明显的雌雄二型性：雌性只有尖、矛状和匙状刚毛，而雄性还额外具有盘状刚毛。这种雌雄二型性可能归因于雄性盘状刚毛在交配时需要附着在雌性光滑的背部。我们旨在用 来理解其可能的附着机制。我们在（i）活体雌性、（ii）死亡干燥雌性和（iii）新鲜雌性的树脂复制品上测量了雌性和雄性的脱落力。在两性中，死亡和复制雌性表面的附着能力往往会增加，这表明在完整活体甲虫的表皮上的表皮油脂层会降低附着性。这种趋势在雌性中更为明显。本研究清楚地表明，在 中，盘状刚毛使雄性能够更强地附着在雌性表面。在附肢结构组成上存在差异的两性之间的这种发散性能可能是由刚毛类型的硬度差异以及刚毛尖端的特定形状引起的。这种在附着垫上的两性之间显著的劳动分工差异可能归因于其独特的繁殖生物学。
