Monarch Caterpillers!

For years, my husband and I have nurtured milkweed in the lost corners of our yard. “Remember the Monarchs!” we chant, as we carefully work around the tall milk-sap plants.

While Monarch butterflies eat nectar from a bunch of different plants, the caterpillars eat only milkweed as they grow. The milky sap of Milkweeds is toxic to most animals, but not to Monarchs. In fact, in’s all that Monarch caterpillars eat. What’s more, the Monarch caterpillars incorporate the toxins into their own bodies, and use it as a chemical deterrent against predators.

In spite of this incredibly cool adaptation, Monarch populations have been declining for decades — between 50-90% loss since 1991. Habitat loss has been a major problem in the United States, especially with the introduction of herbicide-resistant corn and soybeans so that herbicides can be sprayed on them to get rid of milkweed growing between the rows. In Mexico, where they overwinter in just a few select spots in upland forests, they are vulnerable to illegal logging operations, cold snaps and hurricanes. Car strikes are also a surprising big killer of Monarchs in Mexico — up to 200,000 killed in just two locations near their over-wintering spots! Monarch Butterfly Migration

There’s not a lot we can do to alleviate these problems. But we can grow milkweed to give as many Monarchs as possible a good start in life. Through the years, we’d been rewarded with a few Monarch butterflies. But no caterpillars.

And lately, we’ve become aware that the decision to grow milkweed is itself a trade-off — native milkweed is attractive to European honeybees, but it can be a deadly trap for them, too. Bees and Butterflies.

Bees are already having a hard time from colony collapse disorder, where the bees just disappear. After years of research, nobody knows why. It’s a major problem with honey bees, one that’s not getting better. I was beginning to feel that if the Monarchs weren’t using the milkweed, we should rip out the it and replace it with something more bee-friendly.

And then, for a real treat …

… my husband found two tiny yellow, white and black caterpillars happily gnawing on our milkweed.

Maybe the milkweed will stay after all.

Monarch on Milkweed

Monarch butterflies are beginning visit our milkweed plants, which always makes us happy.

Monarch butterfly on Milkweed

Although milkweeds can be a trap for honeybees (https://amylaw.blog/2016/07/17/bees-and-butterflies/), they are required for Monarchs to feed and lay their eggs. Monarchs are in steep decline due to habitat loss and herbicide use, so we try to help them out when we can, by growing milkweeds in the odd corners of our yard.

Butterflies Galore

I’m not really an expert on butterflies. But while hiking recently in the Front Range foothills , I saw so many of such varied species that I had to check into them a bit more. All these different butterflies are from just one hike.

Aphrodite fritillaries mating

Aphrodite fritillaries. Yellow-green eyes clinch that these are aphrodites. (Colorado Front Range Butterflies).

Females lay single eggs near violets. Caterpillars do not feed, but overwinter until spring, when they eat young leaves of violets.

Northwestern fritillary

Northwestern fritillary. The eyes of this butterfly are blue-grey and the wings are darker towards the body. Colorado Front Range Butterflies.

These two photos show two species of fritillary butterflies. They tend to be orange with black squiggles.

female Common Wood Nymph-1

Female Common Wood Nymph. The double eye spots are the key to identifying this butterfly. Females are larger and paler than males.

I haven’t found anything talking about this, but every time I saw this female Common Wood Nymph land, she seemed to lay her wings onto the landing surface. In late summer, females lay eggs singly on host plant leaves. Caterpillars hatch but do not feed, instead hibernating until spring. (Butterflies and Moths of North America)

Native bees on Asclepias-13

Dusted skipper butterfly and native bees on milkweed. Although here all the skipper butterfly wings are compressed, they often hold their upper and lower wings a little apart, creating an “X” effect. I am trying to find out more about these very unusual bees.

Skippers are a type of butterfly I had never noticed before I started taking pictures of everything of interest on my hikes.

Taxiles skipper

Taxiles skipper on thistle. You can see his “X” wing configuration here.

Males may defend their territory. (Butterflies and Moths of North America)

I used two websites to learn about butterflies: Butterflies and Moths of North America and Colorado Front Range Butterflies. Both are very cool, but the first has an interactive map where people can post their sightings and photographs of the moths and butterflies they see.

 

Swallowtail Butterflies

Several weeks ago, we had orange and black Monarch butterflies migrating through the Front Range. They seem to have moved on.

But we’ve still got big butterflies in the area — yellow and black swallowtails. I’ve seen two different types of swallowtails. The western tiger swallowtail is lives along waterways and in woodlands, as well as suburban areas. It’s caterpillers eat aspen, cottenwoods and green ash. The eastern version of this butterfly …. hmmm…. lives in the east? That’s all I’ve found to separate the two.

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Western tiger swallowtail on Canada thistle.

