After your first glance at this creature, what did you think you were looking at? An ant? A spider? Now look closely. What do you see exactly? How many legs? What do the mouthparts look like? This image is extra confusing because the predator has caught prey, so there is an extra pair of wings and some legs that do not belong to the animal. This critter is an ant-mimicking jumping spider.
While insects have three body parts — a head, a thorax and an abdomen — a spider has only two, a cephalothorax and abdomen. The ant-mimicking jumping spider has cleverly grown so its cephalothorax is constricted in the center to look more like two separate parts instead of one.
Insects have six legs and antennae. Spiders have eight legs but no antennae. Spiders also have two chelicerae, or jaws, and two pedipalps, or arms. The ant-mimicking jumping spider’s two front legs are curved to look more like antennae.
Why an ant?
There are animals around the globe that specialize in eating ants, such as anteaters and aardvarks. But ants are known for being very aggressive, and most ants produce formic acid, which makes them smell and taste very bad. Here in Will County, there are a lot of species that avoid eating ants but would love to feast on a spider. So for this spider species, looking like an ant protects it from many potential predators, such as birds and other spiders.
Interestingly, while mimicking the ant gives this spider protection, the ant it mimics is one of its only predators. But clearly it is worth it for this spider-in-disguise. The spider takes advantage of the odors the ants give off by living and nesting close by. But when they nest, they use their strong silk to create an impenetrable fortress that the ants can’t get into.
Two starring roles
Ant-mimicking jumping spiders mimic two different species of ants during their lifecycle. When they are young, they look just like a tiny black ant from the genus Crematogaster. In their adult form, they mimic a larger ant from the genus Camponotus.
Not only are their bodies shaped to look more antlike, but they also play the part. In fact, these jumping spiders have taken their role of an ant so seriously that they have lost their ability to jump. Although they still use all eights legs to walk, every once in a while, they stop and wave their first pair of legs in the air to mimic the antennae of ants. They also imitate how ants wander in little spurts as they follow chemical signals.
Both the juvenile and adult spider look like an ant from above. This is where most flying predators would see them. The juvenile spider also looks like the ant it mimics in profile, or from the side view. However, the adult ant looks more spiderlike in profile. This is because they need to attract a mate.
Words to know
Aggressive: Ready to attack.
Elaborate: Detailed or complicated.
Imitate: To copy or follow as a model.
Impenetrable: Impossible to enter or pass through.
Mimic: To imitate or copy.
Odor: A distinctive smell.
Wander: To walk aimlessly or casually.
Besides their leaping abilities, jumping spiders are known for their elaborate mating dances. Scientists have not determined yet if this ritual was also lost so the spiders look more antlike. So far, they have only observed a secret wave the adults give each other to let them know they are really a spider.
Miniscule mimickers
Their favorite habitat is bushes and tall grasses, but even knowing that, it will still be tricky to spot these ant lookalikes. They are extremely tiny. The largest a female gets is about 1/4 of an inch, and a full-grown male will top out at a mere 3/16 of an inch. So next time you see what appears to be a tiny ant, take a closer look. Are there really only six legs?
Although you may not observe these tiny critters, the Will County Forest Preserve District is hosting two hikes where you can explore and learn more about our eight-legged friends:
Spider Hike: 7:30 to 8:45 p.m. Friday, Sept. 9, at Four Rivers Environmental Education Center.
Night Hike: Spotlight on Spiders: 7 to 8:30 p.m. Friday, Oct. 14, at Plum Creek Nature Center.
Spiders not your thing? Check out all our upcoming programs on our event calendar.
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