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Carroll Williams: experiments on the metamorphosis of butterflies

DrWatson's profile picture
Published in 
Phasmatodea
 · 14 May 2021
35

The birth of a butterfly

The metamorphosis of the caterpillar into a butterfly is one of the most common biological phenomena. From an egg laid by the butterfly, a small caterpillar hatches which nourishes truthfully for 6-8 weeks, until maturity; it is then a fat worm of about 8 cm. The larva then spins the cocoon, inside which it turns into a pupa. During a period of hibernation the pupa's body is somehow rearranged to form a mature moth that will find a mate and repeat the cycle. But what causes this incredible body change? What mechanism controls the chronology of these phenomena so that the fragile moth leaves its cocoon only in the warmth of spring? Over the past two decades, some elegant experiments have helped to shed light on the mystery.

Carroll Williams: experiments on the metamorphosis of butterflies
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From egg to pupa: story of a Cecropia. An egg hatches after 10 days (1). The caterpillar, which has turned green to blend in with the substrate, grows enormously and changes 4 times (2). Spin a cocoon with liquid silk secreted by buccal glands (3). In 4, 5, 6 the transformations of a pupa within the cocoon which here has been removed for a clear vision.

Carroll Williams: experiments on the metamorphosis of butterflies
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The butterfly comes out of its papal envelope, which begins to split on the side of the head; then, with the help of its legs, the insect gets rid of the envelope completely and shows its folded wings. In short, the butterfly can fly and becomes a machine destined for reproduction, which lives only to find a mate to mate with.

Carroll Williams

In 1942 the biologist Carroll Williams began a series of brilliant experiments that led to the solution of the mystery of metamorphosis. Working on cecropia, Williams soon realised that what directed the phenomenon of metamorphosis was located in the front of the insect. If a pupa was cut into two parts, the front half developed into a half butterfly while the back remained pupa. Williams also found that the cause of the change was located in the head. The experiments of the scientist, some of which are presented here, revealed two independent hormone-producing centers: one in the brain, the other in the chest, just behind the head.

Further experiments showed that an increase of the temperature stimulates the flow of the brain hormone and also initiates the wonderful transformation that occurs in the hibernating moth.

Carroll Williams: experiments on the metamorphosis of butterflies
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A caterpillar can develop even without hormones. To prove this fact, Williams separated the head from the thorax and then the thorax from the tail with a tight ligature.
With these separations the caterpillar continued to live but without metamorphosing.

Carroll Williams: experiments on the metamorphosis of butterflies
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With a hormone, development begins. The ligation in the insect was performed after the brain hormone entered the circulation, but before the thoracic hormone was produced. The thorax has developed, but the same cannot be said of the tail.

Carroll Williams: experiments on the metamorphosis of butterflies
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With both hormones metamorphosis occurred. The head and chest were separated with a ligature after the hormones were produced. Experiments show that cephalic hormone stimulates thoracic hormone and metamorphosis.

A decapitated female develops to mutate and lay an egg.
When hormone-producing centers are introduced into the adult pupa whose nipped end is covered with plastic, the abdomen develops into the posterior part of an adult butterfly.

Carroll Williams: experiments on the metamorphosis of butterflies
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This female fragment attracted a male, was fertilized and laid numerous eggs (picture below).

Carroll Williams: experiments on the metamorphosis of butterflies
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By dividing the pupae in half, the effect of the lesions on the metamorphosis can be checked. For a comparative examination Williams used four butterfly pupae of the same age. From left to right: a whole pupa, a divided pupa, whose two cutting surfaces are covered with plastic, a divided pupa but then joined by a tube, and finally a divided pupa with the two halves joined by a tube in which a movable ball can stop any tissue that grows and attempts to rejoin the two segments.

Carroll Williams: experiments on the metamorphosis of butterflies
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A month later the experiment ended. The first pupa develops normally; the second has a metamorphosed front part and not the back; the third presents a reunion of the pieces by means of a cord of tissue that has grown into the tube and through which the hormones can pass. Both extremities developed. The fourth pupa, in which the movement of the ball prevented tissue growth, did not develop. Williams concluded from these experiments that wounds must heal before metamorphosis.

Carroll Williams: experiments on the metamorphosis of butterflies
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A fatal flight concluded the experiment. The third pupa, which has become a butterfly, extends its wings and flies away. Although the two sections of the body had developed, the delicate fabric bridge within the tube broke and the insect fell to the ground and died.

