Friday, September 13, 2019

Day 24: the emergence

Metamorphosis Watch: Day 24 

If you wade into nature observing it closely, you discover that miracles happen every day. But perhaps none more dramatic than what we have been watching the past 24 days. 

From tiny egg to larva to sherbet-green pupa inside a chrysalis to black and orange winged adult. 

Remember the exoskeleton or shell of the chrysalis is transparent, a window to the change and today that change was very apparent after eleven days our monarch butterfly is ready to emerge.

The caterpillar grew slowly. The transformation of the pupa took days as cells moved about and realigned themselves. But emergence happens quickly, a matter of minutes. It is a deeply moving miracle to behold. 

But birth, like all birth, is a struggle. After freeing its head and antenna it must reach out and with its new legs grab a hold of the chrysalis shell. And cling tightly so that it doesn't fall while it frees its abdomen and pump its wings full of hemolymph, insect blood.

This is what we have waited for and as you might suspect, the new life form is born head first. It sees the world for the first time with its new eyes, feels the world with its new legs for the first time, and soon flaps its new wings to fly away. 

Being a good steward, I took the butterfly back to the same damp ditch where I found the egg over three weeks ago. There I tagged it and released it only a few feet away from its original common milkweed plant. Its Monarch Watch number is ABAZ236. Should you happen to capture it along its way to Mexico, you will now know is provenience.

Such miracles as metamorphosis happen millions of times a day. Roughly, half the species on the planet go through complete metamorphosis, so it is  an evolutionary strategy that has proven to be successful over the millennia.

Thursday, September 12, 2019

Day 23: coalescing

Metamorphosis Watch: Day 23  

Coalescing. Isn't that a lovely word? After spending ten days observing the coalescence of the monarch butterfly cells—rearranging themselves from caterpillar to winged Lepidopteran, the wait is almost over. But for the butterfly, its journey is only about to begin. Our metamorphosis watch is starting to get very interesting: emergence is near. The last of the miracle is soon to unfold and quickly thereafter, fly away.

After ten days in the chrysalis our monarch butterfly pupa has changed. We have been looking through the glass, darkly. But not now. Today, we see the black and white of the head, thorax and abdomen cradled between the black and orange of the wings. 

There is still a foggy look created by the cellular material that has yet to coalesce into the adult butterfly but, trust me, almost all will find a home. 

Stay tuned. 


Wednesday, September 11, 2019

Day 22: golden crown

Metamorphosis Watch: Day 22  

Many different butterfly chrysalises develop golden markings. The word chrysalis itself comes from the Greek word: chrysos, meaning "gold." 

As to why they do it is a mystery. Perhaps the jewels help to make the pupa look non-living, non-edible with the reflecting glitter serving as a royal camouflage. How it does it is easier to determine. The raised beads are created by their structure, layers of chitin filled with fluid that act like mini prisms to reflect the color yellow-gold. But again, we are back to "why."

At this point in any natural history question the answer has to be, "because it works. 200 million years of evolution has rewarded the processes that are successful." 

Similarly to the jewels, an indigo bunting's feathers are internally structured to reflect a dark blue sheen. Otherwise, it would be another black bird. 

At Day 22, the kids in the back seat are asking, "are we there yet?"

Stay tuned.

Tuesday, September 10, 2019

Day 21: taking shape, behind closed doors

Metamorphosis Watch: Day 21  

If you could see inside the monarch chrysalis, you'd see the butterfly forming. The abdomen is at the top with the thorax and head below it. To the left the outline of one wing is beginning to take shape while the legs and proboscis are on the backside. Very soon, this will all become very apparent. 

Stay tuned.

Monday, September 9, 2019

Day 20: caterpillars weave silk too

Metamorphosis Watch: Day 20  

Today, we take a closer look at the silk pad or button the monarch butterfly caterpillar spun, its last official responsibility as a larva. The spinneret is located below the mouth and when the pad is finished, the caterpillar turns around to grasp it with its anal prolegs followed by the insertion of the black stemlike cremaster located on its rear end. The anal prolegs fall off with the molted skin. 

Spiders weave silk as well, but an hour's work for them is far less critical than the hour or so it takes a monarch caterpillar to create the anchoring silk pad. For up to ten days, the chrysalis must hang from it through all kinds of adverse weather.

Will it hold tight?  Stay tuned.

