In most cases anything that looks like an ant is an ant. But there are also many insects and arachnids that mimic ants. Read on to learn more about this amazing mimicry.
Ants are incredibly abundant and dominant organisms throughout the world. Conservative estimates of their worldwide numbers range from 1 million billion to 10 million billion and between 15% and 20% of terrestrial animal biomass is ant biomass. Their huge numbers and ecological dominance make them attractive targets for other animals to parasitize in any way they can.
More than 2000 arthropod species, including many spiders, hemipteran bugs, and staphylinid beetles have evolved to look and behave just like ants in order to blend in and be accepted into colonies. Once there, they may derive protection from being surrounded by friendly ants, they may steal food from the colony, or they might even prey upon the ants and their eggs. Check out this post on velvet ants to find out about a type of wasp that sometimes mimics ants but is often confused with them.
These Salticid spiders are ant mimics. Notice how they use their front pair of legs as "antennae" because they do not have true antennae. Photos from http://natural-japan.net/?cat=35 and http://en.wikipedia.org/wiki/Ant_mimicry
The ant Pseudomyrmex salvini (left) and a mimicking spider in the genus Synemosyna (right). Photos courtesy of D. Ballhorn.
The ant-mimicking spider, Aphanlochilus rogersi, with a captured Cephalotes pusillus. Photo from http://www.alexanderwild.com/
This wonderful picture by Alex Wild shows the predatory ant-mimicking spider, Aphanlochilus rogersi, holding one of its victims snatched from a column of foraging Cephalotes pusillus. These spiders are so specialized as predators of these ants that they refuse to eat other types of insects. They not only blend in with ants by looking like them, they will also hold their catches in a way that makes it look like they are just another member of the colony holding a deceased companion. But looking like ants can also help arthropods in a very different way.
It turns out that most ant mimics do not eat ants. So then why do they look exactly like them? Many species of ants are aggressive, well armed with stingers and a powerful bite, are often distasteful, and have the amazing ability to recruit their nestmates to help when they are attacked. These features along with their huge abundance make them intimidating to predators and ideal models for other, less well protected, species to mimic.
Though it looks very similar to an ant, this is actually a cricket in the genus Macroxiphus. Photo from http://en.wikipedia.org/wiki/File:Macroxiphus_sp_cricket.jpg.
In order to successfully integrate themselves into colonies, many ant mimics hide out in the ant nest that they plan to infiltrate for days before exposing themselves to the ants living there in order to absorb the smell of the nest. Ants depend largely on smell to identify nestmates, particularly in the darkness of the colony interior, so by smelling like the nest, mimics protect themselves even further. Recently, it was found that an ant larvae mimicking butterfly, Maculinea rebeli, actually mimics ant acoustic signals as well! The larvae of these butterflies mimic the scent and begging behavior of ant larvae and are carried into nests by unsuspecting ants. Once there, they start making sounds very similar to ant queens. Using this sound means that they are treated even better than the average ant larva because the nurse ants think that they are royalty!
Though termites do not mimic ants, they are often confused with them because they are both social insects that live together in large colonies. Check out our post on termites to find out more about them.
The many types of ant mimicry in a variety of organisms makes ants seem even more impressive. Everybody seems to want to be like them.
Ben Rubin & the AntAsk Team