Helping monarch butterflies thrive

If you follow news about nature, you may have come across warnings that the monarch butterfly (Danaus plexippus) has been in rather dire straits for many years now.

 

These lovely orange and black butterflies live from 6 to 8 weeks when they are adults engaged in reproduction. Those who live in the Eastern USA participate in a multi-generational migration process between Canada and central Mexico. The last generation to emerge in late summer is able to delay its sexual maturity to undertake the last leg of the migratory journey (called reproductive diapause) and may live up to 8 months. Individual butterflies may travel as far as 1200-3000 miles to get to their warmer over-wintering grounds.

 

Since the 1980s, the Eastern US monarch population has declined by about 80%, mainly because the only food source for their caterpillars has been disappearing. Milkweeds used to grow abundantly in agricultural areas and along roadsides and ditches, but people have been eradicating the plants from fields and using herbicides and mowing to remove them along roads.

Climate change has also affected the butterflies’ breeding and migratory patterns so that reproduction has been reduced.

One way to help out the monarchs is to plant native (not exotic!) milkweeds in your own yard and any other natural spaces to which you have access. I’ve been doing it around my home and as a volunteer for the Mason Farm Biological Reserve. This year, I was lucky enough to be a beneficiary of a milkweed give-away organized by some local high-school students, so I had two types of the plants in my yard.

 

The ones that I had originally planted were common milkweed (Asclepias syriaca). These plants have large globular clusters of flowers that range in color from pinkish to purple. They do not have blooms their first year but that doesn’t stop the caterpillars from eating their leaves.

 

Butterfly weed (also known as butterfly milkweed; Asclepias tuberosa) is a bit more delicate and “exuberant” in appearance, with small clusters of orange, reddish and yellow flowers. These were the plants that I was gifted by the students and I was happy to see them grow quickly to exhibit their beautiful blooms.

According to Wikipedia, the butterfly milkweed is not a preferred plant for the monarch but this year the butterflies seemed much more attracted to it than to the common milkweed. After a few visits from some butterflies, I began seeing caterpillars and at one point counted 17 crawling up and down the various plants.

They were especially prevalent on the butterfly weed in my front yard and were munching the plants to bare stems very quickly.

 

       

To make sure they had enough food, I transferred some of them to the common milkweeds in my back yard – these were larger plants with much broader leaves and I thought this would ensure their healthy development. Frass (poop) was being left on the remaining leaves and the ground surrounding the plants.

 

It was rewarding to see three caterpillars make it to the chrysalis stage; the other caterpillars crawled away before I could see where they went, and I didn’t find them suspended from any plants. The first one had attached itself to a bare sapling and, unfortunately, the next day it had disappeared, leaving only the silken thread by which it had been suspended.

The caterpillars store milkweed glycosides in their bodies, making them toxic to many other animals. They still have many predators, however, including wasps, spiders, other insects, lizards, toads and mice. I resolved to save at least one chrysalid if I could.

I got to see the second chrysalis being formed (see the video, which is a little shaky at times). When the caterpillar is ready to undergo the pupation stage, it attaches itself to a plant stem by making a silk pad as an anchor (called a cremaster). Then it inserts the hooks at the end of its abdomen into the pad and hangs down. When the caterpillar forms a J shape, this signals the change to a chrysalis will soon be underway.

Starting from the head, the outer skin is shed, rolling up as the new covering develops. The shed skin may remain at the silk pad or fall off.

 

Slowly the stripes of the caterpillar disappear, and the chrysalis takes on a shiny even green hue, with some golden accent spots.

 

I kept that chrysalis, as well as a third one I saw the next morning, in my house and waited for them to darken. This signals the butterfly is almost through developing inside.

One morning I found the newly emerged monarch from the second chrysalis drying its wings. I took it outside so that it could fly free and then begin its trip to Mexico. (I also took the third one outside when it darkened but the twig holding it disappeared.)

 

You, too, could contribute to their propagation by planting some milkweed if you have an area for this. Autumn is the best time to plant seeds, but you can try it in the spring as well. Common milkweed typically doesn’t flower during its first year, but butterfly weed will give you flowers in its first season; the latter plants may be slow to emerge at first.

Both of these milkweed varieties are perennials so be sure to remember where you planted them. Common milkweed may spread out with time, while butterfly weed remains where you put it.

 

Other flowering plants will attract the adult monarchs, too, for nectaring, such as asters and lantana.

 

And then sit back next year and wait for the monarchs to arrive, happy in the knowledge that you have contributed to maintaining a favorable environment for their survival.

More ideas on how you can participate in the drive to save this iconic butterfly are detailed on a U.S. Fish & Wildlife Service website: https://www.fws.gov/savethemonarch/

 

A lucky, lucky day with monarch guardian angels!