Monarch caterpillar spinning the silk pad with its front end
Monarch caterpillar grasping the silk pad with its rear end

Sunday, September 8, 2019

Day 19: through the chrysalis, darkly

Metamorphosis Watch: Day 19  

Again there appears to be little change. Yet, keep in mind that change is indeed happening. The exoskeleton or shell of the monarch butterfly chrysalis is as transparent as cellophane. It serves as a window to the evolutionary miracle that is taking place. The green we are seeing is the living butterfly as a pupa. As time goes by, we will start to see the black, white and orange structures forming and soon will see it face to face. But for now, we see through the glass, darkly. 

Stay tuned.

Saturday, September 7, 2019

Day 18: pulling itself together

Metamorphosis Watch: Day 18  

There appears to be little change. The chrysalis has not moved yet inside there is indeed movement. The monarch butterfly is breathing, its long chambered heart is beating while it is pulling itself together. 

Stay tuned.

Friday, September 6, 2019

Day 17: Busy at work

Metamorphosis Watch: Day 17  

Ditto from yesterday. The monarch butterfly is busy at work inside its chrysalis.

Stay tuned.

Thursday, September 5, 2019

Day 16: Now we wait

Metamorphosis Watch: Day 16  

We're back in a small package. It looks tranquil enough but inside the monarch butterfly chrysalis there is a evolutionary miracle in progress. The pieces are realigning themselves with the imaginal discs. Groups of cells that will become the recognizable butterfly we all know.

The fossil record of ancient Lepidopteran—moths and butterflies—go back at least 200 million years. Both groups go through metamorphosis: egg to larva to pupa to winged adult. So how did the miracle begin? When did the first caterpillar change itself into a winged adult and fly away? And how did it conceive to do such? How? How? How?

That is the miracle.


Wednesday, September 4, 2019

Day 15: The miracle begins

Metamorphosis Watch: Day 15  

Day of excitement! 

Reams of text have been written about this: articles, columns, books, theses. I even wrote about it in my third book for UT Press: Ephemeral by Nature

We first learned about butterfly metamorphosis in third or fourth grade. Were we mystified? Well, yes!

How could this be? One life-form becomes another while all the while retaining its singular identity. But somehow until you sit and watch the process up-close, it still doesn't sink-in what an absolute evolutionary miracle it is. 

Today began with the monarch butterfly caterpillar we have been watching for two weeks hanging head down. Its cremaster was embedded in a silk pad it had just spun with its spinneret. It has to do this because it needs to molt its last larval skin and create an isolation chamber to reform itself.

Is it just a green goo that has to rearrange its cells? No, not really. Because inside that caterpillar all along were clumps of cells called imaginal discs that will now begin to grow into the butterfly organs it will need for its new winged life. The nascent wings, legs, proboscis, eyes, are there all along and now it is time for them to mature. But at no time does this wonderful life-form stop breathing. Its heart still beats.  

You could say it goes on hiatus but that suggests it is somehow resting and it isn't, the monarch has a lot of work to do.

And it all happens inside its chrysalis. A perfect chartreuse green jewel. It is now a pupa.

Stay tuned.


Tuesday, September 3, 2019

Day 14: Let's go for a walk

Metamorphosis Watch: Day 14

Right on schedule. Two weeks after it hatched, the monarch butterfly caterpillar decided it was time to stop eating and go for a walk.

Like all insects, monarch caterpillars have six true legs near the head on what will ultimately become the butterfly's thorax. But they also have five sets of fake legs called prolegs which they mostly use to hang onto leaves and for this, the most important walk of their young lives. They have to climb and find a safe place to hide and pupate, to shed their last larval skin.

They may spend hours trundling along, climbing, to locate just the right spot. After that, the prolegs will never be needed again. 

Stay tuned. 


Monday, September 2, 2019

Day 13: eating is almost over

Metamorphosis Watch: Day 13

When the monarch butterfly caterpillar gets to be roughly two inches long, you know pupation is near. After almost two weeks of eating, it has bulked up enough. It's time to push away from the table and go for a walk.  

Today, it only gave FDR a passing glance.

Stay tuned.

For the first photo with the same wooden ruler, click: Day 2.


Sunday, September 1, 2019

Day 12: simply beautiful

Metamorphosis Watch: Day 12

Simply a beautiful yellow, black and white striped nugget of nature and only one of many pieces from the whole, like a jigsaw puzzle. 
All have their place. 

