Hymenopimecis sphecidae

This is lightly paraphrased from the BBC's report on an article in Nature. I'd be interested to see anyone explain this in terms of evolution or natural selection...

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The larva of the parasitic wasp Hymenopimecis sp. will eventually eat its host spider - but not before it has injected a behaviour-bending chemical that makes the spider construct a special scaffold. This design, which is quite different from the spider's normal fly-trap, has the strength to support the pupating wasp.

The spider, Plesiometa argyra, is doomed from the moment it is stung in the mouth by the adult female wasp. This paralyses the spider and allows the wasp to lay an egg on the arachnid's abdomen. When the spider recovers it goes about its daily business of web weaving and feeding, unaware that it has become a meal for the developing larva now hatched and clinging to its body.

The larva will make small holes in the spider's abdomen through which it can suck the creature's haemolymph, a task made easier by the apparent introduction of an anti-coagulant that prevents the circulatory fluid from clotting too quickly. When this blood does eventually clot, it makes a large scab that acts as a saddle from which the larva can hang and reach for its next meal.

Finally, on the evening of the day that it will kill the spider, the larva induces the spider to spin this unusual web from which it will hang its cocoon. The design is unique - the spider will not build anything similar during its normal life. When the wasp somehow senses that the construction is finished, it will kill and start to eat the spider. This happens more or less at midnight and lasts until about midday.

It will then drop the spider's empty body to the ground and sit in this special web until the next evening when it begins to build a cocoon.

Your problem here is not a lack in evolution, it's a lack in your understanding of the word. This system could have been created through evolution - what you fail to see is what evolution is.

Evolution as you're referring to it is the gradual changing of species through natural selection. Those individuals who survive can go on to create a second generation of individuals. These individuals will have attributes more similar to those who survived the previous generation, and will grow up and possibly mate, possibly die (understand that for the purpose of evolution, if you don't mate, you're dead). If we introduce some variable into here, say, a fast predator, those who survive one generation will be those who produce offspring. The offspring will be more like the surviving previous generation, ie, they will be able to run fast. Of this generation, the slower ones will be weeded out and killed, and the faster ones will mate, etc, etc. On the other hand, if the predator is really fast, chances are that the species we are observing here are doomed from the start. None will survive, none will produce offspring, and there will be no evolved response to the predator. If any do survive, they won't survive because they could escape, they would survive because they simply were not affected - the predator now becomes a random event - and there will again be no evolved response to the predator.

In the case of the wasp and the spider you outlined above, all off the affected spiders (read "those killed by the really fast predator") will die. Those who are not stung by the wasp (these are not the fastest, they are the ones who have never seen the wasp) will survive and produce offspring who know nothing of the wasp. What this means is that the only possible evolved response is increased avoidance of the wasp - there's no way there could be an evolved immunity - and since the wasp is probably very hard to avoid, we can assume that the event is random, therefore the spider cannot evolve out of this system.

What I'm less sure about though is how the wasp could have evolved into the system - I can come up with a route along which it could follow, but, like the route between bacteria and groups of cells into specialised cells grown from a single egg, they seem pretty unlikely. Ah well, such is life...

This node was created in support of creationism. Its creator is suggesting that this behavior may be too complex to be the result of blind evolution, but must be the result of intelligent design.

It needs to be said: if this is the product of intelligent design, then the designer is one very sick and twisted individual. I'd rather accept evolution than believe in a god quite that demented.

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Yes, I am judging God by my puny mortal standards. How else am I supposed to judge God? If god didn't want me to judge God so, why did God make me this way? I insist on my right to Judge god, and to do so by the standards with which I am endowed, supposedly by god.