Tarantulas and black widows may cause human Miss Muffets to get off their tuffets, but several studies show that many spiders themselves run for their lives if they encounter Myrmarachne melanotarsa, a gregarious jumping spider that pretends to be an ant.
The jumping spider is not the only faux ant. A new Phys Org report notes that there are more than 300 species of spider that mimic the outward appearance of ants.
The jumping spider looks like, acts like, and hangs out with ants, even forming mini, colony-type gangs to foil their own predators.
Most spiders are afraid of ants, and they even fear these fake ants that are really spiders.
"Ants are very dangerous to arthropods," Ximena Nelson, of the University of Canterbury, told Discovery News. Nelson is one of the world's leading experts on myrmecomorphy, or resembling an ant.
Nelson said ants "are social and can mount a strong response if alerted to potential danger, and they have strong mandibles and are extremely lethal to many spiders. Many ants also contain formic acid, which they can use for defense by squirting it on potential predators, causing considerable harm."
Spiders that make the mistake of putting an ant in their mouths, she added, often spit them out immediately, suggesting that "ants don't taste good either."
What's an ant-loathing spider to do, then, to avoid being bullied? Mimicry comes into play, because it's a case of "if you can't beat them, join them."
Many animals impersonate other species temporarily. Some birds, for example, copy avian songs that aren't their own. Cats sometimes chatter like birds, presumably to fool their potential prey. Even hunters sometimes don camouflage clothing to disguise themselves.
Evolving a permanent new body to facilitate mimicry, however, takes deception to a whole new level.
Nelson believes the ant-resembling jumping spider evolved its ant-like ways over a long period of evolution "in which each morph that resembled ants more was selected for and morphs that did not resemble ants were selected against."
The deception works better if the fake ant behaves like an actual ant too, so natural selection appears to have also selected for spiders within this species that act like ants. The end result is a spider that is the spitting image of an ant.
Spider expert Paula Cushing, of the Denver Museum of Nature & Science, told Discovery News that insects and spiders that mimic ants "are well protected from their own potential predators" since "ants are often unpalatable prey for arthropod predators or are not attractive as prey due to their aggressive behavior towards intruders and their ability to sting and bite animals that attack them."
There's yet another perk to looking like an ant, at least for M. melanotarsa. This ant mimic spider is so feared that female spiders from other species will flee when they see it, even abandoning their broods, which the fake ant then consumes as an easy snack.