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 >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.身体表面沾染污染物会对多项生理功能造成负面影响。昆虫已演化出多种清除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构造。本研究以红足弓背蚁（Camponotus rufifemur）的触角清洁器（antenna cleaner）为对象，该结构为钳状构造，由基跗节（basitarsus）上的凹槽与胫节（tibia）上的突刺相对组成，二者均带有表皮（cuticular）梳状结构与刷状结构。蚂蚁会将单根触角紧密夹持于凹槽与突刺之间，拉动其通过该结构，随后再用口器对触角清洁器自身进行清洁。我们通过将凹槽或突刺在沾染了荧光颗粒的触角上移动，模拟清洁动作。实验结果显示，凹槽清除颗粒的效率高于突刺，但二者在首次清洁动作中即可去除超过60%的污染物。去除刚毛、刷状结构与梳状结构后，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颗粒，我们对活蚁的触角进行污染物沾染，并在其完成首次清洁动作后立即实施麻醉。不同尺寸的微珠被捕获在凹槽的不同区域，这与表皮突起间的间隙宽度相符。这表明触角清洁器的运作方式类似一系列筛网：先移除最大的物体，再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。