Stranger Than Fiction
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Anyone care to guess what this is?
It’s a caterpillar, obviously, but what species? Believe it or not, this rather weird looking wormlike creature will someday metamorphose into this.
It is a larval stage of a Pipevine Swallowtail Butterfly. If one didn’t know beforehand, who could imagine the incredible changes that the mundane caterpillar will undergo in order to become a magnificent butterfly?
And, indeed, those changes are spectacular. The caterpillar is so different from the adult as almost to constitute a totally different life form. Consider this: caterpillars survive and grow by eating leaves. Adult butterflies, by contrast, lack the ability to consume solid food, they survive exclusively on liquid diets. And, that’s just one of the myriad differences between larval butterflies and adults.
The ingenuity of nature — benefitting from hundreds of millions of years of evolution — is seemingly boundless. Butterfly caterpillars exist for only one purpose and that is to acquire enough nutrients and calories to be able to make the transition to adulthood. They are essentially digestive tracts with legs. If given the chance a caterpillar will eat continuously from the time it hatches from an egg to the moment it becomes a pupa. Moreover, caterpillars change their form and their appearance as they grow. Typically, a butterfly caterpillar sheds its skin (molts) a few times during its existence and it’s quite common for each stage (instar) between molts to be not only larger than its predecessor, but to have a somewhat different appearance.
This is also a Pipevine Swallowtail caterpillar, but nearly twice the size of the one shown above. It is a later instar, I believe, and its appearance is similar to, but not identical to, that of the earlier instar.
What accounts for the unique appearance of these caterpillars is a good question. I have no idea what function the various protrusions and bumps on the caterpillars fulfill, if any, and I really can’t explain these caterpillars’ rather bizarre color combinations. Every species of butterfly, however, produces its own unique caterpillar, and some of them are truly amazing looking. And, as obvious, the caterpillars bear no similarity in appearance to the adults.
But, as amazing as these growth stages are, they are but nothing compared to what happens when the caterpillar makes the final jump to adulthood. I’ve described this process before, but its worth repeating. The caterpillar forms an outer shell (chrysalis). Within that shell, the caterpillar dissolves. Its body literally turns to liquid — a nutrient soup. However, clumps of specialized cells (imaginal discs) within the caterpillar’s body remain intact. And, from these imaginal discs grow all of the organs and structures of the adult butterfly. It is literally a case of death and reincarnation.
So, next time you see a butterfly — or a lowly caterpillar — stop and think for a moment. Is their anything more extraordinary and ingenious in nature than the process that resulted in that butterfly?
Images made with a Canon 5DS-R, 180 f3.5L Macro Lens assisted by Canon 600EX-RT Speedlite, M setting. Images of the caterpillars were made at ISO 200, f14 @ 1/160. The image of the adult butterfly was made at ISO 125, f11 @ 1/160.