Monarch Butterflies in the Siskiyou Mountains
|Graphic by Journey North
Population of monarchs at the overwintering grounds in Mexico
|Monarch population chart for monarchs living west of the continental divide that overwinter in California|
In May, 2014 both Jackson and Josephine Counties in Oregon passed ballot initiatives that will ban the planting of GMO crops. The landslide victory in Jackson County shows that most people don't want GMO crops planted in Jackson County. The measure passed 65.9% Yes to 34.1% No. In Josephine County the results were 58% to 41% These two measures will greatly improve the chances of monarch recovery in the Siskiyou Mountains.
- Loss of milkweed
- Logging of overwintering grounds in Mexico
- Climate change
- GMO crops
- Pesticide use
- Coastal development of overwintering grounds in California
butterflies fluttering around two separate showy milkweed (Asclepias speciosa)
patches that my wife, Suzie, planted nine years ago. One patch is in our
vegetable garden and the other in a native rock garden on the side of the road.
Previously we had only seen one tattered monarch scoping out our patches, so
this was a hopeful sign. When Suzie got home from work that day I told her what
I saw and she immediately inspected for eggs. Sure enough, there were about
fifty eggs combined on both the patches of milkweed. Research has shown
that a female monarch typically lays about 700 eggs in its lifespan, so this
was not a huge number of eggs.
|Monarch caterpillar eggs on milkweed|
|Monarch caterpillar eggs are very small|
|Monarch caterpillars are tiny and vulnerable when they first emerge.|
to hatch and an estimated 15-20 tiny, little caterpillars emerged. They were
hard to spot because they hid within the plants and it was hard to keep track
of them and know for certain how many there were.
|When small the caterpillars stayed within flower buds.|
|The caterpillars eat the milkweed plant and grow bigger.|
|As they get bigger they are easier to spot.|
|Sometimes they eat the flower buds.|
|Some small caterpillars died of mysterious causes.|
of caterpillars disappeared, but those that remained got bigger and fatter.
Monarchs have natural predators, parasitoids, and parasites that can harm
monarch eggs, larvae, pupae, and adults. It’s a tough world for monarchs in
their natural setting, and human impacts to habitat just compound the threats.
grow and need to shed its skin five times. Each skin is called an instar. The
stages of a caterpillar’s life are referred to as the first instar, second
instar, third instar, fourth instar, and the final fifth instar. We observed
the caterpillars eating the skin after it was shed, as if it was a source of
|Hanging out on milkweed|
|Munching on milkweed|
|The caterpillars rested under the leaves|
|5th instar caterpillar|
|Monarch caterpillar hanging in “J” shape on June 23, 2014.
The caterpillar has attached itself
with a cremaster and hangs in a “J” shape as it prepares to
shed its old larval skin and begin the formation of the chrysalis.
|Monarch in a chrysalis formed on June 24, 2014.
scientific name for the monarch butterfly is Danaus
plexippus, a Greek term meaning “sleepy
transformation.” This reflects the species’ metamorphosis.
|Monarch on showy milkweed in May, 2014|
butterfly the monarch will eat, mate and lay eggs if it is a female. They will
search out and find whatever milkweed they can. Monarchs will use any plant in
the genus Asclepias, even cultivars of the native species. The last
generation in the migration will then head south to the California coast to
overwinter and start the cycle anew as has happened for millennia.
Monarchs fall to the ground while mating.
|Monarch butterflies cluster together for warmth as
they overwinter at the Pismo Beach Monarch Butterfly Grove in
California. This colony is one of the largest in the United States.
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