Archive - November 2020

What Are the Components of Mimicry?

For mimicry to occur there must be three components.

The "mimic" is the organism that looks, sounds, smells or behaves like something else.

The "model" is the organism or object that the mimic looks, sounds, smells or behaves like.

The "receiver" is the organism that notices the deception and acts as it would toward the model. The receiver is often a predator or potential prey item. 

Mimesis
In mimesis, the mimic looks like a nonliving thing. For example, a walking stick insect looks and acts like a twig of a woody plant. The giant swallowtail butterfly's (Papilio cresphontes) larva looks like bird droppings. The comma butterfly (Polygonia comma) looks like dead leaves, especially when it lands on dead leaves and doesn't move much. Camouflage can be considered a type of mimesis. The advantage of mimesis is protection of the mimic from predators.

Batesian Mimicry
In this type of mimicry, the harmless mimic poses as harmful. The advantage to the mimic is to avoid harmful encounters, mainly from predators. Harmless hoverflies mimic the appearance of wasps and are often seen at the same flowers as wasps. Hummingbird clearwing moths (Hemaris thysbe) and snowberry clearwing moths (Hemaris diffinis) resemble bumble bees, but the clearwing moths cannot sting. The larva of the spicebush swallowtail butterfly (Papilio troilus) looks somewhat like a smooth greensnake (Opheodrys vernalis).

Müllerian Mimicry
The model and the mimic in Müllerian mimicry are both harmful, and it is often difficult to tell which one is the mimic and which one is the model. They both use the same method to make themselves known as harmful in order to avoid potentially deadly encounters. This system confuses predators while benefitting both mimic and model. The monarch butterfly (Danaus plexippus) and the viceroy butterfly (Limenitis archippus) are not closely related, but they are very similar in coloration and behaviors. Both of them are unpleasant to the taste of predators that try to eat them. If a predator has a bad experience with one of these species, it may avoid both species in the future. The viceroy is the model in this example because it is more distasteful than the monarch. 

Aggressive Mimicry
Aggressive mimicry involves the mimic using a trait from the model as a lure. The advantage is to attract unwitting prey items. Female fireflies of the genus Photuris emit the same light signals as females of the firefly genus Photinus. Female fireflies of the genus Photinus use these signals to show males of their type that the female is ready to mate. The males then come to them for that purpose. The females of the genus Photuris use the signals to attract males of the genus Photinus and a few other firefly groups, and then catch and eat them.

Another example of this type of mimicry is shown by the alligator snapping turtle (Macrochelys temmnickii). It has a "lure" in its mouth that looks and moves like a worm. As the turtle sits on the bottom of the water body, it holds its mouth open and wriggles the "worm" so that a fish may see it and be attracted to it. If the fish swims into the turtle's mouth, the turtle eats it. The turtle has not invested much effort to provide itself with some food.    

Inter-sexual Mimicry
In inter-sexual mimicry, the individuals of one sex in a species mimic the members of the opposite sex. The bluegill (Lepomis macrochirus) is one of several sunfish species that exhibits this behavior. Small male bluegills that have been unable to establish their own territory may still reproduce by sneaking into the territory of a larger male. The small male can fertilize eggs when the larger male is occupied with something else or by behaving like a female to fool the larger male.

Automimicry
Automimicry occurs when one part of an organism's body resembles another part of its body. The gray hairstreak butterfly (Strymon melinus) uses the extensions and markings on its hindwings to create a false head. This butterfly often perches upside down. The tails then resemble antennae, and the markings look like eyes on a head. Moving the wings increases the effect. Predators often go for this section of the butterfly instead of the more vital parts of the body, allowing the butterfly a chance to escape. The predator may be satisfied, too, with a chunk of hindwing instead of the entire butterfly.