The other species of swallowtail that I commonly see in the west Denver area is the two-tailed swallowtail. Predictably, it has two tails.  These butterflies lay their eggs on green ash and chokecherry, although the adults evidently like the nectar from our milkweed plants.

Two-tailed swallowtail
Two-tailed swallowtail on milkweed.

It’s a hard life being a butterfly. This poor guy has survived a lot.

Damaged two-tailed swallowtail butterfly on milkweed.

Swallowtails lay their eggs on their preferred plants. The eggs hatch out into caterpillers, which proceed to feed on their host plants. When winter comes, these larva spin a chrysalis (cocoon), in which they overwinter.

Unlike Monarchs (Monarch Butterfly Migration) or Painted Ladies (Painted Ladies migrate across North America! Painted Ladies Part Two), swallowtails only produce one generation a season. The adult swallowtails emerge in May and June, and continue to be active in the same area through August, feeding on plant nectar, as the butterflies above are doing. Sometime in the summer, they lay their eggs.

Monarch Butterfly Migration

Thanks to the nice weather, I worked out in the yard for a good bit last weekend. As I worked, I saw and heard our normal back yard wildlife — feisty squirrels, black-capped chickadees, house finches, Northern flickers, dragonflies and big yellow swallow-tail butterflies. Then I saw something unusual — an orange butterfly. I assumed it was a Viceroy, because it flew right past the big patches of milkweed we’ve let grow for the Monarchs that might wander through our yard (Bees and Butterflies).

Then I saw another. And another. None of them were landing anywhere in the yard, but I decided to try to photograph them anyway. Maybe one would alight just long enough for me to snap a shot.

As I watched them more closely,  I began to have a niggling feeling that maybe I should check my butterfly identification books. In the meantime, I took a few photos.

Monarchs are orange with black stripes. They differ from very similar Viceroys in that Viceroys have a stripe along their lower wing. Otherwise, they are almost identical. So the photo on the left, taken in our back yard, is a Monarch! I’m glad it stopped by.

Starting in March, Monarchs migrate from Mexico and Southern California to Canada every year, reaching their northern limits in late June. We get our first Monarchs about the same time.

monarch on milkweed (9)-1

Monarch feeding on milkweed in our backyard.

There are lots of astonishing facts about Monarch and Viceroy butterflies. One fact about the Monarchs is that, although they migrate long distances every summer, no one butterfly goes the whole distance. Instead, the overwintering generation heads north in early spring. They mate, lay their eggs and die somewhere along the way. The next generation of monarchs hatch and head north. They mate, lay their eggs and die somewhere along the way. It takes at least four generations to get to the northern-most point in the Monarch migration! The fourth generation then makes the return trip south, and overwinters in the same trees its ancestors did last year. As with other butterfly species (Painted Ladies migrate across North America!), nobody knows how they do it.

You can watch Monarchs as they travel at this website: Lerner Monarch Butterfly Migration Map Spring 2018. They even have a site where you can report your observations! What to Report

 

 

Bees and Butterflies

Our neighbors behind us are turning their backyard into a farm. They have a garden. They have chickens. They have fruit trees. This year, they added honey bees.

We, on the other hand, have always had a hummingbird garden that attracts all sorts of pollinators, including bees. One of the plants that planted itself and we have encouraged is native milkweed.

bees on milkwee (2)

Bees love it. They buzz around the milk weed constantly.

bees on milkwee (1)

But we noticed a problem lately — some of the honey bees are getting caught in the milkweed flowers.

bee caught in mikweed closeup

Honeybees are non-native — they are from Europe and Asia. Milkweed, on the other hand, is native to North America.

Bee caught in milkweed

Close up of honeybee foot (tarsi) caught in milkweed polonium.

The bees’ claw-like feet get caught in a structure called a polonium. This is actually exactly what is supposed to happen with the polonium. The polonium is full of pollen, and the insect is supposed to catch it on its feet, pull it free and take it to the next milkweed. The “Mydas” Touch/Eye on Nature

Unfortunately for the honeybees, they aren’t strong enough to pull free. If they are well and truly caught, they are doomed (we free the ones we find in our garden).

So why don’t we pull up the milkweed? Because it is of critical importance to endangered Monarch butterflies. Milkweeds are the only plant that Monarch butterflies lay their eggs on.Milkweed is slightly toxic to a lot of animals, but not to Monarchs. The Monarch caterpillars hatch out, eat Monarch leaves and become slightly toxic themselves.Monarch Butterfly Habitat/US Forest Service

Bees are in trouble from the baffling Colony collapse disorder, but Monarchs are threatened with extinction, in part due to the loss of milkweeds.

monarch on milkweed (9) -1

Monarch on our backyard milkweed.

Sometimes, you have to make choices on what you help out.