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.

体表污染会对多种生理功能产生负面影响。昆虫已演化出多种清除体表污染物的适应性策略，包含可实现被动自清洁的体表结构，以及用于主动清洁的特化构造。本研究以红足弓背蚁（Camponotus rufifemur）的触角清洁器（antenna cleaner）为研究对象，该结构为钳状构造，由基跗节（basitarsus）上的凹槽与胫节（tibia）上的突刺相对构成，二者均带有表皮梳状结构与刷状结构（cuticular combs and brushes）。蚂蚁会将单根触角紧紧夹在凹槽与突刺之间，拉动触角通过该结构完成清洁动作，随后再用口器清洁该触角清洁器本身。我们通过将凹槽或突刺在沾染了荧光微粒的触角表面移动，模拟蚂蚁的清洁冲程。实验结果显示，凹槽清除微粒的效率高于突刺，但二者在首次清洁冲程中均可去除超过60%的污染物。对刚毛、刷状结构与梳状结构进行切除处理后，清洁效率大幅下降，表明这些结构对清洁过程至关重要。为探究梳状与刷状结构如何清除不同尺寸的污染物，我们对活蚂蚁的触角进行污染处理，并在其完成首次清洁冲程后立即实施麻醉。不同尺寸的微球会被困在凹槽的不同区域，这与表皮突起间的间隙宽度相符。该结果提示，触角清洁器的运作方式类似一系列分级筛：优先清除最大尺寸的物体，随后依次处理更小的颗粒，直至最小的微粒通过粘附作用被捕获。