MONARCH BUTTERFLY – LA MARIPOSA MONARCA
Monarch butterfly anatomy consists of the following: Head with a set of tubercles and compound eyes; attached to the thorax are two sets of wings, fore wings, hind wings and six legs; and the butterfly has an abdomen.
Look at the hind wings and you will see two small black pheromone glands. These are called hairpencils. The male butterfly wafts a scent of pheromones over the tubercles of a mother butterfly. Cornell scientists have identified the pheromone as danaidone. The alluring scent and a powdery substance can attach to a female’s antennae and woo a mother butterfly.
Adult monarchs do not fly at night or when it is too hot. Butterflies will seek out shade to rest in. The monarchs cannot fly when it is below 55 degrees Fahrenheit. The butterfly starts to fly at approximately 10 a.m. when the sun begins to warm them; they are most active between 10 a.m. to 2 p.m. Did you know the monarch butterfly can fly approximately 50 miles a day?
THE EGG – HUEVECILLO
The male and female monarch butterfly will fly from Mexico to Texas. There they will mate and shortly thereafter die. The mother butterfly urgently needs to find milkweed to deposit her eggs on. This last act will insure the next generation of monarch butterflies. There are four generations that wind their way towards Canada. The fifth generation is the one that lives the longest and returns to Mexico in early fall. How does the butterfly know where milkweed grows?
The butterfly flits over a field or garden looking for milkweed. Watch the flight pattern and you may see a mother butterfly looking for a host plant. Plants have ultraviolet patterns on their leaves and flower petals making them visible to pollinators such as the monarch butterfly. Humans can’t see this but a butterfly can. A monarch uses a combination of visual and chemical cues to find milkweed.
Once a mother butterfly lands on milkweed, she uses sensory organs in her feet and head to make sure it is milkweed. A monarch may even drum on a milkweed leaf with her forefeet to be certain. The forefeet are located close to the head.
Notice that there are three eggs on the milkweed plant in the illustration. The mother butterfly carries approximately 200 eggs in her stomach. She touches the abdomen to the underside of a leaf and deposits an egg. The mother usually deposits only one egg per plant. There is a reason for this. It is probable that the first caterpillar to emerge from an egg will scout for other eggs. A caterpillar is able to defend its own food territory when there is no competition. Eggs have protein. Sometimes a mother butterfly is in a hurry and may deposit more than one egg on the same plant. This is known as egg dumping.
By depositing eggs on different milkweed plants, eggs have a better chance of survival if something goes wrong. There are many risks to milkweed including: Some plants may not be as hardy as others; a storm could destroy a plant; milkweed might be removed because a gardener thinks it is a weed; a land developer could clear cut a large track of land removing all native plants; farmers may plant monoculture crops, genetically engineered crops and may spray crops with pesticides.
There is a loss of approximately 3,000 acres of farmland each year to development. Roadside crews may use herbicides (ER-beh-syds) which poison milkweed, a plant that grows along roadways, one of the major corridors of butterflies. If there is no milkweed along the migration trail, there will be no monarch butterfly migration. This is why it is so important to let milkweed grow.