When considering animal migration,people typically associate it with birds and animals,When considering animal migration, people typically associate it with birds and mammals, while being quite unfamiliar with the migration patterns of insects. In fact, the monarch butterfly can compete with any bird or beast on the migration font. It surprises most people when they realize the distance these insects travel, the massive number of butterflies involved, and the special physiological changes that occur in the process.
Every autumn, the monarch butterflies in North America migrate southward to winter in warmer temperatures, only to return northward the next spring. Each single trip covers 4,000km, which makes the insects’ reputation as The King of Migration truly deserved. Toward the end of November in 2009, I was fortunate to have the chance to visit the wintering habitat of the Mexican monarch butterfly I recorded the unforgettable experience below.
Mexico is the main wintering habitat for the monarch butterfly There are many nature reserves for them with a total area of more than 790,000 hectares distributed across 22 states of the country. Most of these are located in the Mexico state and Michoacan state, the latter being most famous for its nature reserves for this butterfly Each year, these reserves are open to the public from November to the following March, everyday from 9:00am unto 6:00pm.January and February are the best months to visit for viewing the longest amount of butterflies. A week-long Butterfly Festival is held here at the end of February or the beginning of March. During this festival, visitors should book rooms well in advance and may prefer to avoid visiting on the weekends due to luge crowds.
The reserve we visited is located on the lakeside of Avandaro near VaUe tie Bravo in Mexico state. Valle tie Bravo, 156km southwest from Mexico city has no official entrance and charges no entry fee, though there are visible reserve signs along the roadways. After being advised that the journey if done on horseback, would be much shorter, each of us rented a horse and the stable groom played the role of a tour guide.
Description Danausplexppus, also caved monarch butterfly belongs to the family of Danudae. In the 19th century it was discovered in New Zealand. Due to its huge size with a wingspan of8.9cm-10.2cm, and for its vast distribution range, Samuel H. Scudder named it the monarch butterfly in memory of Wiliam M, the king of England, in 1894.
The Chinese name for monarch butterflies can be translated as,”the butterfly with black veins and golden spots” and precisely describes the external physical characteristics of this butterfly: A beautiful pattern on the is formed by the intense color contrast of black veins and orange wing spots formed at the intersection of the dark vessels. On the hind wings there are 10 wing spots each and 6 on each forewing. The main color tone of the forewings is tawny-orange to orange with black margins, and in the margins are two series of small white spots. Monarch forewings also have a few orange spots near the tips. Wing undersides are singular, but the tips of the forewings and hind wings are yellow-brown instead of tawny-orange and the white spots are larger. The male has a black spot of anthropological scales on the part of each hind ruing to send out pheromones, and its veins are brownish black in color. Tile males are slightly larger than females, but their black veins are narrower.
Range and Habitat
Monarch butterflies are mainly found across the southern part of North America and the northern part of South America. Occasionally they enter the western part of Europe via American ships and suitable wind direction and climate. They are also found in Bermuda, Hawaii, the Solomon Islands, New Zealand, Australia, New Guinea] Sri Lanka and India. Monarch butterflies can live in various kinds of habitats, like farms, grasslands, prairies, cities] suburban parks, forests] and roadsides. Milkweed plants are their main food source. They pass the winter in coniferous forest groves. The larvae of monarch butterflies eat the milkweed that contains cardenolides, a type of steroid, to discourage predators from eating them. The bright colors of the law and adult butterflies also as a
warning signal to potential predators.
A monarch butterfly typically lives only2to 6 weeks. Thus it must breed four times a year to perpetuate its species. The first generation is born in the spring, and the fourth (also the last) is bore at the end of summer. The adults of the first generation die immediately after position. The second generation is born, following the cycle until the fourth generation. In particular, the adults of the fourth generation are different from their predecessors. They do not opposite as the formers, but enter a diaphanous period, a special physiological stage which can last for months or longer, so as to prolong the lifespan to finish the migration to the south and wintering in Mexico until March of the following year. The extra lifetime they experience totals nearly half a year, which about equals the combination of all the lifespans of the former three generations.
