Lessons from a Wasp

Ichneumonid Wasp, photographed at 5:00 am on May 4 in Lunenburg County, Nova Scotia

Could a small wasp expand my vocabulary? Reveal secrets of biology? I woke particularly early one day and found this beauty buzzing around my kitchen. I caught the wasp, photographed and released her–all in a matter of minutes. Then I began to investigate.

What I learned is: the Ichneumonid is a common reddish-brown wasp, with a slender 1 1/2 inch body, long antennae, and a curved ovipositor. It uses its ovipositor to lay eggs in the bodies of spiders, caterpillars and various grubs. The wasp is useful to people as it controls pests on crops.

Continuing my research, I encountered three words that were unfamiliar to me. Each word is connected to different aspects of ecology.

  1. crepuscular, pertaining to twilight or dawn. In biology, it refers to an animal who is most active at those times of day when its not fully night and not quite day. The Ichneumonid wasp is crepuscular, attracted to the lights of buildings on the edges of fields or forests.
  2. protelean. In biology, this usually refers to an insect that is a parasite in an early larval stage of life, but is not a parasite in an adult stage of life. The Ichneumonid wasp inserts its egg inside another insect. As the wasp larvae hatches, it consumes and destroys its host, eventually emerging as a winged adult that now feeds mainly on the nectar of flowers. The word protelean comes from Proteus, a Greek sea god who has the power to change shape, size and appearance.
  3. holometabolous. In biology, the word is often used in conjuncture with metamorphosis. A holometabolous insect is one who undergoes four complete stages of metamorphosis: egg, larva, pupa, adult.

This word exercise led to a curious stream of thought. First, I wondered if these were merely technical words used by biologists and no one else. For instance, could the words be used in other contexts? Had someone like Shakespeare ever used them? For example, I found this sentence in a review of an opera based on Midsummer Night’s Dream: “It was a moment of pure magic and set the seal on an opera that shows [Benjamin] Britten not only responding to Shakespeare, but revealing, in a way few straight productions do, the play’s crepuscular strangeness.” (Michael Billington, “A Midsummer Night’s Dream: Shakespeare’s Great Shapeshifter,” The Guardian, Aug. 12, 2016)

About the metamorphosis of an insect, I pondered how an insect could live one part of its life as a parasite and another part of its life as a symbiont living in close cooperation with another living entity. For example, a caterpillar eats the leaves of a tree. Yet as soon as the caterpillar becomes a butterfly, it now becomes a pollinator of the flowers of trees. One stage of life, it’s destructive; another stage of life, it’s helpful.

What is the advantage of metamorphosis for insects? Why did they evolve such radical changes to their bodies? Science writer Ferris Jabr suggests three answers: 1) As the young insect has a different diet and occupies a different ecological niche than the adult insect, young and old are never in competition with one another. 2) Metamorphosis is a survival strategy. If food were to get scarce, the insect could survive for extended periods in the semi-dormant pupa stage. 3) If an insect lays multiple eggs, it might be difficult for the parent insect to provide sufficient nutrients in each egg to bring the embryo to full term. However if the nymph hatches prematurely and learns to feed itself, using resources outside the egg, than this frees the energy demands on the parent. (Scientific American, Aug 10, 2012)

In this discussion, it’s worth noting that Insects are not alone in experiencing metamorphosis. Sea creatures like sponges and jellyfish also change their bodies in remarkable ways. These changes often involve a transformation from a fixed or rooted, filter-feeding creature to a mobile hunting creature. Nutrient resources change, energy requirements change, body shapes change.

These answers, while reasonable enough, omit one important area, how insects interact with bacteria. A radical mid-life change in diet might require the insect not only to change their bodies, but also to alter the bacteria inside them, particularly the bacteria in their guts. New bacteria support new functions. Could we say that these strategies (niche swapping, bacterial renewal) promote biodiversity both inside the wasp and in the environment around it?

In conclusion, a wasp taught me three new words. The words touch on aspects of animal behaviour, physiology, adaptation, and ecological relationships. All of which led to a greater appreciation of the wasp’s twilight crepuscular protelean shape-shifting world that encourages diversity and reinvention .