Mimicry in insects covers a variety of auditory, olfactory, or visual behaviors which serve to camouflage or advance some other deceptive or defensive behavior. So, the mimetic species may sound-like, smell-like or look-like its model.
Henry W. Bates, the British naturalist of the Amazon, first wrote in 1862 about mimics among palatable and unpalatable species, saying: "I never saw the flocks of slow-flying Heliconidae in the woods persecuted by birds or dragonflies... nor when at rest did they appear to be molested by lizards, or predacious flies of the family Asilidae [robber-flies] which were very often seen pouncing on butterflies of other families... In contrast, the Pieridae (sulfur butterflies), to which Leptalis belongs [now called Dismorphia] are much persecuted." This quote identifies a visual mimicry where an edible species mimics a less edible or inedible species (Barrows, 2001). The theory is called Batesian or cryptic mimicry and classically refers to situations where the mimetic does not outnumber its model; by contrast to Waldbauerian-Batesian mimicry, “in which a mimetic species is sympatric [“occupying the same geographical range without loss of identity from interbreeding,” according to M-W Online Dictionary] with its model but is more frequent that it earlier during the warm season,” according to Barrows (2001). Also, there is Browerian automimicry where “conspecific [i.e., the same] species mimic each other (e.g., in Monarch Butterflies, individuals that are more palatable look like individuals that are less palatable),” according to Barrows (2001).
Somewhat later, Dr. Johann Friedrich Theodor (“Fritz”) Müller, the German biologist who immigrated to southern Brazil, observed [see “Ueber die Vortheile der Mimicry bei Schmetterlingen,”Zoologischer Anzeiger 1 (1878): 54-55] a situation “in which both mimic and model are unpalatable for all potential predators;” but Mllerian mimicry is also used today in the sense of “mimicry between, or among, two or more distasteful, or toxic, species that reduces predation for each species because, in this resemblance situation, predators learn to avoid only one color pattern rather than several,” according to Barrows (2001). Pasteur (1985) has argued that strictly speaking, “Müllerian mimicry is not mimicry because both model and mimic are sending non-deceitful signals to a perceiver.”
In any event, the advantage of mimicry is that one species potentially survives longer by using less energy.
Edward M. Barrows, Animal Behavior Desk Reference: A Dictionary of Animal, Ecology and Evolution, 2nd ed. Boca Raton, FL: CRC Press, 2001, p. 442 and 445.
G. D. H. Carpenter and E. B. Ford. Mimicry. London: Methuen, 1933.
Georges Pasteur, “A Classificatory Review of Mimicry Systems,” Annual Review of Ecology and Systematics 13 (November 1985), p. 185.