It looks like a colorful plant and moves like an ant: the jumping spider Siler collingwoodi mimics other life forms to avoid predation. There is, however, quite a bit to be said about his ant imitation; his brightly colored body makes him look out of place with black and brown ants anyway, and his strides are too generic to resemble those of one specific ant species. Still, the jumping spider has an advantage mimicry, write Chinese researchers in a journal iScience: he knows how to escape from hostile predatory jumping spiders. Only the praying mantis is still too smart for him.
Mimicry is an evolutionary adaptation in which certain species mimic other species in order to escape a predator or lure prey into a trap. There are different types of mimicry, of which Bates’s mimicry is one of the better known: a harmless species mimics a dangerous species. An example is yellow-black striped hoverflies, whose pattern gives the impression that they sting, but do not.
walk
Jumping spiders also show Bates mimicry: there are several species that can perfectly imitate a certain ant species. But with Siler collingwoodi such perfection appears to be out of the question. While individual spiders hold their front legs up as if they were antennae, and they imitate an ant’s step (including by gently moving the abdomen up and down), there is no one specific species to which they correspond.
Instead, they appear to adapt as closely as possible to the species they are currently in close proximity to; especially with smaller ant species they do quite well. Such a good-is-good-enough imitation still increases the chance of their survival, the researchers conclude on the basis of experiments in which they removed a few spider legs – as a result, the walk could no longer be faithfully imitated.
An additional advantage for Siler collingwoodi seems strikingly enough to be the bright color. Males are cyan blue with red spots, females are either blue-and-red or gold colored. This makes them resemble the vegetation among which they live and hunt, in particular the plant species Ixora chinensis and Carmona microphylla.
Enemies
The first has red flowers, the second has glossy leaves that seem to have a golden sheen with a little imagination. This camouflage gives them extra protection, the researchers write. This does not apply against a white background, according to one of the experiments: spiders painted black have a better chance of surviving there than colorful spiders, presumably because, in combination with their walk, they look even more like ants.
As for the enemies: the survivability of Siler collingwoodi was both determined in close proximity to the predatory jumping spider species Portia labiata like the Asian praying mantis Gonypeta brunneri. And although the mimicry and camouflage worked well to deceive the predatory spider, the advantage did not apply to the praying mantis: it still managed to outwit the jumping spiders.