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Caterpillar: A time of growth |
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See photos and slide shows illustrating complete metamorphosis of a monarch butterfly in transition from"Egg" "Caterpillar" "Chrysalis" to "adult butterfly" or click on the picture or texts below.
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| Look below for observations and slide shows showing caterpillar growth. Click on each thumbnail image to bring up a full size picture. |
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A time for growth has arrived. The larvae is driven by one commandnent in life." to eat and grow". In just two weeks the caterpillar will shed its skin five times. In other words, the insect must wear and outgrow five skins. Each skin is called an instar. All instars are shown in the photo slide show below. The first two photos in the full size sequence show the first instar phase. #3 shows the 2nd, #5 the 3rd, #6 the 4rth and #10 the 5th instar. Note photos 7-9 showing the shedding of instar #4 into instar #5. |
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A time for growth has arrived. The larvae is driven by one commandnent in life." to eat and grow". In just two weeks the caterpillar will shed its skin five times. In other words, the insect must wear and outgrow five skins. Each skin is called an instar. All instars are shown in the photo sequence. (Remember to click on the thumbnail photos to bring up a full size picture and start a detailed photo sequence slide show viewing.) |
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The caterpillar is only about ten days old. As can be observed the young larvae is in the process of its fourth shed. Close inspection will reveal a lighter yellow area just behind the head where the new skin is visable and the old skin has begun to split. Just after the shed the yellow head is visable. Notice how the old skin has been pushed back into a crumpled bit of debris which will soon be discarded. The new head and skin is much larger and will darken with time. |
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At this stage the caterpillar is eating its fill. It must get enough nutrition from a sole diet of milkweed leaves to fuel the complex processes of the metamorphosis to come. Now the larvae has grown to where the head size seems more in proportion to the body size. After this final leaf is consumed the larva will cease eating. Note: Monarch eggs and caterpillars are usually found on the underside of the milkweed leaf. This affords them protection from the sun, weather and some predators. This time of growth normally lasts from ten to fourteen days. |
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The larva has gone into what I call "wanderlust" mode. It moves about until it senses a secure spot in which to change into a chrysalis. (Remember to click on the thumbnail photos to bring up a full size picture and start a detailed photo sequence slide show. Viewing navigation is found under each photo.) |
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Now another chapter in this remarkable life cycle is at hand. "Preparaing for Pupation" Watch the animated slideshow below and look for the following highlights. After a day of searching and careful examination the larvae eventually settles down on a suitable area upon which it spends hours meticuliously preparing a silken anchor-hold. As time goes by the caterpillar feels ever increased promptings and restlessly moves about. Soon the movement assumes direction as the insect begins to crawl forward. During this phase the silk button is kept securily between the claspers. Once the caterpillar feels secure through repeated touch location of the silk button by its claspers, it quickly turns around and begins moving so that the posterior end comes in contact with the silk anchor. Watch carefully how the hind end bends forward to receive the "button". The hind end of the larvae has found and grabbed hold of the silk button. After establishing a firm foothold it is time to wait. Close observation reveals a faint greenish hue underneath the skin as the chrysalis begins to form underneath. Sporadic twiching and stretching is evident. At times a slight curve in the anterior portion hints at things to come. Signals from the chrysalis forming within compel the caterpillar to slowly begin releasing the claspers one at a time. Soon the larvae will completely let go. Its life is now completely dependent on the silk button and how well it has attached to it. As the insect assumes the "J" shape the pupal skin will continue forming. In about 12 hours from now the chrysalis will emerge. |
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This caterpillar is searching for a place to transform into a chrysalis. View this shockwave slide show. Just click on this picture.
View this shockwave slide show. Just click on this picture. |
Watch and observe closely as the caterpillar, having finished the "anchor", crawls forward till it feels the holdfast midway up its body, turns around, and proceeds to insert its hind claspers fimly into the silk "holdfast". The drama continues as gradually, clasper by clasper, the caterpillar lets itself drop. Now it is hanging in a "J" shape entirely dependent on the secure hold of the hind claspers. Note: This animated slide show is a good example of how hours of waitng, along with persistence, pays off. The time frame of the sequence below showing the caterpillar as it turns around to position itself in preparation for pupation happens within minutes. Leaving for a bathroom, snack or answering the phone may cause an event such as this to be missed. Hopefully, another caterpillar is available and one can try yet again to capture the moment. Of course, this applies for all the events shown on this website. |
| View more indepth "shockwave" picture presentations showing detail within a complete metamorphosis. Click on a link below. |
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Watch as a caterpillar is seen developing within its egg, hatches, and eats the egg shell. http://lifecycle.onenessbecomesus.com/egg_shows.html |
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See a caterpillar preparing for pupation. After a silk anchor is completed the larvae crawls forward midway, turns around, finds and securely attaches its hind claspers. Then the insect proceeds to slowly release and hang head downwards. http://lifecycle.onenessbecomesus.com/larva.html |
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A caterpillar to chrysalis transformation. The larvae sheds its skin to reveal a wet gyrating chrysalis. The pupae must transfer its hold to its cremaster and drop the old larval skin. The chrysalis gradually assumes its predestined shape and hardens into an imobile waxy pupae. http://lifecycle.onenessbecomesus.com/pupa.html |
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Chrysalis emergence as a transformed butterfly is indeed one of the wonders of nature. View a butterfly breaking free of the pupae, expanding and drying its wings. http://lifecycle.onenessbecomesus.com/adult_shows.html |
