Monarch Butterfly Characteristics - Research Paper Example

?Introduction Monarch butterflies are a species that keeps many mysteries in its life about which humans marvel. They are very beautiful with bright orange, black and white shades on its wings and considered by many as the king of butterflies (Frost, 10). The large orange wings are veined and outlined in black, with white dots decorating the black outer edges of each wing. The scientific name of this butterfly is Danaus plexippus (US Forest Service, 2). The species, comes under the family, Danaidae and genus, Dannaus (Garber, 76). All the members of this genus, including Monarch butterflies feed on alkaloid-rich plants (Capinera, 2460). Butterflies and moths belong to the order, Lepidoptera (Capinera, 628). The special characteristics of this order are the presence of a “complete, holometabolous life cycle, with separate egg, larva, pupa, and adult stages” (Capinera, 631). And this is why butterflies are classified under this order. A Monarch butterfly has also a similar wing span which comes to “3.5 to 4 inches” (Garber, 76). Another common feature of the members of Lepidoptera order is that all of them have “four wings and also scales covering at leats some body parts (Capinera, 631). In Monarch butterflies, the scales are seen “as a patch near the central veins of the hindwings” (Capinera, 631). There are two subspecies in Monarch butterfly (Oberhauser and Solensky, 1). The species, Danaus plexippus plexippus, is found in “Southern Canada, the USA, Mexico, most Caribbean Islands, Central America and northern South America” (Oberhauser and Solensky, 1). The second subspecies, Danaus plexippus erippus is seen in “Peru, Bolivia, Chile, Argentina, Uruguay, Paraguay and Eastern Brazil” (Oberhauser and Solensky, 1). Monarch butterflies are cold-blooded insects (Learner.org). So they are comfortable in cool climates as in such an atmosphere, they do not need to spend much energy (Learner.org). It can be seen that “the body of the caterpillar will be covered with nine brown rings aside from black head and it features three pairs of ‘true’ legs with claws attached and five pairs of prolegs that extend backwards” (Monarch-Butterfly.com). To differentiate a female monarch butterfly from a male, one has to look for a simple identification mark -“the male monarchs have a black spot on each of the hind wings over a vein. The female monarch butterfly does not have this spot” (Monarch-Butterfly.com). In one year, four generations of monarch butterflies complete their life cycle (Monarch-Butterfly.com). The life cycle of a monarch butterfly on the other hand includes four stages, namely, the egg, the larvae, the pupa and the butterfly (Monarch-Butterfly.com). The annual life cycle of this majestic insect can be considered to begin in the months of February and March when they mate (Monarch-Butterfly.com). After mating, the butterflies migrate to the Northern and Eastern parts of North America and lay their eggs there in the months of March and April (Monarch-Butterfly.com). It is on the milkweed plant that the Monarch butterflies lay their white eggs (Monarch-Butterfly.com). The eggs will be seen on the undersides of milkweed leaves, usually near the top of the plant. Each female butterfly lay “several hundred eggs” and the eggs hatch in four days (Monarch-Butterfly.com). There are many invertebrate predators that feed on Monarch eggs and larvae like, red velvet spider mite (Oberhauser and Solensky, 6). The caterpillar is herbivore and feeds only on milkweed leaves for two weeks and then attach to a small stem or a leaf of the plant and starts metamorphosing into the pupa stage (Monarch-Butterfly.com). Because of the insistence of the caterpillars on eating only the milkweeds, Monarch butterflies gained another name, the “milkweed butterfly” (Monarch-Butterfly.com). The caterpillars are only “about 0.1 inches long” weighing 0.55 grams (Monarch-Butterfly.com). Caterpillars have alternating bands of yellow, white, and black, on their body with a black stripe between pairs of white (Oberhauser and Solensky, 5). They go through five instars, growing from 2 mm to nearly 25 mm in about 15 days (Oberhauser and Solensky, 5). They are protected naturally from predators like frogs and birds by the poison that goes into their body from the milkweed leaves (Monarch-Butterfly.com). This poison remains in the body of the adult butterfly as well (Monarch-Butterfly.com). But extreme weather and pesticides can kill the larvae (Oberhauser and Solensky, 6). It is the silk secretion that comes out of the body of the caterpillar that becomes the weaving thread for the outer cover of the pupa (Monarch-Butterfly.com). The pupa stage lasts for 10 days (Monarch-Butterfly.com). The pupa weighs “about 1.5 