I'll Drink to That

Long distance feeding - proboscis of the convolvulus hawk-moth_(Agrius convolvuli)

Snail proboscis - Wikipedia

The last blog discussed the anatomy of the incredible lepidopteran proboscis.  Before we go further, I need to point out some other species which have a proboscis.  Some other animals, including snails, as seen on the right, use long, prehensile proboscis for feeding on a dead fish.  Some other species have a proboscis used for function, beauty or just a good laugh.

Proboscis monkey - Wikipedia

In mammals the elephant trunk wins the function award but there are other famous contenders as well.  Consider Jimmy Durante, a comedian who made a career of poking fun at his nose as in his song Boys with the Proboscis.

Jimmy Durante - Wikipedia

Elephant seal  - Wikipedia

Great spangled fritillary on sweaty head

Some butterflies collect fluids that go beyond gross as described in Blood, Sweat and Tears.  Sweat feeding is not uncommon and some species like the hackberry emperor can be aggressive, landing repeatedly on sweaty surfaces even when brushed away.  I have had several land on me at the same time, evading my net by landing on my head.  Before this makes you feel special, they also feed on dung, mud puddles and animal urine.

Lachryphagy in the Peruvian Amazon  - Phil Torres from Mix

Tear‐feeding (lachryphagous) butterflies and moths can land on a larger animal and essentially puddle around its eye.  They poke their proboscis into the eye to stimulate tear production.  They usually feed on turtles, some mammals and crocodiles (yes, crocodile tears!).  Although lepidoptera don't harvest human tears, there are some bees that do.   "Bees go after the tears instead of sweat since they're 200 times richer in proteins than sweat."

Hematophagous (blood-feeding) moths may get their blood from a wounded surface or by actually piercing the skin.  Calyptra sp. in the Old World all pierce the skin of fruit and 10 species will pierce even tough mammalian skin. Their specialized proboscis has a combination of erectile barbs and tear‐shaped hooks on each galea (half of the proboscis).  "The insect rocks the proboscis from one side to the other, applying pressure until it pierces the skin. It then uses a rocking head motion to drill the tube deeper into the skin. The blood pressure of the victim supplies power to raise hooks on the proboscis to ensure the insect is not easily detached."

Goatweed leafwing butterfly competing with paper wasps - CB

Five Comma Butteflies on a racoon carcass

Goatweed leafwing butterflies are flying in March.  They overwinter as adults, hiding under loose bark, like on shagbark hickory, and emerging on warm days looking to collect sap.  Chris Barnhart describes their thick proboscis that can feed on fruit and they will stick it right under the mandibles of paper wasps which are competing for the same food as in his photograph above.

Happy hour on the deck - Chris Barnhart

Although they may use their wings to bat away competitors, butterflies can also become quite congenial in a puddle of the right kind of fluid as seen above.  This was sap leaking from several spots on a tree and probably fermenting from a yeast infection.  It was a popular hangout for several weeks.  If only all of our human communities could get along like this!

The Incredible Proboscis

Proboscis in two halves

In the last blog we mentioned that when butterflies emerge from the chrysalis, their proboscises consist of two C-shaped fibers called galeae, which are then united, sealing the halves into a flexible elliptical tube.  So how do the two halves come together to form the functioning tube?  Self-assembly of the Butterfly Proboscis from Clemson describes the process which includes the butterflies' saliva and capillary forces.

No muscle action is required to hold the parts together.  Asknature.org has  technical descriptions of the linkage mechanisms.  This linkage also allows the proboscis to remained coiled without the use of muscle, reducing its energy requirements.

So once the two galeae are sealed together, is that a permanent bond?  I can recall a grade school bully who used to pull the wings off of a butterfly.  In a more scientific version, Suellen Floyd Pometto and colleagues separated the two halves of the proboscis in the name of science.  She performed this on monarch (Danaus plexippus) and painted lady (Vanessa cardui) butterflies, then studied the repair process.  Both species were able to accomplish repair of the proboscis, with variable rates of success.  Those achieving reunion of the galeae had recovery of the coiled resting state and dye studies then confirmed that the restored proboscises functioned normally.