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Comments

35
guest's profile picture
@guest

Absolutely amazing! I did not know it was possible to cut a pupa in half and still have it became a butterfly. Nature is wonderful and amazes us each day

21 Feb 2024
guest's profile picture
@guest

ㄷㄷㄷㄷ

10 May 2024
guest's profile picture
@guest

무섭다

11 May 2024
guest's profile picture
@guest

It’s kinda scary though

15 May 2024
guest's profile picture
@guest

오우

15 May 2024
guest's profile picture
@guest

it's a very bizarre experiment

15 May 2024
guest's profile picture
@guest

불쌍한 나비

17 May 2024
guest's profile picture
@guest

외계인이 사람을 잡아다 상체와 하체를 자르고 요상한 관으로 이어놓고 살려둔 뒤 한 걸음 걷는 순간 그 관이 떨어져 죽게 만든다고 생각을 하니 호달달달 쥰나게 무서워졌다

17 May 2024
guest's profile picture
@guest

너무 불쌍해 ㅠㅠ

17 May 2024
guest's profile picture
@guest

그렇게 징그럽진 않네… 근데 나비 불쌍해ㅠㅠ

17 May 2024
DrWatson's profile picture
@DrWatson

Very funny that I needed to translate the previous comments to understand them 😊 My article is very popular abroad 🥰 It seems like everyone feels sorry for the poor butterfly. I agree with you: it doesn't justify mistreating other living beings 🥹

17 May 2024
guest's profile picture
@guest

오우쉤

18 May 2024
DrWatson's profile picture
@DrWatson

Ohh ... another comment 😁 My article is becoming very popular 😃

18 May 2024
guest's profile picture
@guest

무서위

21 May 2024
guest's profile picture
@guest

개체에서 추출한 액체를 다른개체의 번데기로 주사하면 자이언트 나방이 되지 않을까??

22 May 2024
guest's profile picture
@guest

은잡지님 영상 보고 왔어요!
정말 놀랍고 신기하지만, 곤충 입장에서 생각하면 극심히 두려워지네요ㅠㅠㅠㅜ잘 자라다가 별안간 납치당한 것만 해도 무서운데 내 몸을 두 동강 내고 이물질을 끼워넣곤 그대로 자라자마자 죽게 만들다니... 인간은 잔인해....ㅜㅜㅜ

23 May 2024
guest's profile picture
@guest

엄....

23 May 2024
guest's profile picture
@guest

oh my gosh

23 May 2024
guest's profile picture
@guest

대단한 연구다 신기하다

23 May 2024
guest's profile picture
@guest

은잡지 영상 보고 왔어요 어...........어음......

24 May 2024
guest's profile picture
@guest

은잡지로 왔는데 이게머냐 마너지는 어딨어

24 May 2024
DrWatson's profile picture
@DrWatson

Unfortunately I don't understand your language 😆 I used an online translator, according to which it seems like you are talking about a magazine. What magazine are you referring to?

24 May 2024
guest's profile picture
@guest

은잡지님의 영상보고 왔어요!!
실제사진 보니까 겁나 신기하다

25 May 2024
guest's profile picture
@guest

A Korean YouTuber called "은근한 잡다한 지식" introduced your experiment. "은잡지" is an acronym for his channel name. I'm not sure why people seem to have visited your article recently, since the video was uploaded more than a year ago.

25 May 2024
DrWatson's profile picture
@DrWatson

I wasn't aware of it as I don't understand the Korean language. Thank you very much. I think I've found it 😊

25 May 2024
guest's profile picture
@guest

금사향 번데기

26 May 2024
guest's profile picture
@guest

실험이니까 어떻게할수도없고 너무불쌍하면서신기해

1 Jun 2024
guest's profile picture
@guest

소름돋았어!

1 Jun 2024
guest's profile picture
@guest

다음엔 다른것은 좀...........

1 Jun 2024
guest's profile picture
@guest

살면서 본 실험중에 가장 큰 충격이다.

1 Jun 2024
guest's profile picture
@guest

ㄷㄷㄷㄷㄷ

2 Jun 2024
guest's profile picture
@guest

띠바 저게 뭐노?

2 Jun 2024
guest's profile picture
@guest

충격은 둘째치고 귀여운 나비가 흉측하게 생겼노.....

2 Jun 2024
guest's profile picture
@guest

어허이~엄청나 굉장해!

6 Jun 2024
guest's profile picture
@guest

오마이 갓 래전드

9 Jun 2024
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