gms…and is roughly two inches long” (Monarch-Butterfly.com). The pupa or chrysalis is “green with gold spots” (Frost, 9). Once the butterfly comes out, it has only two to six weeks to look ahead for, as it is the average life span of a Monarch butterfly (Monarch-Butterfly.com). But nature would ensure that the butterflies mate and lay eggs before they die (Monarch-Butterfly.com). Adult monarch butterflies feed mainly on the nectar of flowers (Monarch-Butterfly.com). But they are also found to consume water and juice from the fruits (Monarch-Butterfly.com). The feeding organ of the butterfly is also unique. It is a small pipe-like structure called proboscis, “which is coiled under its head most of the time is what an adult monarch butterfly uses to suck up all of the nectar from plants” (Monarch-Butterfly.com). With this feeding organ, butterflies are able to consume liquid or juicy food items like nectar and water (Monarch-Butterfly.com). Come May-June, these eggs would hatch and the second-generation caterpillars come out into the world (Monarch-Butterfly.com). Once they also complete their life cycle, the third generation emerges in July-August (Monarch-Butterfly.com). But the forth generation of Monarch butterflies is a class apart. Their mother eggs hatch in September-October but the adult butterflies of this generation have been taught by nature to migrate to warmer regions of the world so that they can survive the winter of their native place (Monarch-Butterfly.com). This migration contributes to their longevity and they get a boon of life for another four to six weeks (Monarch-Butterfly.com). Usually from US, these fourth generation voyagers are found to travel to Mexico and California (Monarch-Butterfly.com). The summer-born Monarch butterflies are found to mate after 3-8 days from their coming out of the pupa (Oberhauser and Solensky, 7). The butterfly generation that overwinters lay eggs only in Spring though they mate even before the Spring (Oberhauser and Solensky, 7). It has been observed that the “ability of male monarchs to force unwilling females to copulate makes them unique among the Lepidoptera” (Oberhauser and Solensky, 7). Females usually mate with more than one male but the eggs will be fertilized by the last partner (Oberhauser and Solensky, 8). While mating, the male and female stay “paired for several hours” (Oberhauser and Solensky, 8). Migration The wintertime migration of Monarch butterflies traces a path that begins in the US and ends in Mexico and Southern parts of California (Monarch-Butterfly.com). It is the cold in the atmosphere that determines the time schedule of migration (Monarch-Butterfly.com). But usually, it has been observed that the migration starts in October (Monarch-Butterfly.com). In US, the natural home to Monarch butterflies is the New England-Great Lakes area, and the canyons of the eastern Rocky Mountains (Monarch-Butterfly.com). It is the Monarch butterflies that live in the eastern side of the Rocky Mountains that usually migrate to Mexico (Monarch-Butterfly.com). Their favorite resting place in Mexico is the oyamel fir trees of the forests in the state of Michoacan in central Mexico (Monarch-Butterfly.com). Once they settle down, they pass into a stage of hibernation (Monarch-Butterfly.com). It is the microclimate of the oyamel forests that help the butterflies to survive the warm days and very cold nights here (Learner.org). Scientists are still studying the nuances of this microclimate. The Monarch butterflies from the western side of the Rocky Mountains have been found to hibernate on eucalyptus trees in Pacific Grove in California (Monarch-Butterfly.com). It has been discovered that there are only 12 locations on the whole earth that become winter destinations for these butterflies and all these 12 locations are mountain-tops (Learner.org). These mountain-tips are found to be at least 10,000 ft high (Learner.org). Some of the butterfly sanctuaries are, Sierra Chincua, El. Rosario and Chivati-Huacal (Learner.org). Taken together, the whole area where butterflies arrive is a very small piece of land with a width of only 73 miles (Learner.org). While migrating, a Monarch can cover 80 miles a day at a speed of up to 11 miles per hour (Migration and Dispersal of Insects by Flight, 534). One very interesting fact is that every year, though the migrant butterfly generation changes, the butterfly swarms (having tens of millions as members in a group) that arrive at their destination are found to hibernate on the very same trees that were used by their predecessors (Monarch-Butterfly.com). Also they travel in daytime alone and at nighttime roost on pine, fir and cedar trees, which are en-route (US Forest Service, 5). When they have to cross water bodies, they wait on the shore