The Monarch Butterfly is a species from the Danaus genus. It is resident in North America, Central and Northern South America, the Canary Islands, the Azores, and Madeira, and is found as an occasional migrant in Western Europe and a rare migrant in the United Kingdom, as well in some parts of Australasia. Their bright colours indicate the presence of a toxin, milkweed.
The Monarch’s wingspan ranges from 8.9–10.2 cm (3½–4 in.). The upper side of the wings is tawny-orange, the veins and margins are black, and in the margins are two series of small white spots. The fore wings also have a few orange spots near the tip. The underside is similar but the tip of the fore wing and hind wing are yellow-brown instead of tawny-orange and the white spots are larger. The male has a black patch of androconial scales responsible for dispersing pheromones on the hind wings, and the black veins on its wing are narrower than the female’s. The male is also slightly larger.
Monarchs are especially noted for their lengthy annual migration. In North America they make massive southward migrations starting in August until the first frost. A northward migration takes place in the spring. The monarch is the only butterfly that migrates both north and south as the birds do on a regular basis. But no single individual makes the entire round trip. Female monarchs deposit eggs for the next generation during these migrations. After these eggs are deposited, the female monarch who deposited them dies.
The Monarch can be found in a wide range of habitats such as fields, meadows, prairie remnants, urban and suburban parks, gardens, trees, and roadsides. It overwinters in conifer groves.
Males will also take in moisture and minerals from damp soil and wet gravel, a behavior known as mud-puddling. The Monarch has also been noticed puddling at an oil stain on pavement.
The mating period for the overwinter population occurs in the spring, just prior to migration from the overwintering sites. The courtship is fairly simple and less dependent on chemical pheromones in comparison with other species in its genus. Courtship is composed of two distinct stages, the aerial phase and the ground phase. During the aerial phase, the male pursues, nudges, and eventually takes down the female. Copulation occurs during the ground phase where the male and female remain attached for about 30 to 60 minutes. A spermatophore is transferred from the male to the female. Along with sperm, the spermatophore is thought to provide the female with energy resources that aid her in carrying out reproduction and remigration. The overwinter population returns only as far north as they need to go to find the early milkweed growth; in the case of the eastern butterflies that is commonly southern Texas. The life cycle of a monarch includes a change of form called complete metamorphosis. The monarch goes through four radically different stages including:
- Egg- This is the first stage in the life cycle of a monarch. Monarch eggs are deposited on leaves and are minuscule.
- Larva- This is the second stage in the life cycle of a monarch. Monarch larva are called caterpillars. Monarch caterpillars are yellow with black-and-white stripes. They eat lots of milkweed to prepare for the next stage.
- Pupae- This is the third stage in the life cycle of a monarch. This is when a monarch caterpillar makes a green cocoon.
- Adult- This is the fourth and final stage in the lif cycle of a monarch. This is when a monarch caterpillar finally emerges from it's cocoon and becomes a butterfly. But, this butterfly cannot fly yet because it's wings are wet. Which also means it is vulnerable prey for a bird. When the wings are dry, the butterfly flies away and then the whole cycle starts all over again.
n North America, monarchs migrate both north and south on an annual basis, in a long-distance journey that is fraught with risks. The population east of the Rocky Mountainsattempts to migrate to the sanctuaries of the Mariposa Monarca Biosphere Reserve in the Mexican state of Michoacán and parts of Florida. The western population tries to reach overwintering destinations in various coastal sites in central and southern California. The overwintered population of those east of the Rockies may reach as far north as Texas and Oklahoma during the spring migration. The second, third and fourth generations return to their northern locations in the United States and Canada in the spring. Captive-raised monarchs appear capable of migrating to overwintering sites in Mexico, though they have a much lower migratory success rate than wild monarchs do. See section on captive-rearing below. Monarch overwintering sites have been discovered recently in Arizona. Monarchs from the eastern US generally migrate longer distances than monarchs from the western US.
Monarchs share the defense of noxious taste with the similar-appearing viceroy butterfly in what is perhaps one of the most well-known examples of mimicry. Though long purported to be an example of Batesian mimicry, the viceroy is actually reportedly more unpalatable than the monarch, making this a case of Müllerian mimicry.