Monarch butterflies in the wintering ground wait until the February or March of the next year to mate just before the migration back to the north for mating, they migrate north and east to find a suitable ovipositing ground. In March or April, they find milkweed plants for oviposit. It takes four days for the larva to release from the egg. After two weeks of feeding on milkweed plants, they become adults and start to search for a suitable place to begin the process of metamorphosis.
Monarch butterflies carry out a long-distance migration at a certain time period each year, much like bird. There are two main reasons for this epic migration. One reason is climate. The butterflies first migrate from north to south because they cannot survive in the cold continental climate of the northern and middle parts of North America in winter. The second reason is food scarcity Monarchs migrate back from south to north because there is no suitable food for the larva in their wintering ground. Therefore, the first generation bred in spring must be born in the north where their food grows.
In spring after macing season, adult monarch butterflies travel to the south of the United States to lay eggs and die shortly thereafter. The freshly hatched monarchs continue to migrate to the north and arrive in North America where their the first cycle and generation of monarch butterflies once lived. In autumn that same year, monarch in North America migrate to the south in large groups, a process which continues unto the first host. Sadly however, during the whole north-south-north migration of monarch, no single individual ever finishes one complete migration circuit. Even so, this amazing butterfly a tiny creature weighing less than a piece of paper, continues the life cycle by flying along its ancestral routes year after year and arriving precisely at their wintering ground in North America. In autumn the fourth generation of monarch butterflies migrates to their wintering ground in the south, a place they have never been before. Thousands of kilometers away several generations removed, it remains an unsolved mystery of how they can always return to the same wintering ground.Presumably a monarch’s migration seems to be inherited characteristic, dependent on the position of the sun, and following some sort of biological signals inside the tentacles for discerning position and navigation. New research indicates that monarch butterflies can use the earth magnetic held to navigate. There is cryptochrome in the tentacles, which is a kind of phototeceptor protein sensitive to violet-blue. If there are any violet or blue rays, the cryptochrome will as a chemical compass to advise the butterfly if the route fits d1e earth’s magnetic held or no.
Coniferous Forest ecosystems are a key factor for the survival of monarch butterflies in winter. The unique climate promotes monarch survival rates, supporting them unto reverse migration the spring by reducing the loss of water and ensuring the storage of energy.With an increasing human population and larger demands for biological resources, the worlds forests decease day by day including across Mexico. Deforestation strips away the monarch’s natural wintering ground as the conifer forests they inhabit are declining. What is more, manmade Forest fires have destroyed weed plants in recent years and humans also pull out the weed to keep garden spaces looking tide.All these human behaviors reduce the food sources for monarch butterflies.
Sharp climate change in the littering grounds is a frequent reason for large-scale death among monarch butterfly populations. Though Mexico is located in the tropical zone, its temperature in winter is quite log especially at the tops of high-altitude mountains. Monarchs have no intrinsic heat preservation meadows so the best they can do is to gather in clumps to keep warm in cold weather. At the end of January 2002, heavy rains drenched Rosario and SieTa, the two largest wintering grounds of monarch butterflies in Michoacan state. It was the heaviest on record in 25 years. After the heavy rain, temperatures fell below zero, causing the death of millions of monarch butterflies. To protect those beautiful creatures, Mexico’s government built S nature reserves with a total area of 16,000 hectares in Michoacan state and Mexico state in 1980. The whole region was expanded to 56,200 hectares in 2001. In addition to the efforts made by the Mexican government, several Mexican and international non-governmental organizations played important roles in monarch protection.
By establishing nature reserves] the government hopes to change the current situation of deceasing habitats, helping the monarch butterflies to safely survive the winters there every year. By focusing on ecological tourism, the goal of reaching a harmonious unification of conservation and utilization of nature may become a reality Monarch migration, one of the most spectacular natural scenes in Mexico, has attracted visitors Gram all over the world to view the nature as it unfolds.