Yesterday my day turned out quite differently from my modest expectations – it was very lucky and truly a day for gratitude.

In mid-August, I had seen a female monarch butterfly (Danaus plexippus) at Sandy Creek Park, an exciting find and testimony to the usefulness of planting milkweed there. John Goebel, Sandy Creek patron, manager and care-taker extraordinaire, had planted about five types of milkweed in anticipation of welcoming these guests and it had paid off.

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A few days ago, on Facebook, the Friends of Sandy Creek Park group announced that the one male and two female monarch butterflies spotted in the butterfly garden had left behind quite a few offspring. As I had not seen a monarch caterpillar in person before, I took off early for the park, where I found three people assembled to count them.  John Goebel kindly told me something about the monarch life cycle.

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He pointed out several larger caterpillars, noting that they were stage 4 or 5 larva. The eggs hatch about 4 days after being laid. The larvae eat the plant on which they were born, shedding their skins four times as they grow, a process taking 10 to 14 days. These stages of growth are called instars.

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monarch DK7A6441© Maria de Bruyn resIn stage 5, the large larvae look for a protected and hidden spot where they can attach themselves vertically. They use their spinneret (not only spiders have them!) to make a silk pad from which they then suspend themselves, hanging down in the form of a letter J. The culmination of this procedure occurs when they straighten out, a sign, John told me, that pupation was imminent, with the caterpillar turning into a bright green chrysalis. There was already one chrysalis when I arrived with two other caterpillars hanging nearby.

 

The milkweed plants were attracting plenty of insect action. Many stems were yellow and orange as they were covered with milkweed bug nymphs and aphids. I photographed several of the 43 caterpillars counted, including a small early-stage newbie, and a number of large specimens that were very busy munching on leaves.

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After a while, I moved on to photographing caterpillars of moth species and looked around for birds or other interesting insects. Then an unexpected and unfortunate event arose and I had to high-tail it to the bathroom (thank goodness Sandy Creek has one that is open much of the year!).

Emerging from the bathroom and walking down the path to my car to go home, I felt chagrin that my nature walk had to be cut short. But if it hadn’t been for the bathroom visit near the milkweed plants necessitated by my gastrointestinal emergency, I would have missed a first-time experience. As I strolled to my car, I glanced again at the hanging caterpillars and noticed one had straightened out. I balanced the need to go home to shower and change clothes with the desire to see a caterpillar become a chrysalis. I had cleaned myself as well as possible and no one else was around, so I stayed.

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The caterpillar that I was watching was hanging quietly on a leaf; the only action came from a small milkweed bug (Lygaeus kalmia) and a large milkweed bug (Oncopeltus fasciatus) that marched back and forth on top, so I turned to the side to photograph an adventurous sibling that had climbed to the top of a nearby plant.

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When I looked back, the pupation had already begun and was progressing apace.

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John had mentioned that it could take under a minute; this caterpillar was a little bit slower but the transformation was quick indeed. I’d seen videos of this before but seeing it live in the wild was awesome. And I got my own bit of video showing the last bit of larval skin dropping off the chrysalis.

monarch DK7A7623© Maria de Bruyn resThe large milkweed bug came back to perch over the chrysalis. Later, John moved this chrysalis because the leaf of the plant could fall off before the 10- to 14-day pupation period is over – everyone wants all the larvae to become full-grown adult butterflies who can undertake the long migration to Florida or, more likely, Mexico. Their loss of habitat in both the United States and Mexico is devastating to the species and action to prevent further losses is still needed.

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As I again prepared to leave, I noticed that one of the other hanging caterpillars was straightening out, so I decided to wait a little while in the hope I would see a second pupation. After watching one caterpillar approach and climb a nearby tree and seeing another trundling through the grass toward the parking lot (presumably headed for a tree further away), I focused on the hanging caterpillar.

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Sure enough, the pupation began – in this case, even more rapidly than the first one I witnessed.

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A difference with this transformation was that the last little bit of caterpillar did not drop off but remained suspended at the bottom of the chrysalis. Most likely, it will fall off later, which is important; if it remains attached, it could damage the emerging butterfly.

MONARCH buttterfly 1© Maria de Bruyn resWatching this part of the butterflies’ metamorphosis was an exciting event. I didn’t wait fora third pupation, however, as I really did need to get home. On the way back, I nearly had a collision with another car – perhaps leading the other driver to need a shower, too. At home, I later almost fell on my face as one of my cats wound himself through my legs as I walked so that I came very close to tripping. Both accidents in the making didn’t happen, thank goodness, so maybe the monarch pupae had become my guardian angels for the day. In any event, I did have lots to be thankful for!

 

For more information:

http://monarchlab.org/biology-and-research/biology-and-natural-history/breeding-life-cycle/life-cycle

http://www.learner.org/jnorth/tm/monarch/ChrysalisFormationLPB.html