Convolvulus hawk-moth_(Agrius_convolvuli)

That same paper also provides an in depth look into lepidoptera feeding strategies as well as the functions and mechanisms of the proboscis.  It also provides a listing of the 19 different muscles that control the proboscis in slurping up fluids.  The lepidopteran proboscis is a versatile tool to obtain different sources of minerals and food.  Some species are even able to pierce fruit and mammalian skin as discussed in the next blog.

Winter Chrysalis

Sharon Hughes gave me this pupa at our Master Naturalist meeting on Monday.  Her husband found it hanging from the top of the door frame between the screen door and the front door. It looked like a butterfly chrysalis including a telltale string of silk with which it had suspended itself, waiting to spread its wings with the help of gravity.  Alas, winter had caught it and literally frozen it in time.

Kevin Firth identified it before the ink dried on my email request.  This is a spicebush swallowtail chrysalis, characterized by the two diagnostic anterior 'horns'.  We discussed the caterpillars in last June's blog.      The photographs below from the University of Florida will show how the chrysalis is suspended in nature.  The picture, on the bottom left, gives a better idea of where the wings will emerge and you can even make out the spiracles.

Photo by Donald Hall

Photo by Donald Hall

Since this had been found on a door jam outside of the front door, I had little hope that it would survive the freezing temperatures.  Just in case, I kept it in a bug box to watch.  One afternoon as I walked by the kitchen counter (my wife is a saint) I saw something move out of the corner of my eye. Turning to the box, I lifted the opaque lid and there was the eclosing butterfly. I started a video and then moved it to a larger container with an upright dried twig which it immediately climbed up on. 

You can see the video of its emergence here. Watch closely and you can see it repeatedly extend and curl up its proboscis.  When they emerge, the proboscises of butterflies and moths consist of two C-shaped fibers called galeae, which are united after the insect emerges from the pupa, sealing the halves into a flexible tube.  Here you can see the two halves of the proboscis haven't sealed together yet and the left wing is curved and withered although it is flattening out over time. Eventually it was able to fly around in its aquarium.  The bluish color on the dorsal hindwing confirmed it was a female.

Proboscis in two halves

Empty chrysalis

Proboscis sealed at last

The problem now was that the outside temperature was a high of 30 degrees, dropping to 10 degrees at night.  By putting it in our warm house we had interrupted its winter diapause. With a lifespan of several weeks at best, even if it warmed up she had no nectaring sources, no male available, and no food plants for her eggs. She had no outlet for her biological imperative.  In retrospect, her only extremely long shot at reproduction would have been keeping the chrysalis in the refrigerator until our spicebushes leaf out in 10 weeks.

Of course that is all from an anthropomorphic perspective as no one knows what a butterfly perceives.  With a beautiful and delicate creature, it is natural to empathize and impart our human values.  While it was a hopeless situation for this creature, the only realistic response is to to do what Sharon did and in its memory plant spicebush (Lindera benzoin) and sassafras (Sassafras albidum), its alternate host plant, as well as native plants for nectar.  This spring, carpe diem. Then, like Sharon, you'll be able to say "I grow spicebush so that makes me happy to know the little guys have found my plants"



More on proboscis closure is in this paper.
For much more detail on proboscis function try this source, and may the force be with you. 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4043169/ 

Globe Traveling Monarchs

Monarchs down under - shredding milkweed in Auckland - CB

While hearing all about our friends' Chris and Deb Barnhart's recent travels to New Zealand, I was astonished to see photographs of large populations of our beloved monarch butterflies, Danaus plexippus.  It turns out that the migrations we follow as a marker of our environmental health are just a small part of their travel itinerary.

Monarch distribution in orange (arrow points to New Zealand ) - Wikipedia

"Easy with the hands, mate!" - CB

For those whose geography is a little rusty like mine,  New Zealand is made up of two long large islands southeast of Australia.  It is the southernmost home of "our" monarchs.  The map labels above suggest their earliest arrival times.  They are distributed in many South Pacific islands as well as Australia.  Now notice the small yellow circles in the Atlantic Ocean and the southern area of Spain.

