These grip the surface the same way a rock climber might grip a cliff face with her fingertips. Each of these tarsi also has a tiny, sticky cushion. Sticky Cushions You might think that these cushions are suction cups, but they aren’t. They’re merely sticky enough to hold the minuscule weight of the insect. Flies tend to rely more on these cushions to keep them up, while ants tend to favor their sets of claws, although both insects have both sets of equipment. Their biggest aid, however, is their minuscule weight. For wall crawling, smaller is definitely better.