Ant-Mimicking Spider

Genus Myrmarachne — the ant-mimicking spiders — contains over 200 species worldwide and is one of the most extreme cases of arthropod mimicry documented. Despite belonging to the jumping-spider family Salticidae, Myrmarachne species do not look like jumping spiders: the body is elongated and constricted to mimic the three-segment 'head, thorax, abdomen' of an ant; the abdomen carries pseudo-segmentation that imitates the ant petiole; and the species typically hold their first pair of legs aloft and wave them in the precise rhythm of ant antennae, walking on only six legs to complete the disguise. The chemical mimicry is also remarkable: many Myrmarachne species exude cuticular hydrocarbons that match the species-specific 'colony odor' of the target ant species, allowing the spider to evade detection by ants she walks among. The mimicry serves two functions. First, defensive: most spider predators (birds, lizards, mantises, vespid wasps) avoid ants because of the formic acid spray and biting/stinging defenses, so a convincing ant-mimic spider receives the same predator avoidance. Second, predatory: some Myrmarachne species use the disguise to live among or near ant colonies and ambush ant workers — the spider walks among them unmolested, then drops on a victim from behind. The species is non-venomous to humans and harmless. Myrmarachne formicaria, the European ant-mimicking spider, is the type species for the genus and a model organism for arthropod mimicry research.