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/

 

Busy as a bee is no joke! Our hardworking pollinators – pretty and persevering!

honey-bee-brazilian-sage-i77a1269-maria-de-bruyn-resHere it is, 7 November, and the honey bees were still busily working over the Brazilian sage, lantana and chrysanthemums in my garden. The Eastern carpenter bees were absent today, perhaps because of the cold night we had, but a few butterflies were flying among the flowers. We know that some of our pollinators are in serious trouble, but my garden has nevertheless been blessed this year with a steady stream of pollinating visitors who were to be seen on the varied blooms morning, noon and almost night.

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I’d enjoyed seeing the bees, butterflies and syrphid flies in the past, but started paying even more attention to them as pollinators this year as I worked on the “Healthy Bee, Healthy Me” project initiated by the non-profit organization Keep Durham Healthy.

 

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The project expresses its goal as follows: “…to establish educational pollinator gardens in proximity to pre-existing community gardens to ensure the sustainability of nectar and pollen sources for our honey bees, native bees, butterflies and other pollinators throughout the year, and to increase the yield of the food crops grown within the community gardens.” Some of my photos were used in one of their interpretive garden signs and next year more community gardens will join the project.

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Science knows that more than 250,000 plants are pollinated by over 100,000 different types of animals, but not all plants require assistance from pollinators for fertilization. In abiotic pollination, fertilization occurs without another organism as an intermediary – for example, through movement of pollen from male vegetative anthers to female stigma by the wind (called anemophily) or water (called hydrophily). However, much fertilization occurs with assistance from biotic vectors, which not only include bees, butterflies and flies but also moths, birds and mammals (e.g., lemurs, squirrels, opossums, monkeys and bats; here you see a hummingbird clearwing moth – Hemaris thysbe – getting nectar.) How cool is that!

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The most efficient pollinators are the bees. Some species like honey bees (Apis mellifera) and bumble bees have pollen baskets (corbiculae) on their legs – a concave portion of their hind leg in which pollen can be stored as a ball. It starts out small but eventually gets fairly big so their little tibia begin to look like barbells. The color of the pollen can differ from bright yellow to brown to red to white, depending on the pollen of the flowers visited most often.

 

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American bumble bee (Bombus pensylvanicus)

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Common Eastern bumble bee (Bombus impatiens)

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Honey bees

The attractive little honey bees, which vary in their coloring, are known to pollinate about one-third of the popular foods eaten by humans, including items such as tomatoes, peas, beans and other fruit.

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ruby-throated-hummingbird-i77a1315-maria-de-bruyn-resWhen visiting tubular flowers, like the Brazilian sage (Salvia guaranitica), the bees don’t look for nectar by entering the flower as do the ruby-throated hummingbirds (Archilochus colubris) with their long bills. Rather, they alight on the base of the corolla tube so that they can drill down into the flower to extract the nectar at the source.

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Honey bee                                                  Eastern carpenter bee (Xylocopa virginica)

The clearwing moths and butterflies, like the Eastern tiger swallowtails (Papilio glaucus), have long tongues that they use to probe the flowers as they hover. Nevertheless, they can get pollen on their legs or bodies and transport it to another plant, although they are not as efficient at this as, for example, the sweat bees and carpenter bees.

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These bees have scopae rather than pollen baskets on their legs, i.e., structures comprising dense masses of compressed hairs into which pollen grains are pressed.

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Small carpenter bee (Ceratina)

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Female sweat bees (Augochlorella)

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Long-horned bee (Melissodes)

Sometimes the bees manage to get their whole bodies covered with pollen, which can make species identification more difficult but creates some interesting views.

eastern-carpenter-bee-i77a2601-maria-de-bruyn-res    eastern-carpenter-bee-i77a3750maria-de-bruyn-res

four-toothed-mason-wasp-monobia-quadridens-i77a2039-maria-de-bruyn-bgWasps can carry pollen as I saw almost daily when the four-toothed mason wasps (Monobia quadridens) visited my yellow passionflowers (Passiflora lutea). Here you can see the pollen collecting on the head of a male, whose sex can be determined by the fact he has 7 abdominal segments and curved antennae (females have straight antennae and 6 abdominal segments). How’s that for a bit of obscure information for the non-entomologist?

The syrphid flies, often known as bee mimics, help pollinate, too. A number of these flies are honey-bee size and can be confused with the bees easily.

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Flat-tailed leaf-cutter bee (Megachile mendica)

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Transverse flower fly (Eristalis transversa)

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Syrphid fly (Eristalis dimidiata)

Others are itsy bitsy, tiny flyers that can have pretty interesting abdominal patterns. I couldn’t see the patterns even with my glasses on; enlarging the photos revealed their beauty, which could make for interesting fabric patterns in my opinion.

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Syrphid fly (Toxomerus marginatus)                      Syrphid fly (Toxomerus geminatus)

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Syrphid fly with a lovely golden sheen (Eupeodes subgenus Metasyrphus)

The pollinators don’t appear to begrudge one another nectar – different species will share space on particularly popular plants.

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Eastern carpenter bee and monarch butterfly (Danaus plexippus)

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Eastern carpenter bee and sweat bee

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Eastern carpenter bee, sweat bee and syrphid fly

Occasionally, the pollinators do not live out their usual short lifespans as predators catch them for food. This Chinese mantis (Tenodera sinensis) had been eyeing a bumble bee and was slowly moving toward it but the bee flew off before the mantis could complete its lunge. Later the mantis managed to snag a honey bee, however.

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While on a walk one day, I suddenly was startled by the loudest buzzing I had ever heard, coming up behind me. It sounded angry, intense and was rather piercing for a buzz. I turned just in time to witness a giant robber fly (Promachus) settle on a grass stem with a bumble bee that it had just caught. The buzzing stopped fairly quickly as the fly proceeded to ingest its meal.

 

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Various organizations and agencies, including the US Fish and Wildlife Service, are drawing attention to the endangerment of pollinator species. The main threats include loss and degradation of habitat as we pave over an increasing amount of natural space and plant lawns instead of native plants in yards. Using pesticides in landscaping areas is further threatening many of the insects on which pollination depends.

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Planting pollinator gardens is a way in which we all can contribute to saving our pollinators; if you don’t have your own yard, you can volunteer with a project to create a community garden. And then you can watch these fascinating insects with appreciation for their contributions to us!