"Our monarch"is D. plexippus while a sister species Danaus erippus, occurs only in the lower 3/4 of South America. Its appearance and genome is nearly identical to D. plexippus.  The two are sexually incompatible, meaning that they don't reproduce when mated together and therefore considered separate species. Wikipedia

According to Monarchlab.org, our monarchs arrived in North America from a migratory ancestor, common to both D. plexippus and D. erippus. When the last ice-age began receding 20,000 years ago, "the monarch population occupying the southern USA and northern Mexico began to grow and expand their range and migration annually. These expansions were stimulated by the abundance of milkweed that was growing, exploiting the novel habitat uncovered by the glacial recession. The population underwent three separate dispersions into South America, westwards to Oceania and Australia, and east across the Atlantic"

"Monarchs are native to North and South America, but spread throughout much of the world in the 1800's, though recent analysis supports earlier dispersal (Kronforst et al. 2014)). They were first seen in Hawaii in the 1840's, and spread throughout the South Pacific in the 1850's-60's. In the early 1870's, the first monarchs were reported in Australia and New Zealand. Monarchs also inhabit Portugal and southern Spain along the Iberian Peninsula, and the Mediterranean habitat offers a suitable environment for monarch butterflies to proliferate."

I asked Chris how they got to New Zealand, I was startled when he said by airplane.  It turns out that he meant their trip and even he doesn't have the answer for the monarchs' transportation.  Monarchlab has a lot of information on the various hypothesis as well as the relationship to the arrival of milkweed.

Monarchs are recent exotic arrivals but welcomed species in New Zealand and other locations across the South Pacific.  They have few enemies and milkweed resources are available.  The climate allows them to thrive without the long commutes of our native monarchs.  Since they spread freely without causing any appreciable harm, some Australians refer to them lovingly as "flying weeds".

The wide separation and relatively recent separation of colonies gives genetic science an opportunity to study the effects of newly implanted small populations, the so called founder effect.  Berkeley.edu describes this as "population bottlenecks occurring when a population's size is reduced for at least one generation."  In this case, if only a few monarchs make the trip across the wide ocean expanse, they might be limited in genetic diversity compared to the population as a whole.  Their article gives examples of this.

Some final thoughts from Chris Barnhart:
"Monarchs are in NO danger of extinction as a species anytime soon. Monarchs are doing just fine, along with the cabbage butterfly, starlings, cockroaches and others that have been made global by human activity. Humans planting milkweeds let monarchs colonize places they never could have survived before. Yes, we should care about keeping monarchs abundant in the US, because the migration is a wonderful thing. But the monarch is not the only amazing species and certainly not the most endangered or the most in need of attention in our area.

We should be planting more than milkweeds.  Planting an oak tree will help over 500 species of native insects and the birds that feed on them.  Milkweeds and monarchs might be effective poster children, but I think that too many people are missing the bigger picture.  Doug Tallamy’s books and websites are a great source of how-to information on native host plants for butterflies and other wildlife. We have lots of examples in the Roston Butterfly House.  If you plant for them, they will come!"
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Update  3-17-2019
Monarchs have lost the long-distance migration record.  Science confirms that Painted Ladies make an annual journey of 7,500 miles from Spain over the Sahara desert to southern Africa!

For a fascinating Australian view of monarchs, or Wanderers as they call them, check out this web site.  It describes their migration strategies that vary with regional climates, with some  "over-wintering" by hanging from the branches of trees in large clusters of thousands of butterflies.

Green Lep

Chris Barnhart challenged me to identify this photograph.  It didn't look like feathers and I don't know any mammal with green hair so I settled on an insect.  Knowing Chris, I was betting on a lepidoptera.  I asked him for another hint but instead he sent another picture.  That didn't help at all.  When I gave up he sent a photo of the whole critter.

This is a Pandora sphinx moth, Eumorpha pandorus.  I had never seen one so brilliantly colored, a testament to his photographic skills.

Pandora - Chris Barnhart

A Pandora caterpillar is large with colors from green in the first instars transitioning finally to dark orange-brown.  It has an unusual super "turtle power" -  the ability to pull its head into its body.  The swollen third thoracic segment stretches to allow the head and first two thoracic segments to be pulled in, like pulling up a turtleneck sweater.  Chris' photograph will give you the idea, as well as the photographs below by Patrick Coin.

"Now you see it..." -  Patrick Coin

"Now you don't" -  Patrick Coin

This is all a reminder that it will soon be spring, the time to look for caterpillars and the opening of the Bill Roston Butterfly House at the Botanical Center on May 18th.