Posted tagged ‘monarch migration’

The King is Dead: Appreciating a Monarch Corpse

September 30, 2012
still life with monarch butterfly

Late-summer still life: monarch butterfly with flowers and tomato

I’m still seeing monarchs here at the East End of Long Island, but the big wave of migrating monarchs seems to have passed.

In response to my earlier post on monarchs, Philadelphia nature blogger Donna Long of In Season wrote that the monarchs I saw flying southwest were probably heading to a well-known gathering spot at Cape May, New Jersey, where they rest before continuing south. And British blogger Mark Wilkinson of The Badger’s Eye, wrote from England to say that a monarch, apparently blown off course on its way to Mexico, had crossed the Atlantic and turned up in England. There it caused a stir among British birders, who trekked from far and wide to view the (to them) exotic creature.

Monarchs may not be exotic here on the eastern coast of the United States. They may even be ordinary. But as Julian Hoffman writes in a lovely post called “The Wonder of Ordinary Places,” there is a mode of perception whereby “the ordinary transforms into the extraordinary.”

Last week, after a night of fierce winds and some rain, I found a beautiful male monarch butterfly dead on the grass.

dead monarch butterfly

Lower body is coming through the top of the wings. (The legs are on the other side.)

The monarch is an extraordinary combination of fragility and strength. In the photo below, you can clearly see on the right one of the places where the wing has torn. (Note also the heavily furred body and the small bulb at the end of the antennae.)

Torn butterfly wing

Worn wings.

Yet this tiny animal is capable of flying thousands of miles to migrate to its winter hibernation spot in Mexico. In fact, scientists have reported that by the time monarchs reach their winter habitat, the wings are often torn and worn, sometimes severely.

Looking closely at the little corpse, I first wondered if it was deformed. The legs seemed to be located above the wings, as if on top of the body.

The rest of the butterfly’s body has slipped through the wings to the upper side.

A deformed monarch put me in mind of Shakespeare’s King Richard III, attacked by Lady Anne as a “foul lump of deformity.”  But in fact, the butterfly’s lower body has simply slipped through the opening between the wings and emerged at the upper side of the wings.  In other words, the legs are where they should be, but the lower body has moved.  According to my research, this is not an uncommon death position for a butterfly.

Deformities in butterflies are not uncommon and most often involve the wings. When a butterfly emerges from its chrysalis, it must dry its wings and allow them to “set.” If the animal falls from its perch or doesn’t have space to freely open the wings, the wings can crumple or bend.  In addition, if the chrysalis has been damaged during metamorphosis, the adult butterfly’s body will reflect that damage.

You may wonder how I can so confidently assert that this butterfly is a male.  Male monarchs can be identified by  tiny scent glands. Look for a small black spot on a vein of the hind wings, clearly visible below.

Scent spot on wing of male monarch butterfly

Scent gland visible on hind wing of male monarch butterfly

Scent glands, found on many butterfly species, emit female-attracting chemicals during courtship. Had this butterfly survived to complete a successful migration, he might have used these spots to court and reproduce next spring.

Instead, he’s part of a late-summer still life.

late summer colors

Late-summer still life 2.

Monarch Migration

September 14, 2012

Farewell to the monarchs, beautiful kings and queens of the insect world.  

Monarch butterfly stocks up on nectar for the long flight south.

Monarch butterflies are fluttering and feeding all over eastern Long Island right now. They’re in the garden, by the roadside, and over the fields, preparing for fall migration to Mexico.

Monarch Watch, a website devoted to monarch conservation, estimates the peak days in “monarch abundance” to be September 8-20, so we’re right on schedule.

The monarch life cycle is extraordinary, as it takes several generations to complete a year’s cycle. Every fall, eastern monarchs migrate thousands of miles to spend the winter in Mexico’s Sierra Nevada. In March or April the butterflies return to the southern United States, seeking milkweed plants on which to lay their eggs.  The migrant generation will die before reaching the northern states.  Further colonization depends on the next generation.

After four days or so, the caterpillars hatch. They live on milkweed for about two weeks until fully grown.  Then they spin a chrysalis, inside which they metamorphose from caterpillar to butterfly. They emerge after about 10 days, and continue their parents’ journey north, laying eggs as they go.  The next generation of eggs will hatch in May and June, the third in July or August.  These butterflies will live just two to six weeks.

But the fourth generation of monarchs, emerging in late summer or early fall, will live as long as eight or nine months. These are the migrants that complete the cycle, flying south in early fall and returning in the spring.

They must survive wind, weather, and automobile windshields. Hungry birds are less of a threat since the caterpillar’s milkweed diet makes the monarchs poisonous to most birds or, at least, bad-tasting. The biggest threats to the monarch’s existence are climate change and illegal logging in Mexico, although recent reports from the World Wildlife Fund indicate that logging within the butterfly sanctuary has ceased.

To help scientists learn more about monarchs, you can participate in a citizen science project at Monarch Watch, tracking butterfly sightings and even tagging the insects with tiny tags.

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