Dangers Of Transfers Of Monarch Butterflies example essay topic

The monarch butterfly, as known as Danaus, is often called the milkweed butterfly because its larvae eat the milkweed plant. They are also sometimes called 'royalty butterflies' because their family name comes from the daughter of Danaus, ruler of Argos. There are many other interesting facts about this butterfly including its anatomy and life cycle, where the butterfly lies on the food chain, the migration from Canada to Mexico, why the butterfly is being threatened, and lastly, what is being done to help the butterfly. The anatomy of the monarch starts with it coloring. The monarch butterfly is bright orange with a white spots in a black margin around the edges.

The veins on the wings are also black. The caterpillar is ringed with yellow, black, and white on each segment and has a pair of black fleshy tubercles at each end (Emmel, 1999). Monarchs smell with their antennae while they taste with their feet (Wexler, 1994). While the male monarchs have scent scales on their wings and 'hair pencils' on their abdomens which secrete a scent (Emmel, 1999). The male scent is used during mating. The copulation of a male and female monarch can last from thirty to sixty minutes which is about average for most butterflies (Emmel, 1999).

The life cycle starts as larva or caterpillar. First, the monarch lays the eggs on the milkweed plants. Next, the egg hatch into a caterpillar. The caterpillar then eats the milkweed plants until they are large enough to pupate (Emmel, 1999). Then, the caterpillar attaches a pad of silk to a stem of a milkweed plant so it can hang while it transform into a butterfly. Next, the caterpillar sheds it larval skin to reveal the chrysalis inside (Emmel, 1999).

After it shed its skin, the pupa hardens and the chrysalis earns it name by glowing in the sun. As the pupa stage comes to an end, the butterfly can be seen through its pupa shell. The monarch emerges by splitting the pupa along the length of it proboscis (Emmel, 1999). First the legs emerge. Then the fluid fill body pumps its fluid into the veins of the wings while the body shrinks to normal size.

Finally, the butterfly hangs from the pupa about two hours while the wings dry (Emmel, 1999). Monarchs do not have many predators expect for man. The monarch's trick to not being eating it two hold. First, the coloring of the monarch mimics that of a wasp or a bee which makes predators think twice before trying to eat them. Second, the milkweed plant in which the caterpillar eats has toxins which make the wings of the butterfly distasteful to predators. The monarch butterfly drinks nectar while the caterpillar eats the milkweed.

The monarch favorite food here in Florida is Asclepius's sp. or milkweed (Wexler, 1994). The migrating of monarch is because of the harsh conditions on the northern US. They move south from areas of southern Canada and most of the US to a few sites in Mexico (Grzimek's, 2003). They migrate itself usually takes three to four generations of monarchs (Clattenburg, 2004).

Scientists do not know why they migrate, but there are different theories. The first theory is the change of light in fall (Clattenburg, 2004). While others scientists claim the monarchs have a chemical in their bodies in which they are attracted to Mexico where the congregate in certain trees (Clattenburg, 2004). The latter does not explain why monarchs stay in Southern Florida as permanent residents (Emmel, 1999). Three different things are endangering the monarch butterfly. First, is the deforestation of Mexico.

Through illegal logging of the forests and the thinning of the canopy the monarchs are left vulnerable to the elements including frost and freezing rain (Wexler, 2004). Second, is a genetically engineered corn. The corn is engineered to be insect resistant which when the milkweed plant grows on the edges of the fields, the studies have shown the monarchs are being killed (Stix, 1999). Lastly, is the inter population of the monarch butterfly. The monarchs live on both sides of the Rocky Mountain Range.

Some scientist have taken the monarch west of the Rockies and mixed them with the monarchs east of the Rockies and vice versa. There are two arguments against this inter population. First, transferred butterflies can bring infectious and lethal diseases into new populations. Second, transfers may hurt or confuse our understanding of the biology of the monarch. With all these different ways man is endangering the monarch butterfly; it makes us wonder what can be done about it (Brower, et al, 1995). In Mexico, a man by the name of Jose Luis Alvarez, is working to teach the local on how make better use of their land (Clattenburg, 2004).

In the past ten years, he claims he has plant over a million new trees to help with the deforestation and the demise of the monarch (Clattenburg, 2004). In the US, the corn industry is hurting by the genetic engineered corn. It cannot sell the corn to European markets so the engineered corn is not the premium corn on the market. With the help of Alvarez, Mexico will still be the place of the monarchs winter home, and the human race objecting to engineered food, the monarch may still have a fighting chance for survival. With all these interesting facts about the monarch, the anatomy, life cycle, milkweed plant, migration, the endangerment, and the help of Alvarez, it is a wondering why more people are not doing more to help this national treasure. Literature Cited Brower, Lincoln P., Fink, Linda S., and van Zandt Brower, Andrew.

1995. On the dangers of transfers of monarch butterflies. Bio Science, 45: 540-4 Clattenburg, Will, 2004. A Mission for Monarchs.

American Forests, 110/2: 32-7 Grzimek's Animal Life Encyclopedia, 2nd edition. Volume 3, Insects, edited by Michael Hutchins, Arthur V. Evans, Rosser W. Garrison, and Neil Sch lager. Farmington Hills, MI: Gale Group, 2003. Stix, Gary, 1999. The butterfly effect. Scientific American, 281/2: 28-9 Wexler, Mark, 1994.

How to feed a visiting monarch. National Wildlife, 32: 14-21.