Any member of the very large insect family Ichneumonidae, of which an estimated 100,000 species exist world-wide. Its horrific manner of breeding once shook the foundations of Christianity.

The standard Ichneumon wasp has two pairs of veiny wings and an ovipositor on the abdomen for breeding. However, there is great variation within the family. Some wasps have a short one, but the Rhyssa persuasoria needs an especailly long organ so that it can drill through wood to lay its eggs in the larvae of the Wood wasp. Other species need to dive underwater to find their larvae, and still others are wingless, and place their eggs inside spider eggs.

In earlier centuries, some Christian philosophers believed that since animals do not have souls, they must have been placed on this earth to provide spiritual direction to man, their master. Thus, by observing the lion, we would learn God s lesson on true pride, and by watching an anthill, we can pick up a few things about cooperation. With some animals, such as the rat, it was a little trickier to figure out the lesson, but a kluge was usually found, (Maybe they taught us to live in clean conditions). This theory was an impetus for the church to direct more of its efforts into zoology, so that more animals could be found for us to project our egos onto.

A bit of a conundrum was found when our biotheologists first recorded the breeding habits of the average Ichneumon:

  1. The wasp finds a nice fat caterpillar, and stings it. This does not kill the bug, but paralyzes it.
  2. She lays her eggs in the body of the caterpillar, and flies off.
  3. After a few days, the wasp eggs begin to hatch inside the bug.
  4. The wasp larvae begin to eat the caterpillar's flesh for nourishment. But they don't just go around eating everything willy-nilly. If they kill the bug, the flesh will start to decay. So they start with the fat cells.
  5. Once they've eaten the fat, they move on to the muscle.
  6. Once they've eaten the muscle, they move on to other non-vital organs.
  7. Once they've eaten the non-vital organs, they finally eat something the bug needs to survive, like the heart, and put the caterpillar out of its mercy.
This process takes about two days. The caterpillar can be observed twitching in pain the whole time.

So, what is the message to us from our just and loving God? Theologans were quick to offer bad suggestions. Some thought it was a demonstration of the original sin of the caterpillar, which would grow up into a pest. Others suggested that maybe the agony of the insect could be likened to the ecstasy of martyrdom of the saints. Still others believed that it was a preview of the punishment that sinners could expect in hell. Nobody was really all that convinced. In the end, someone suggested that maybe the message was that nature is cruel, and that some animals just don't carry any message at all.

These days, we know too much about nature to make that mistake again. The lion has been unmasked as a scavenging bully, and the anthill is more an example of emergent design from chaos than any real central planning. The ichneuman wasp serves as a warning against projecting our own emotions onto creatures that lack the slightest shred of human compassion.

Thanks to insect-world.com for the taxonomy, and to Hen's Teeth and Horse's Toes by Stephen Jay Gould for the historical context.

Hymenoepimecis is a member of the Ichneumon family with remarkable breeding characteristics. It follows the same basic visual makeup of the average Ichneumon with the characteristic veiny wings and ovipositor. The thing that separates this species from all the others in its family is the fine degree to which it controls its host. Here"s the way it goes about reproducing:

  1. The wasp finds a special orb spider, Plesiometa argyra, and stings it. The sting paralyzes the spider just long enough for the wasp to lay its egg inside of it.
  2. The spider wakes up with a headache and some stomach pain, but continues function normally.
  3. Around 7-14 days pass, during which the larva is gestating and developing. The orb spider is still building its web and capturing prey.
  4. During its last day in existence, the spider weaves a completely and totally different nest- a cocoon web for the wasp. A normal orb spider"s web is intricate and beautiful; it has a complex system of supports and a specialized sticky pattern of rings used to trap prey. The web it spins for the wasp, though, is completely different. It has four supports and they come together at a miniscule four-cornered web with a single thick strand dropping down from its center. From that strand, the wasp"s thick oblong woven cocoon hangs.
  5. As soon as the spider finishes weaving the wasp"s creation, the wasp emerges from the spider, eats it alive, and suspends itself from its newly woven cocoon. The cocoon provides two main benefits for the wasp: protection from rain and protection from predators.

According to the biologist who discovered Hymenoepimecis, fast acting chemicals egested by the larva induce these changes in the behavior of the spider. Let me repeat that again for clarity: This small insect can control an arachnid using complex chemicals, and it can do this before birth!

To me, this is simply the most amazing thing about the natural world.

Source: http://www.museums.org.za/bio/spiderweb/manip_wasp.htm

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