Monarch Butterfly (Danaus Plexippus)

Abstract

The monarch butterfly (Danaus plexippus) is an inhabitant of North and South America. However, they have spread to other parts of the world such as in South Pacific islands, Australia and New Zealand as well as other countries in central part of Africa. It is a brightly orange colored butterfly with black stripe markings and is beautiful to look at. It is a species of milkweed butterflies of the danaidae family. Two sub-species of the Monarch exist in the Western Hemisphere; Danaus plexippus plexipppus in South Canada, USA, Mexico, South and Central America and Danaus plexippus erippus of Peru, Chile, Paraguay, Argentina and Uruguay (Bonanno 67). The North American monarch butterfly is known for it’s incredible migration where individuals fly from their summer breeding grounds to overwintering habitat in central Mexico.

The Monarch cannot survive in cold weather hence the migration of as long as three thousand miles to reach warmer climates. It can be found in many habitats for instance fields, urban areas, gardens, trees and many others. Amazingly, each butterfly lives a year hence the migrations made by future generations every year. They lay three hundred to four hundred eggs and have incomplete metamorphosis and it’s larvae are specialized herbivores that consume only leaves of the milkweed family of plants. The milkweed provides them with a good and effective chemical defense against predators (Pringle 5).

Introduction

From its coloration, migration, lifecycle and even mating, this insect is extremely fascinating and interesting in every aspect of its life. There is a lot to learn about it, and the paper will give a good understanding of the monarchs’ classification, it’s lifecycle, it’s habitat, evasive features and migration.

Classification of the monarch butterfly can be traced back from kingdom Animalia. Under this kingdom, it is found under the phylum Arthoropoda and class Insecta. Under the class insecta, Danaus plexippus belongs to the order Lepidoptera which also consists of moths. This order consists of the family nymphalidae in which monarch butterfly is found under the subfamily Danainae, genus Danaus, and finally species plexippus. Monarch butterfly is also known as milkweed butterfly due to the fact that their larva feeds on the milkweed plant (Christensen 58).

Monarch butterfly (Danaus plexippu) is mainly found in North America also sometimes it is found in western Europe having flown to western or been transported to western Europe by American ships. It has also been found in other parts of the world such as Australia, India and New Zealand. Monarch butterfly feeds mainly on milkweed plants found in North America which thrive during the spring, summer and, autumn seasons (Bonanno 45). They migrate southwards during winter to the warmer Mexican and Californian highlands. However, the milkweed plants do not grow well in Mexico and southern California. Due to this forces monarch butterflies to fly to the North during spring in search of food.

Life cycle

Mating period for the migrating monarch population occurs in the spring, this just prior to migration from the overwintering sites. Their courtship is quite simple and dependents very little on chemical pheromones if compared to other species in it’s genus. Courtship is composed of two distinct stages that is the aerial phase and the other is known as the ground phase. the first phase if when the male takes down the female by nudgling after which copulation takes place at the ground phase. Here, the male and female remain attached for about 30 to 60 minutes. From the male, a spermatophore is transferred to the female along with sperm. The spermatophore plays the role of offering energy to the female insect during reproduction (Pringle 2).

Monarch butterflies have a very interesting life cycle. There are four different generations of monarch butterflies in approximately every twelve months. The first generation of monarch butterflies starts their life cycle between March and April when the fourth generation of butterflies hibernating in Mexico and south California emerge. This (fourth) generation of monarch butterflies migrates to the North which is beginning to get warmer. They lay their eggs on the leaves of milkweed plants. The egg when in a favorable environment takes about four days to hatch into wormlike larvae. The larvae are the most active and feed on the milkweed plant and grow (Christensen 7).

The larva is most vulnerable to predators because it does not have a hard covering like the pupa. The larval stage lasts for about two weeks when it has stored enough nutrients to take it through the pupa stage then it attaches itself by use of silk to a plant’s leaves or stem. It then transforms itself into pupa. Within the first ten days there seems to be nothing happening in the pupa but this is the most active stage when the caterpillar is being transformed into the beautiful butterfly (Bonanno 12). After at least ten days the butterfly emerges from the cocoon to enjoy the remaining two to six weeks remaining in it’s life cycle, and then they die.

The first generation lay their eggs between May and June which then goes through exactly the same life history as the first generation. When the second generation butterflies are sexually mature, they lay their eggs between July and August then it undergos the same stages as the first and second generations. Sexually mature third generation lay eggs that will develop to the fourth generation in September and august. The fourth generation has the same life history as the first, second, and third generations apart from the time when they become adults. Adult fourth generation butterflies migrate to Mexico and southern California to avoid winter in North America. They stay in these warmer climates for around seven months, and when the temperatures in the North have increased to a bearable limit (during spring in the North), they migrate to the North. They then lay their eggs which mark the start of the first generation and the cycle goes on and on (Pringle 56).

The monarch habitats include fields, meadows, prairie remnants, urban and suburban parks, gardens, trees, and roadsides. Interactions between the monarch and humans is majorly because of its beauty the best way that people catch sight of monarchs is by growing a butterfly gardens and grow specific milkweed species of plants. They have also been used in research, especially due to their migration patterns. Some people enjoy raising them for pleasure or for educational purposes. The migrating flocks have had people create sanctuaries at favorite wintering locations, and this has created areas of tourism attractions and used for revenue generation.

In education, numerous schools have undertaken to growing and attending to monarch butterflies along their lifecycle starting with the caterpillar form. They do this until they mature into adults and then left out to go to the wild (Bonanno 34). The Cape May Bird Observatory, have embarked on monarch identification tagging programs to track the butterflies and hence study their migration patterns, including the far they fly and where they fly to.

Monarch butterfly has various mechanisms of defending themselves against predators. These include methods like production of poisonous and foul tasting cardenolide aglycones. They also prove that they are unpalatable through their bright colors. Some group of birds like jays and orioles have also leaned to just feed selectively on some parts of these butterflies considering that those areas are of less harm as compared to other parts. Monarch butterfly is of great monumental value to humans. This has made most of the people plant a chosen species of milk weed so as to attract these wonderful creatures of the nature (Pringle 34). However, it has been determined to be the most existent form of the monarch butterfly is under threat as a result of some of deleterious human activities such as deforestation and air pollution. Therefore, there are plans underway to protect these species which is feared to be in the list of the extinct organisms in the near future.

Threats to the monarch butterfly are many among them being parasites like the tachinid flies and Lesperia-parasitized larvae. Also, the bacterium micrococcus flacidifex danai infects the larvae and can cause the “black death”. Another bacterium pseudomonas aeruginosa causes secondary infections in weakened butterflies hence considered as one of the most common cause of life of these insects. Besides bacteria, protozoans also attack the monarchs. It infects the subcutaneous tissue and propagates by spores that get formed during its pupal stage (Christensen 23).

Works Cited

Bonanno, SE. Jefferson County Alvar Megasite Conservation. New York: The Nature Conservancy, 1999.

Christensen, T. The ecology and control of Vincetoxicum spp. Rochester, NY: Wildflower, 1998.

Pringle, J. The spread of Vincetoxicum species in Ontario. Ontario: The Canadian Field Naturalist, 1998.