A Morpho butterfly may be one of over 80 described species of the genus Morpho. They are neotropical butterflies found mostly in South America as well as Mexico and Central America. Morphos range in wingspan from the 7.5 cm (3 inch) M. rhodopteron to the imposing 20 cm (8 inch) Sunset Morpho, M. hecuba. The name Morpho derives from its use as an epithet of Venus.
Many Morpho butterflies are coloured in metallic, shimmering shades of blue and green. These colours are not a result of pigmentation but rather are an example of iridescence: the extremely fine lamellated scales covering the Morpho’s wings reflect incident light repeatedly at successive layers, leading to interference effects that depend on both wavelength and angle of incidence/observance. Thus the colours produced vary with viewing angle, however they are actually surprisingly uniform, perhaps due to the tetrahedral (diamond-like) structural arrangement of the scales or diffraction from overlying cell layers. This structure may be called a photonic crystal. The iridescent lamellae are present on the dorsal side of their wings only, leaving the ventral side a drab brown.
Morpho butterflies feed on the juices of fermenting fruit with which they may also be lured. The inebriated butterflies wobble in flight and are easy to catch. Morphos will also feed on the bodily fluids of dead animals and on fungi. Morpho butterflies may be important by their role in dispersing fungal spores.
The hairy brown caterpillars are nocturnal and feed on a variety of leguminous plants. In some species the caterpillars are also cannibalistic, a trait thought to be a population control mechanism. If disturbed, Blue Morpho caterpillars will secrete a fluid smelling of rancid butter. The tufts of hair decorating the caterpillars irritate human skin.
The entire life cycle of the Morpho butterfly, from egg to death, is approximately 115 days. The adults live for about a month. Their predators are few for the adults retain poisonous compounds accumulated by the feeding caterpillar – a process known scientifically as sequestering.