Bee lice (Braulidae) are small parasitic flies, which are adapted to live on their bee host. As such, the wingless Braula coeca is a parasite of the common honey bee Apis mellifera and it is well adapted to attach to its hairy surface. The attachment system of B. coeca provides a secure grip on the fine setae of the bee. This is crucial for the parasite survival, as detachment from the host is fatal for the bee louse. The feet morphology of B. coeca is well adapted to the challenging bee surface, notably by strongly broadened claws, which are split into a high number of comb-like teeth, perfectly matching the diameter of the bee hairs. Based on microscopy observations, both the morphology and material composition of the tarsi of B. coeca are characterized in detail. Using high-speed video analysis, we combine the morphology data on the attachment system with a behavioural context. Furthermore, we directly measured the attachment forces generated by the bee lice in contact with the host. In particular, the claws are involved in attachment to the host, as the interstices between the teeth-like spines allow for the collection of several hairs and generate strong friction, when the hairs slip to the narrow gap between the spines. The overall morphology of the tarsus produces strong attachment, with average safety factors (force per body weight) around 1130, and stabilizes the tarsal chain with lateral stoppers against overflexion, but also allows for the fast detachment by the tarsal chain torsion.

中文翻译：

---

外寄生蜂虱 Braula coeca (Diptera, Braulidae) 对蜜蜂的特殊附着能力

蜂虱（Braulidae）是一种小型寄生蝇，它们适应生活在它们的蜜蜂宿主身上。因此，无翅Braula coeca是普通蜜蜂Apis mellifera的寄生虫，它非常适合附着在其毛茸茸的表面。B. coeca的附着系统可牢固地抓住蜜蜂的细刚毛。这对于寄生虫的生存至关重要，因为与宿主分离对蜂虱来说是致命的。B. coeca的足部形态很好地适应了具有挑战性的蜜蜂表面，特别是通过强烈加宽的爪子，这些爪子分成大量的梳状牙齿，与蜜蜂毛发的直径完美匹配。根据显微镜观察，跗节的形态和材料组成B. coeca进行了详细的表征。使用高速视频分析，我们将附件系统上的形态数据与行为上下文相结合。此外，我们直接测量了蜂虱与宿主接触产生的附着力。特别是，爪子与宿主的附着有关，因为齿状刺之间的空隙允许收集几根毛发并产生强烈的摩擦力，当毛发滑到刺之间的狭窄间隙时。跗骨的整体形态产生很强的附着力，平均安全系数（每体重的力）约为 1130，并通过侧向止动器稳定跗链防止过度弯曲，但也允许跗链扭转快速脱离。