There are many theories for mimicry, but a common belief is that potential predators confuse the mimic with the model insect which reduces the likelihood of being eaten. Often time the model insect will be unpalatable to others, brightly colored and conspicuous. The resemblance usually is in color, pattern, or form, but it can be solely behavioral, and the mimic occasionally may resemble a group of animals or only some part or aspect of another animal.
Common examples of mimicry include:
- Bumble bee vs Snowberry clearwing moth (Hemaris diffinis)
- Hover flies vs bees and wasps
- Greater bee fly (Bombylius major), a bee mimic
- Hover fly (Somula decora), a wasp mimic
- Monarch butterfly vs viceroy vs Queen vs Arizona viceroy
- Red spotted purple is very similar to the pipevine swallowtail and other swallowtail
Reference:
Rettenmeyer, Carl W. “Insect mimicry.” Annual review of entomology1 (1970): 43-74.