California’s Monarch Butterflies Tuesday December 1, 2015
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by Donna M. Walker

Protecting California’s Monarch Butterflies

Black and orange wings soar through the air for thousands of milesthen flutter gracefully towards the ground where they find rest in southern and central California trees.

Monarch Butterfly (Danaus plexippus) Male – Note the two black spots on the bottom wings.

Monarch Butterfly (Danaus plexippus) Male – Note the two black spots on the bottom wings.

If there is one insect, because of its beauty, that has captured the heart of Californians, it’s the Monarch Butterfly … unless of course, you happen to be an entomologist, then you probably find beauty in Jerusalem crickets – as only an entomologist could and would!

Migrating Monarchs

In southern California, once fall approaches, Monarch butterflies take refuge from their long journey south to the sheltering trees of San Diego, Orange, and Los Angeles Counties.

Map of Monarch Butterflies Fall Migration

Map of Monarch Butterflies Fall Migration

There are two populations of Monarch butterflies in North America that are separated by the Rocky Mountains; each with different migration patterns.

The Monarchs east of the Rockies migrate south to spend their winters in Mexico.

West of the Rockies, here in California, Monarchs migrate from Canada to the coast of central and southern California where they overwinter.

 

Wintering Monarchs

“Which way is up?” – Monarch caterpillar underneath a leaf.

“Which way is up?” – Monarch caterpillar underneath a leaf.

Overwintering Monarchs cling together in bunches among California trees. On sunny days, you may see them flying around neighborhoods, gathering nectar and water to drink.

As the weather warms, Monarch butterflies instinctively know it is time to migrate. Females fly north, seeking milkweed to lay their eggs.

A Monarch female can lay more than one egg, depending on how many times she mated!

Monarch Life Span

Overwintering Monarch butterflies can live 6 to 8 months, whereas spring and summer Monarchs live only 2 to 6 weeks.

Baby Monarchs born in the right season are programed to continue the “Great Migration” cycle from Canada to Southern California and back again.

It is estimated that it takes four generations of Monarch butterflies to make the entire round trip. Consider how amazing these delicate winged creatures are able to fly 50 to 100 miles a day!

Mating and Reproduction

Springtime is a flurry of mating activity; unlike drone bees that die after mating, both male and female Monarch butterflies get to mate several times.

Courtship starts when a male Monarch takes to the air to look for a willing female. If unwilling, sometimes the male forces her to the ground to copulate but since only 30% of copulation actually occurs, it appears that female Monarchs can get away if they want too.

Roosting Monarch Butterflies Overwintering

Roosting Monarch Butterflies Overwintering

During copulation, the Monarchs will remain attached for 30 – 60 minutes!

The more the female mates, the more eggs she lays. Sadly, mother Monarchs soon die after they’ve laid their eggs.

Eggs are laid on the underside of the milkweed plant; after they’ve hatched, baby Monarch larvae have a whole plant to feed upon. And feed they do! –

Take a look at this video of one of our technicians, Jay Strassner, helping release a new Monarch butterfly:

Monarch caterpillars have voracious appetites, eating 2700 times their initial body weight within a two week period!

After two weeks of gorging on milkweed, the Monarch caterpillar attaches itself to something sturdy like a tree branch or a fence; then it sheds its skin and develops a hard, outer green and gold-colored skin, called a chrysalis or pupa.

Female Monarch Butterflies lay eggs underneath leaves of the milkweed plant.

Female Monarch butterflies lay eggs underneath leaves of the milkweed plant.

During the next two weeks (10-14 days) a metamorphose occurs and the black and yellow striped caterpillar grows wings, changing into a beautiful orange and black Monarch butterfly.

Are Monarch Butterflies Ever Pests?

Adult butterflies are not pests but beautiful and beneficial garden insects.

These beautiful butterflies flutter about, gathering nectar, and help honeybees pollinate our plants … but what about butterfly baby larvae – caterpillars?

 
Monarch Butterfly’s Cycle of Life

Monarch Butterfly’s Cycle of Life

Monarch caterpillars feed only on milkweed, native to California and the rest of North America, which means – one doesn’t need to worry about caterpillars ruining ornamentals.

These baby butterfly larvae eat all parts of the milkweed plant; leaves, flowering buds, including the milky juice from the stems of the plant.

So, since they only feed on milkweed – Monarch baby butterfly caterpillar larvae (try to say that real fast!) for sure, are not pests.

Monarch Caterpillar – Beautiful yellow and black stripes make the baby larvae easy to identify.

Monarch Caterpillar – Beautiful yellow and black stripes make the baby larvae easy to identify.

Milkweed and Monarch Butterflies

Over the last several years, Monarch butterflies have decreased in numbers due to the loss of their milkweed habitat.

Development has taken over much of North America’s native landscapes where milkweed naturally grows .

In California, we have several different types of milkweed plants that Monarch butterflies rely on to lay their eggs (usually on the underside of a leaf) and for their larvae to feed on, once the eggs hatch.