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About twelve hours later the old larval skin splits to reveal the soft moist chrysalis within. The shedding process is over in a couple minutes while chrysalis shape change is over in about five to ten minutes. Notice how the template of the future butterfly is clearly visible. |
| Click on a picture below to check out a 56 image digital photo sequence. This visual journal gives clear detail of the caterpillar transformation to a chrysalis. Each photo frequency time is 7 seconds. Navigation aids can be found under each image. The changing shape of the supple chrysalis is particularily well documented. Click on any picture to start the image sequencing at that point. |
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Be sure to click on all picture sets below to see a full size image and begin a detailed slideshow. Navigation links will appear under each picture. You can advance or go back at your leisure. |
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The soft helpless "prepupal" insect lets go and hangs in a "J" shap. At this point life is dependent on the grip of the two hind claspers into the silk anchor. The first of many challenges has been overcome. Now a time of waiting has arrived yet the internal workings of the larva are very active. The old caterpillar skin gradually appears ever-more wrinkled yet stretched. A hint of green from the pupa within is visible. The caterpillar-to-be-chrysalis jerks and stretches. Shriveled wilted larval whips are a sure sign the transformation is imminent. |
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The split begins from the bottom near the "head" and, within minutes, the now dead larval skin is moved upwards. The newly formed yet supple chrysalis exhibits "wavelike" contractions untill the skin is pushed to the point where the next acrobatic feat must ensue. (Remember clicking on the pictures will bring up a full size photo and start a full length slide show. You will see many more pictures than are visable here.) |
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It is now time for a feat few people are aware of but one which is commonplace in a world where fact is often stranger than fiction. The problem: The caterpillar has emerged from the old skin but it cannot be released because the hind claspers attached to the silk anchor are in the way. In other words a hind clasper of the catterpillar is attached along with the new chrysalis hook called a cremaster. Somehow, the cremaster must be extracted and reinserted into the chrysalis silk anchor while, at the same time, using the now dead caterpillar clasper as an anchor. This would seem to be a dilemna but the solution is far older than we have been around to address it. As seen in the photos, the pupa extracts the cremestar from the anchor and immediatly twists and turns to reinsert it firmly into the silk. Then, as the twisting continues, the clasper is relinquished and the skin falls away. Note: on a dry chrysalis the small black dots near the top are scars from the larval claspers. |
| Below is a close up sequence of the cremaster being being inserted into the silk hold-fast. The pupa twists its hook securly into the "button" after which the old skin drops away. Click on the photos to view full size and start a slideshow. |
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Now the change to a final form of the chrysalis continues. I say "continues" for this changing of shape began even while the caterpillar was shedding its skin. It can be seen from the pictures that the basic template of the chrysalis is evolving from the "caterpillar that once was" to the "butterfly that will be". The lower end where the head, mouthparts, eyes, thorax and wings will need additional room to form is elongating while the upper part containing the abdomen is shrinking. Over a few hours the change will be complete. In a day a soft very vulnerable ungainly looking chrysalis will be a thing of beauty. |
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Here is another digital image sequence of the caterpillar-prepupal-chrysalis transformation. The set frequency is 10 sec. Chrysalis images are of better quality. The wet glossy highly reflective moving chrysalis makes lighting a real challenge. |  |
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Three main events are going on here: The splitting of the larval skin, disposal of the larval skin and the changing of the chrysalis shape as it dries and hardens. Click on any picture to start a session at that point. |  |
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| For contrast here is a video quick look at a cecropia moth at the same stage of its life cycle as the monarch butterflly. Compare the prepupal and pupa formation stage of the cecropia with the monarch. How are they different and similar? How are moths different than butterflies in this regard? |
| Experiance and learn how life is indeed a set of thematic variations. View cecropia metamorphosis from egg, caterpillar to spinning the cocoon and prepupa to pupa transition. Just click on the cecropia caterpillar below. |
| This very different caterpillar is the larvae of the cecropia moth. This large moth is very different from monarch butterflies. Instead of migrating south, cecropias, and most other species of butterflies and moths, spend the winter in the pupal state. Cecropias have only one brood a year. Just one generation is seen each summer. All will overwinter in a cocoon. This website now includes both Hyalophora cecropia and Antheraea polyphemus saturniid moth life cycles. Click navigation tabs or simply click on the caterpillar to the right. |  |
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A couple questions |
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The left photo shows what is apparently a different color morph of a monarch butterfly larvae. Notice the greatly increased black banding and reduced white pattern compared to the normal caterpillar below. Both of these larvae came in with an order of live caterpillars from Texas. All of the individuals eventually died of a bacterial infection. Note: All other monarchs shown on this site were collected and reared by myself. I was just impatient. This was a very late season for monarchs to finally appear in Kentucky. The first one I spotted was August 10th 2008. |
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A question arises whether there are five or six instars. Notice the difference in the coloration of the caterpillar shown in photos 1 & 2 in the first sequence above. does this represent two different instars (which would make six total)? If one looks closely it is evident the 2 day old larvae in photo #4 has a very small head where a large head to body size is found in a new instar phase. Link to the question above to find out more on this issue. |
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New indepth digital slideshows are to be found on each page. The complete metamorphosis lifecycle is presented as a multiple series of indepth digital images. Don't miss out. Be sure to scroll down each 
