Data from: Functional morphology and efficiency of the antenna cleaner in Camponotus rufifemur ants

Contamination of body surfaces can negatively affect many physiological functions. Insects have evolved different adaptations for removing contamination, including surfaces that allow passive self-cleaning and structures for active cleaning. Here, we study the function of the antenna cleaner in Camponotus rufifemur ants, a clamp-like structure consisting of a notch on the basitarsus facing a spur on the tibia, both bearing cuticular 'combs' and 'brushes'. The ants clamp one antenna tightly between notch and spur, pull it through, and subsequently clean the antenna cleaner itself with the mouthparts. We simulated cleaning strokes by moving notch or spur over antennae contaminated with fluorescent particles. The notch removed particles more efficiently than the spur, but both components eliminated more than 60% of the particles with the first stroke. Ablation of bristles, brush and comb strongly reduced the efficiency, indicating that they are essential for cleaning. To study how comb and brush remove particles of different sizes, we contaminated antennae of living ants, and anaesthetized them immediately after they had performed the first cleaning stroke. Different-sized beads were trapped in distinct zones of the notch, consistent with the gap widths between cuticular outgrowths. This suggests that the antenna cleaner operates like a series of sieves that remove the largest objects first, followed by smaller ones, down to the smallest particles that get caught by adhesion.身体表面的污染物会对多种生理功能产生负面影响。昆虫演化出了多种清除体表污染物的适应性策略，包括可实现被动自清洁的体表结构，以及用于主动清洁的特化结构。本研究以红足弓背蚁（Camponotus rufifemur）的触角清洁器为研究对象，该结构呈钳状，由基跗节上的凹槽与胫节上的突刺相对组成，二者均分布有表皮特化的梳状结构与刷状结构。蚂蚁会将一根触角紧密夹在凹槽与突刺之间，拉动触角穿过该结构，随后再用口器清洁自身的触角清洁器。我们通过将凹槽或突刺在沾染荧光颗粒的触角上移动，模拟清洁动作。相较于突刺，凹槽的颗粒清除效率更高，但二者在首次清洁动作中即可去除超过60%的附着颗粒。对刚毛、梳状与刷状结构进行切除后，清洁效率大幅下降，表明这些结构是清洁过程的核心要件。为探究梳状与刷状结构如何清除不同尺寸的颗粒，我们对活体蚂蚁的触角进行污染物沾染，并在蚂蚁完成首次清洁动作后立即对其实施麻醉。不同尺寸的微球会被卡在凹槽的不同区域，这与表皮突起间的间隙宽度相匹配。由此可见，该触角清洁器的工作机制类似一系列筛网：优先移除最大的附着物，再依次清除更小的颗粒，直至最小的微粒通过粘附作用被捕获。