for a breeze to come and carry them ahead (US Forest Service, 6). And another amazing fact is that these migratory butterflies travel around 2,500 miles to reach a place where there is warmth in the winter (Monarch-Butterfly.com). On a single branch of a tree on which these butterflies hibernate, there can be even 15,000 butterflies hanging (Learner.org). Monarchs cluster together in this way because it helps them to stay warm (US Forest Service, 4). The migration is supposed to have two logical notions of nature behind them. One is that the winter in US will be so severe that if they stay, they would freeze to death (Monarch-Butterfly.com). Second, the plants, which the butterfly larvae keep an appetite for, do not grow in plenty in winter (Monarch-Butterfly.com). Come spring, these feeder plants will abound in US territories and it is the time for the Monarch butterflies to come home back (Monarch-Butterfly.com). This homecoming is also made necessary by the lack of larval feeder-plants in the warmer regions (Monarch-Butterfly.com). The migration of Monarch butterflies to survive the winters is described using the term overwintering (Monarch-Butterfly.com). The butterflies arrive in their winter destination with “fat (lipids) stored” inside their abdominal muscles (Learner.org). During the winter period, they eat only very little and survive mostly on the body fat (Learner.org). Too much cold and too much warmth can kill a Monarch butterfly. But inside a forest, there will always be a balancing between extreme climates and hence they are safer in forests though the overnight temperatures in the Mexican forests may sometimes drop below freezing point (Learner.org). Another interesting fact is that even if there is occasional snowing, these butterflies can survive buried under the snow “for more than a week” (Learner.org). Monarchs have to face many predators in the Mexican forests. The poison inside their body is their only shield of protection. It is “stored in the butterfly’s cuticle (skin)” (Learner.org). But mice, orioles and Grosbeaks eat these butterflies (Learner.org). Mice can eat only butterflies, which are fallen to the ground for some or other reason (Learner.org). Though there are four specie of mouse in this part of Mexican forests, only the black-eared mouse is found to feed heavily on Monarch butterflies and they are immune to the poison (Learner.org). The orioles avoid eating the cuticle by cutting it open using its pointed beak and thus survive the poison (Learner.org). Also, orioles schedule their time of feeding in the morning and the evening when the butterflies are not able to fly because of the extreme cold (Learner.org). For flying well, Monarchs need above 20C temperature (Learner.org). Grosbeaks adopt a different strategy. They eat the entire butterfly body but choose to eat the males than females (Learner.org). This is because the body of males contains less poison (Learner.org). But the monarch butterflies can sometimes avoid predators by way of the common coloration between their closed wings and the tree trunks and branches somewhat synchronizes into a camouflage (Learner.org). The bright, contrasting colors of the caterpillar's skin and the butterfly's wings also advertise their un-palatability to potential predators (US Forest Service, 8). Also it is seen that Monarch colonies change their locations many times in the Mexican forests until their journey back home (Learner.org). This shifting is associated with the minute variations in the climate (Learner.org). It was a Canadian biologist named Dr. Fred Urquhart, who discovered the migratory destination of Monarch butterflies (Learner.org). He constituted a team of volunteers and they tagged several thousands of monarch butterflies just before the migratory season started (Learner.org). In this way it was found out that the destination of the migratimg butterflies was a small region in Mexico (Learner.org). National Geographic Magazine first announced this discovery in its 1976 issue (Learner.org). Tracking Realizing the vulnerability of Monarch butterflies in a modern urbanized world created by humans, North American conservationists have started a Monarch Butterfly Migration Tracking Project (Learner.org). It is a big team of students and scientists in North America that undertake this project (Learner.org). This team will prepare a probability map of the path that butterflies would take for their migration (Learner.org). There are mainly two purposes for this journey. One is to study the unknown aspects of the migration and the second objective is to create an awareness among the people who inhabit the migratory route and destination about how important it is to protect the migrating butterflies and how could they be helped (Learner.org). They