The monarch butterfly caterpillar is shaped like a Japanese bullet train, but their speed is in growth. It has chunked up on milkweed for the transformation that is soon to come.

For a look back at its baby photo taken just ten days ago, click Day 2.


Saturday, August 31, 2019

Day 11: the appetite is back

Metamorphosis Watch: Day 11

Does it seem like FDR's smile has grown? He is watching an evolutionary miracle. The monarch butterfly caterpillar has returned to a day of eating. Its appetite appears to be back. At this rate, its final larval molt that leads to pupating is only a short time away.

“It’s estimated that in two weeks, the caterpillar will be 3,000 times larger than the day it hatches,” writes the National Wildlife Federation. 

We are getting there! Stay tuned.

Click for yesterday: Day 10.


Friday, August 30, 2019

Day 10: slow day

Metamorphosis Watch: Day 10

Waldo, the monarch butterfly caterpillar that we have had our eye on seemed sluggish today. The pace of its eating slowed. It may have molted, it has to four times to make room for new growth while the period between molts are called instars. 

Click for yesterday: Day 9. 


Thursday, August 29, 2019

Day 9: insatiable producer of frass

Metamorphosis Watch: Day 9

Three days ago, the monarch butterfly caterpillar was simply eating small holes out of the milkweed leaves, the caterpillar itself was hardly noticeably. Yesterday, it was chewing out entire sections and now it has grown to be an insatiable eater, it is working methodically on the entire leaf. 

Today, the caterpillar should be brimming with the cardiac glycosides that make it toxic to most birds. There are 14 species of milkweed native to Tennessee. Some are too toxic even for the monarch, some really do not contain enough of the glycosides but that leaves three species the migratory butterfly rely on: common milkweed (Asclepias syriaca), swamp milkweed (Asclepias incarnata) and butterfly weed (Asclepias tuberosa)  

FDR seems pleased by the progress. He liked to see things move forward in a positive way. Albeit with all that roughage, Waldo produces the inevitable poo, or to be more proper, with insect larvae it is called frass

Click for yesterday: Day 8. 

Wednesday, August 28, 2019

Day 8: what FDR has seen

Metamorphosis Watch: Day 8

One full week after the monarch butterfly caterpillar first crawled in front of the dime (below) and today FDR is looking at a distinctly larger larva. The leaves have changed but the dime has not. It's still worth ten cents.

We are at least five, probably six, days away from the beginning of one of the grandest evolutionary miracles in nature. Complete metamorphosis. One life form becomes another but retains its singular identity all the while. And then it has the lepidopteran wherewithall to fly to Mexico. 

Stay tuned. 

Click for Day 7.

Tuesday, August 27, 2019

Day 7: see-able Waldo

Metamorphosis Watch: Day 7

Only 24 hours have passed and the holes in the leaf—and Waldo moved on to a new leaf during the night—are much bigger and the 7-day-old monarch butterfly caterpillar is much larger as is its appetite. It will soon becomes ravenous. 

We're at a point where the monarch larva almost doubles its size every 48-hours making it much easier to see.

SPOILER: Nature is not always pretty. Being more see-able has a downside. Parasitic tachinid flies may land on the caterpillar and lay their own eggs. The resulting maggots burrow inside the monarch where they eat, develop and grow ultimately killing their living host. Gasp! 

Click for yesterday: Day 6.

Monday, August 26, 2019

Day 6: Where's Waldo?

Metamorphosis Watch: Day 6

Very young monarch butterfly caterpillars are hard to spot on a milkweed leaf. You often notice their handiwork first: lots of small holes. But that being said, when they are only a few days old, they are still difficult to find. But, it gets easier as the voracious young larvae continue to eat and grow daily as this one has since yesterday.

To see yesterday, click: Day 5

Sunday, August 25, 2019

Day 5: Bulking up

Metamorphosis Watch: Day 5

Just in case you are sitting on the edge of your seat wondering, our little monarch butterfly caterpillar that hatched four days ago, has now doubled in size since Friday. It is feeding exclusively on common milkweed (Asclepias syriaca). 

The bulk it puts on now will aid it in a few weeks during its flight to Cerro Pelón or one of the other Mexican mountaintop sanctuaries.

To see yesterday, click: Day 4