Metamorphosis

By Boak Wiesner

Coming east into the Arboretum, a Sandhill Crane flew over my head and the topic for this entry came to mind: changes, especially metamorphosis. Being outside for any length of time these days is, for the most part, to experience major transitions: the return of the birds and butterflies back from the South, the breathtakingly rapid changes in the weather, the emergence of spring’s first flowers.

Not so very long ago, cranes were rarely seen around these parts but now can be found all over. I heard them this morning through the bedroom window! Bald Eagles, Trumpeter Swans, Osprey, Wood Ducks, beavers: all these have come back from minimal populations over the last several decades, despite more and more people moving into the area. Things do change for the better over long periods of time.

While many butterflies migrate back from the south like birds, some like the Mourning Cloak overwinter here as adults and so are ready to fly again during the first warm spell. Red Admirals, whose caterpillars can be found later on Stinging Nettles in moister areas, are all over nectaring on plum blossoms. Spring Azures and Whites flit around. It’s a good way to practice your moving binocular skills to keep them in view.

When one has occasion to think of things that are truly near-miraculous in nature, take as a prime example the metamorphosis of butterflies: An egg is laid.  A caterpillar hatches. Several sheddings occur as each instar outgrows its former skin. (Since insects are arthropods, like crayfish, their exoskeletons don’t enlarge once formed, so to get larger, caterpillars have to crack out of their old skins and expand into new ones.) Then consider pupation. Really stop and think about it: the larva’s final skin splits open and the next “skin” down underneath forms the chrysalis. Then inside of that, the pupa digests up all of its former self and, using the same biomolecules already in there, resynthesizes them into the wings, legs, proboscis, eyes, antennae – all of the parts of the adult butterfly. Imagine! Then out it pops, pumps “juice” from its big abdomen into the veins of its wings, lets them dry a bit, and flies away! And, think of it!, the great-grandchildren (at least) of last season’s Monarchs will migrate all the way back to the middle of Mexico come fall!

One of the first wildflowers to appear in the spring is the Bloodroot, named for the sticky, burning, red latex that oozes from the rhizomes when they’re cut open. The products of last year’s photosynthesis have been stored in the rhizomes so the plants, like pupae, digest the carbohydrates and use the smaller pieces to synthesize the new new leaves and flowers. Bloodroot blossoms have no nectar and hardly any smell, yet bees come to them anyway – they’re the only game in town!

As is typical for me, some Aldo Leopold comes to mind: “The months of the year, from January up to June, are a geometric progression in the abundance of distractions.” As well as natural phenology to witness and write about.

 

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