California Narrowleaf Milkweed – What Monarch Caterpillars Eat

California Narrowleaf Milkweed

Milkweed is not just a food source for Monarch caterpillars but it actually protects both caterpillar and butterfly from predators.

Once caterpillars eat the milky juice of milkweed plants, they become terrible tasting to birds and other predators.

The toxins in milkweed protects Monarchs in both their caterpillar and adult stages of life.

Monarch Butterfly Imposters

Digital painting of a Queen Butterfly (Danaus gilippus) by Donna M. Walker

Digital painting of a Queen Butterfly (Danaus gilippus) by Donna M. Walker

Other butterflies, such as the Viceroy Butterfly, have developed markings on their wings to mimic a Monarch’s – a survival strategy that tricks its predators into thinking they are just as distasteful as a Monarch butterfly.

But Viceroy butterflies do not eat milkweed; also, a closer look reveals differences in wing patterns and the number and size of white dots.

Viceroy Butterfly (Limenitis archippus) Monarch Mimic

Viceroy Butterfly (Limenitis archippus) Monarch Mimic

However, there are milkweed eaters which predators will avoid besides the Monarch butterfly, such as the Queen Butterfly.

This butterfly is also orange and black and taste terrible to its predators.

The beautiful Queen butterfly is rightly named – she wears a solid cloak of orange with irregular white spots, like snowflakes, on her wings, and black trim, giving this butterfly a very “queenly” appearance.

Saving Monarch Butterflies

How can we help? One way to ensure the survival of Monarch butterflies is to plant clusters of milkweed in your yard.

Another is to begin using Organic Pest Control and IPM (Integrated Pest Management) Methods in your garden landscape.

Milkweed often harbors pests that can ruin a Monarch caterpillar’s meal and threaten its life. Natural predators of the caterpillar are syrphid flies, robber flies, and parasitic wasps, just to name a few.

Flower Fly

Flower Fly

Although Monarch caterpillars taste terrible after consuming juice from milkweed, their predators still try to come after them.

If a caterpillar is threatened, it drops to the ground and “plays possum” but if it falls too far from the milkweed plant, and loses its way, the baby caterpillar will perish. It needs milkweed to survive.

Aphids Attract Predators

Aphids can become a problem because they attract a Monarch’s predators.

You can eliminate aphids by hosing the plant or using a spray bottle with a little dish soap mixed with water but after a few minutes, make sure to rinse with fresh water so the soap doesn’t burn the leaves.

Aphids attract predator insects that destroy Monarch caterpillars.

Aphids attract predator insects that destroy Monarch caterpillars.

Pesticides may be necessary if your milkweed has a major aphid infestation. Hearts Pest Management has organic methods for treating and keeping your plants free of aphids.

Syrphid flies will lay their eggs on infested plants with aphids so that their own larvae can feed on the aphids. Besides aphids, syrphid fly larvae will eat young Monarch caterpillars by sucking their insides out and leaving nothing but exoskeletons!

Also, make sure your milkweed plants are densely spaced, just in case baby Monarch caterpillars have to drop and “play possum,” then they’ll be able to find their way back to their host plant.

Where to See Monarch Butterflies

After two weeks of being closed up in a cocoon, this Monarch butterfly will be free to fly.

After two weeks of being closed up in a cocoon, this Monarch butterfly will be free to fly.

Beginning in the month of November, you can view overwintering Monarch butterflies in our sunny, southern California cities.

When next you see a Monarch, think about the amazing journey these little creatures make each year.

Oh, and maybe plant some milkweed in your garden. …

Here are just a few of southern California’s roosting areas for overwintering Monarchs:

San Diego: Grape Street Park, Balboa Park Huntington Beach: Huntington Central Park Long Beach: El Dorado Nature Center

Author’s Note:

Since I started writing the blog for Hearts Pest Management, I’ve always wanted to write about butterflies. …

There is a certain element of freedom and abandonment that I imagine is mine when I see a butterfly flitting about, from flower to flower, across streets, and through meadows.

One reason butterflies fascinate me is because I have been referred to (over the years by various co-workers) as a butterfly. When I’ve asked why, I was told it’s because I have a “delicate and sensitive nature” …

…but guess what? Butterflies may look delicate but are so strong and persevering, they can fly through prevailing winds just to get to where they want to go!

Donna M. Walker

Donna M. Walker

References / Photos and Design:

Thanks to Trish Kydd for photos of the chrysalis, caterpillar, and evolving Monarch butterfly which she nurtured in her garden.

Photo Editing and Design by Donna M. Walker

Schoenherr, Allan A. 1991. A Natural History of California. Berkeley: University of California Press. en.wikipedia.org/wiki/Monarch; Viceroy; and Queen butterflies USDA Forest Service, 2013. Monarchs and Milkweed. Online: fs.fed.us.com Where to See Overwintering Monarchs. Online: monarchprogram.org North American Butterfly Association. Online: naba.org/quanda

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