Insect Camouflage
If you are an insect, odds are some animal is trying to eat you. How do insects avoid being some other hungry animal’s dinner? Insects have developed a number of interesting mechanisms to avoid predators. One of those mechanisms is mimicry. Several species of insect have evolved to mimic the morphology or color scheme of other insects known to be harmful. Predators who see these insects mistake them for ones that are toxic or otherwise harmful, and stay away. Mimicry, as such, is a useful mechanism for survival and can be selected for by evolution
Strictly speaking, mimicry does not have to be visual. Mimicry can be auditory or olfactory. Biologists have identified 3 major types of mimicry among insects: Batesian, Müllerian, and Wasmannian, each named after the biologists who first proposed their concepts.
Batesian Mimicry
Batesian mimicry consists of a harmless organism (mimic) evolves to mimic the warning signs of other harmful species (model). It is the simplest and most commonly encountered form of insect mimicry. As an example, hoverflies are a species of fly in the family Syrphidae. Hoverflies have evolved to mimic the color pattern and body shape of bumblebees. Because of this, predators mistake them for bees and leave them alone because they do not want to be stung. In actuality though, hoverflies cannot sting and are completely harmless. Mimicking the color and shape of a harmful species allows them to operate unthreatened, and gives them an evolutionary advantage.
Müllerian Mimicry
Müllerian mimicry, named after the German entomologist Fritz Müller, occurs when two separate harmful species evolve to mimic the color patterns and warning signs of each other. Two unprofitable insects, most often distasteful, can evolve to resemble each other and mimic each other distinguishing features. The evolutionary benefit is that predators can learn to avoid both species of insects with fewer experiences. Two species mimicking each others’ honest warning signals gives predators a double dose of information that tells them “stay away!”
Several species of Heliconius butterfly (see related species here), for instance, have evolved to mimic each other warning signals. The mimicking is mutually advantageous because predators learn to avoid both species of butterfly in a fewer amount of encounters.
Wasmannian Mimicry
Some insects mimic not only to avoid predators, but to gain the benefits of living among another species. Wasmannian mimicry occurs when one species evolves to look like another species in order to live commensally or parasitically among them. The majority of Wasmannian mimicry occurs in species in the Hymenopterafamily; i.e. ants, bees, wasps, and termites. Eusocial insects like Hymenopterahave a robust social structure to take advantage of.
For example, the longhorn beetle Euderces pinihas evolved to look like the acrobatic ant Crematogaster laeviuscula. E. pinimimics the appearance of the acrobat ant so that it can gain access to its nest and food supply; sometimes even eating the ants they live among. The mimicry is also a form of Batesian mimicry, as mimicking the ant’s appearance keeps predators away.
