DISCOVERY FILE: Monarch Butterfly
Biology and Migration
The Monarch butterfly is a pollinator (an
insect that carries pollen from one flower
to another). It has four life stages: the
egg, the larva (caterpillar), the pupa
(resting stage or chrysalis) and the adult
butterfly.
Adult Monarch butterflies lay eggs in
March and April on milkweed plants. The
Ryan E. Poplin [CC-BY-SAeggs hatch after about 7-10 days. Dry
2.0], via Wikimedia Commons
conditions and temperatures above 95F
(35C) can be deadly to the development of the butterfly and
to milkweed plants as well. When the eggs do hatch, the
caterpillars will feed on the milkweed plants.
Milkweed contains toxins (poisons) that are harmless to the
Monarch. However, these toxins remain in the adult Monarch’s
body making poisonous to its predators. An adult Monarch will
feed on nectar from a variety of flowers including milkweeds.
In spring, summer and early fall Monarchs can be found
wherever there are milkweeds. Monarchs cannot survive
freezing temperatures and neither can milkweed. So in the
winter, Monarchs from the east of the Rocky Mountains
overwinter (spend the winter) in
the Oyamel fir forests in
central Mexico.
An adult Monarch typically lives
four to five weeks, but each
autumn a special group emerges.
These special butterflies will
Derek Ramsey (Ram-Man) (Own work (Own
live seven to eight months, and
Picture)) [GFDL 1.2], via Wikimedia Commons
they are born to make an
incredible journey. When the days begin to get shorter and the
air gets colder, the butterflies sense it is time to migrate (to
move or travel to another area or region, sometimes at regular
or annual times).
Fun Facts about
the Monarch
butterfly:
The scientific name
of the Monarch
butterfly is Danaus
plexippus, which
means “sleepy
transformation”,
referring to its
amazing life cycle.
A Monarch butterfly
can travel up to
3,000 miles to reach
its wintering ground
in Mexico.
Scientists track the
Monarch migration
by putting a sticky
tag on the wings of
the butterflies.
A Monarch
caterpillar will
increase in size
3,000 times from
the day it hatches to
when it becomes a
chrysalis.
A Monarch’s bright
orange color tells
predators “Don’t eat
me, I am poisonous!”
DISCOVERY FILE: Monarch Butterfly
Early fall, as many as 100 million monarch butterflies migrate from northern parts of North
America to California and Mexico. Monarchs can fly up to 3,000 miles (4,500 km) just to reach
their overwintering place. It may take monarchs up to two months to their winter place. This
place is cool and moist. Monarchs will gather on trees forming clusters to stay warm. The
temperature ranges from 32F - 60F (0C - 16C). When warmer temperatures arrive in
March, this will signal the monarchs to begin the journey back north. The Monarchs that
overwintered in Mexico will make it about halfway to their summer habitats before they lay
their eggs and die. It will take about four more generations of their shorter-lived offspring to
complete the journey.
Environmental Science – Global Changes
Although the monarch butterfly is not on the endangered species list, their yearly migration is
considered an endangered event. Monarchs are in danger of losing their summer and winter
habitats. Summer habitats and milkweed are destroyed as more houses, roads and businesses
are built. In many places people use chemicals to kill milkweed. Winter habitats have been
damaged and lost as the land is logged (to cut down trees). Lastly, climate change has also been
threatening the monarch’s migration. Colder, wetter winters could be deadly to the butterfly
and hotter, drier summers could shift suitable habitats north. Unusual patterns of drought and
rainfall could have an effect on milkweed plants.
Conservation – How to Help
To help, people in many places are planting milkweed plants in their gardens, yards and
schoolyards. These plants provide places for Monarch butterflies to lay their eggs, food for
caterpillars and nectar for adults. Other flowers that are planted will also provide important
nectar for these butterflies.
Resources
BioKids
http://www.biokids.umich.edu/critters/Danaus_plexippus/
Monarch Watch
http://www.monarchwatch.org/
Journey North
http://www.learner.org/jnorth/tm/monarch/jr/KidsJourneyNorth.html
Exploring Nature Educational Resource
http://www.exploringnature.org/db/detail.php?dbID=32&detID=1209
National Geographic Kids
http://kids.nationalgeographic.com/kids/animals/creaturefeature/monarch-butterflies/