Nature Notes – From the Backyard to the Biosphere. Our Lepidopteran Friends

Now that summer is truly here, and the oppressive heat has taken over from the frigid cold as our preferred focus of complaint, it is time to discuss one of summer’s unique treasures: the butterfly. Rare in the insect world for engendering among humans a love for its aesthetic qualities, the butterfly is admired for its grace, its colour, its form, and its habit of gaining a livelihood from another natural favourite: flowers. But butterflies offer more than beauty to dazzle the human senses. Beyond their superficial loveliness lies an evolutionary path so circuitous and complex that one cannot help but gape in awe at the spectacular mastery present in natural design.

Where to begin: the butterfly or the egg? Let’s start with the little egg: Laid on a plant that will likely form its sole diet upon hatching, the young soon emerges from the egg phase into what many would consider the butterfly’s less glamorous stage: that of the creepy crawly caterpillar. Covered in fluff, graced with a plethora of stubby legs, and equipped with mandibles ready for grasping, tearing and chewing, the butterfly’s adolescent version is made to eat. The young caterpillar is likely to find itself going it alone on a food plant, deposited there by a mother careful to minimise competition and ensure that her young are provided with sufficient food resources for growth.

The frustrated gardener will no doubt scoff at this description of motherly care, remembering instead the holed plants of previous summers, and the little chompers that undoubtedly constituted the culprits. But a single caterpillar will in fact do very little harm to its host plant beyond aesthetic damage, so the wise garden steward will not dust or spray, but will instead remove by hand these solitary fuzzies, placing them on the less prized, or less visible of the caterpillar’s favoured plants.

It must be remembered that without this essential eating and growing stage, there can be no butterfly to grace the garden with its loveliness. So lovely, too, must we consider the caterpillar and its gastronomic needs. Eating its way through succulent plant parts, the caterpillar grows in size and complexity, transforming internally in a manner unbeknownst to all but the creature itself. Beneath the comical, spiked exterior a sophisticated physiological process is occurring in which the caterpillar molts between increasingly developed larval stages known as instars. Internal wings begin to form, and the stage is set for the caterpillar’s future existence as an adult butterfly. But there is no sign of such latent development in the still fuzzy, still hungry young caterpillar.

The next stage of the development process is possibly the strangest, and constitutes a complete alteration in the creature’s physical form. The caterpillar’s silk glands finally rise to their full potential, as the insect spins around itself a thick silken cocoon. Inside of this chrysalis the insect will undergo a process described most unattractively as self-digestion, or most pleasingly as metamorphosis. Attached to a stem or the underside of a leaf, the insect will remain in the pupal stage for one to two weeks. During this time its wings will fully develop, its mandibles, or lower jaws, will essentially disappear, and its maxilla (upper jaw) will transform into the curled, sucking proboscis the adult uses to drink from flowers. The completely metamorphosed creature will emerge from the pupal molt as an adult butterfly.

For the first time, this emergent adult will open its wings, still delicate and crumpled, and not yet flight-worthy; these four transparent membranes covered in a tapestry of coloured scales will allow the butterfly to carry out one of its most important evolutionary functions: dispersal. The newly-sprung butterfly must take its time entering the world in this form, pumping its wings full of fluid, and warming itself in the sun for what will be its first aerial experience. When sufficiently warmed and primed for flight, the butterfly will leave its host plant, and for the first time venture off as an adult in search of food, home and mate.

This is the stage at which we must truly appreciate the butterfly, second only to bees in facilitating plant pollination. Lured to meadows and gardens by the scent, colour and form of the flowers contained therein, a butterfly will unfurl its curled proboscis, and, like a child with a straw, drink the flower’s sweet, nourishing nectar. That its body and legs become the vehicle for pollen transfer from one flower to another may little influence the butterfly’s thoughts and musings. But such well-orchestrated activities suggest the butterfly’s role as not only a gardener’s decorative delight, but rather as an astounding example of evolutionary development, and an essential piece in the ecological puzzle.

Zoe Dalton is a graduate of York University’s environmental science program, and is currently enjoying working towards a Master of Arts in Integrated Studies with Athabasca U. She can be reached for comments or questions at zk_dalton@hotmail.com.

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