also try to find out what could be the possible threats that this species face during migration (Learner.org). Once the trackers reach the hibernating destinations in the forests, they stop talking and only whisper to each other (Learner.org). This is to minimize the disturbance caused by human presence. Usually the butterfly swarms that cover like an extra-skin on the tree trunks remain motionless but once in a while, the groups just explode into a tantrum of hurried flying just like “fireworks” (Learner.org). This is one of the most beautiful and rare sight that a tracker can have. The trackers first mark the edges of each colony that they are studying using flagging tape (Learner.org). For this, the scientists locate the trees that have butterflies, which can be considered part of one colony (Learner.org). The next step is to walk around and measure the distances between the trees that inhabit a single colony (Learner.org). This is to calculate the area inhabited by each colony (Learner.org). It is tentatively calculated from such measurements that there could be 10 to 50 million monarch butterflies in one acre of a hibernating forest (Learner.org). The scientists also use the “Mark, Release, Recapture” method to count the butterflies (Learner.org). In this method, the scientists have to visit a single population two times (Learner.org). In the first visit, a few butterflies are caught and marked (Learner.org). In the second visit, the scientist recaptures as much marked butterflies as possible and from the number of marked butterflies recaptured, the total number of the population is calculated using the equation, “a/b = c/d” (Learner.org). Here, ‘a’ is individuals marked on first visit, ‘b’ is total population size, ‘c’ is marked individuals recaptured on second visit and ‘d’ is total individuals captured on second visit (Learner.org). The US Forest Service International Programs, the Trilateral Monarch Butterfly Sister Protected Area Network, North American Monarch Conservation Plan, Monarch Model Forest, etc. are some major projects and organizations working for conserving this species (US Forest Service, 10-11). The deforestation that is going on in the Mexican and Californian forests is found to have an impact on the migrating Monarch butterflies, which in turn may even endanger the species by disturbing their reproductive cycle (Monarch-Butterfly.com). When the trees on which they regularly hibernate are gone, these butterflies may get confused and their return journey after the winter will also become uncertain. Also, when milkweed plants are destroyed by the ongoing urbanization in North America, the Monarch caterpillars will have nothing to eat. This may even lead to the wiping out of this species. In the recent wild fires, thousands of milkweed plants were destroyed (Monarch-Butterfly.com). Also people have a tendency to destroy the milkweeds in their property because it has a not so good smell and also because it is a weed in the eyes of humans (Monarch-Butterfly.com). Another problem is that “the oyamel forest ecosystem is Mexico's most endangered forest-type. Only 2% of the original forest remains” (Learner.org). Another alarming issue has been that it is found out, the pollen of Bt corn that gets deposited on milkweed leaves and get eaten by the Monarch larvae, increase their mortality rates (Losey, Rayor and and Carter, 214). In view of all these hazards, conservationists are trying their best to preserve the forests as well as to protect milkweed plants (Monarch-Butterfly.com). In 1986, the Mexican government, in view of the endangered nature of these butterflies and in recognition of their ecological importance, declared the region that hosts migratory destinations as Monarch Butterfly Biosphere Reserve (US Forest Service, 4). Works Cited Capinera, John.L. Encyclopedia of Entomology, Berlin: Springer, 2008. Print. Frost, Helen, Monarch Butterflies, Minnesota: Capstone Press, 2006. Print. Garber, Steven.D. The Urban Naturalist, New York: Courier Dover Publications, 1998. Print. Learner.org. Journey North’s Monarch Butterfly Tracking Project, n.d. web. 20 April 2011. http://www.learner.org/jnorth/monarch/ Losey, John.E., Rayor, Linda.S. and Carter, Maureen.E. Transgenic Pollen Harms Monarch Larvae, Nature, Vol.399, 20 May 1999. pp. 214-215. Print. Migration and Dispersal of Insects by Flight, London: Taylor & Francis, n.d. Print. Monarch-Butterfly.com. The King of Butterflies- The Monarch Butterfly, n.d. web. 19 April 2011. http://www.monarch-butterfly.com/ Oberhauser, K.S. and Solensky, M.J. Monarch Butterfly Ecology, ECOLOGY.INFO 28, 2006. Print. United States Forest Service, Monarch Butterfly: North America's Migrating Insect, Washington: U.S. Department of Agriculture, Forest Service, 2008. Read More