Wednesday, 1 February 2017

A Little More Nastiness From The Malevolent Designer?

Crypt-keeper wasp, Euderus set

Source: Rice University News & Media
Credit: Andrew Forbes/University of Iowa
Tales from the crypt: a parasitoid manipulates the behaviour of its parasite host | Proceedings of the Royal Society of London B: Biological Sciences

Sometimes the sheer malevolence of nature, if nature can have a personality, leaves one wondering what, if there could conceivably be some intelligence behind it, whatever sort of sadistic nastiness it could possible be that is so inventive in ways to be so hideously unpleasant. It beggars belief that there are not only people who believe this supposed intelligence is possessed by a real entity but that any entity this malevolent could be worthy of adulation, worship and praise.

The low-lives who breed dogs to put them in pits to fight to the death for the fun of it are paragons of virtue compared to any putative designer of nature given the hideous ways it seems to have found to entertain itself, all day and every day in millions of different ways.

It would be tempting to play a little game of finding the nastiest thing in 'creation' but so many examples abound in nature that it would be a never-ending task, and just when you think you have found the nastiest, up would pop an even nastier candidate. This example might not be the winner in such a contest but it would surely rate consideration. It is yet another example from the vast selection of grotesques to be found in the large family of parasitoid wasps.

This is yet another example of a parasite which turns its victim into a zombie that cooperates in its own destruction. In some ways there is a kind of poetic justice in that its an example of a parasite exploiting another parasite that also manipulates its host into cooperating, but the latter parasite only uses its host; it doesn't totally destroy it.

The crypt gall wasp, Bassettia pallida

Source: Rice University News & Media
Credit: Andrew Forbes/University of Iowa
Let's start at the beginning:

The crypt gall wasp, Bassettia pallida is a parasite on the sand live oak tree, Quercus geminata. Females of this wasp bore holes in the stems of this tree and lay individual eggs in the living wood. The presence of the egg induces the tree to grow a gall - a chamber in which the grub can live and develop, eating the inside of the gall, until it is ready to emerge into the outside world. When ready, it chews its way to the surface and emerges through the tunnel.

But, a few of these gall wasp grubs don't behave as normal; instead, they chew their way to the surface several months earlier, making a hole just large enough for their heads to fit in, then they wedge their head into it and stay there till they die.

They have been turned into zombies by the presence of the egg or grub of another parasitoid wasp, Euderus set. Having induced its host to prepare it's escape route for it, it sets about eating it from the inside. Once it is ready to emerge, it only need bore a small hole through the head of its former host. This neatly gets round the problem of not having strong enough jaws of its own with which to bore its way through the wood. It also means it can develop in the comparative safety of the gall it's host prepared earlier.

The crypt gall wasp Bassettia pallida infects sand live oaks, and induces the formation of ‘crypts’ in which the wasp will undergo development. Bassettia pallida infected by the crypt-keeper wasp Euderus set excavate small emergence holes that the host plugs with their head capsule prior to death. Euderus set emerges through the host's head capsule when it reaches its adult stage. (a) Adult B. pallida, (b) two dissected crypts containing adult B. pallida, (c) E. set pupa in a crypt made by B. pallida, (d) adult E. set, (e) emergence holes made by uninfected B. pallida, (f) emergence hole plugged by the head capsule of B. pallida, and (g) head-plugged hole with hole in B. pallida's head capsule where E. set emerged.
There are many examples of apparent manipulation of host phenotype by parasites, yet few examples of hypermanipulation—where a phenotype-manipulating parasite is itself manipulated by a parasite. Moreover, few studies confirm manipulation is occurring by quantifying whether the host's changed phenotype increases parasite fitness. Here we describe a novel case of hypermanipulation, in which the crypt gall wasp Bassettia pallida (a phenotypic manipulator of its tree host) is manipulated by the parasitoid crypt-keeper wasp Euderus set, and show that the host's changed behaviour increases parasitoid fitness. Bassettia pallida parasitizes sand live oaks and induces the formation of a ‘crypt’ within developing stems. When parasitized by E. set, B. pallida adults excavate an emergence hole in the crypt wall, plug the hole with their head and die. We show experimentally that this phenomenon benefits E. set, as E. set that need to excavate an emergence hole themselves are about three times more likely to die trapped in the crypt. In addition, we discuss museum and field data to explore the distribution of the crypt-keeping phenomena.

There are so many examples of the amoral mindlessness of evolution to be found in the world of parasites and parasitoids that it really would be impossible to chose the best (or is that worst?) example. In addition to the very many pathological microorganism such as bacteria, fungi and viruses, there are many more to be found in the round and flat worms, insects, especially beetles, flies and (often exquisitely malevolent and beautiful) wasps.

And yet trying to get a creationists, especially and intelligent (sic) design advocate, to discuss how they fit into a model which includes intelligence in the design process is near impossible. What I have never managed to do yet is to engage an intelligent (sic) design advocate in any meaningful discussion of how these example fit into a model which includes an benevolent designer!

The reason for this is probably all to obvious. It simply doesn't and can't be.

The whole host-parasite relationship would depend on any designer favouring either host or parasite and creating either the host for the purpose of being consumed by the parasite or creating the parasite to consume the host, and for what over-all purpose? The thrill of the chase? The enjoyment of watching suffering, maybe? All host-parasite relationships inevitably involve an arms race in which one seeks to outwit or counter the other in some way. Why would an intelligent designer design a host for the benefit of a parasite and then redesign the host to help it thwart its own plan? What possible ultimate purpose does that serve?

Host-parasite relationships are by their very nature amoral, uncaring and merciless - the very antithesis of benevolence. No intelligent designer who also wished to create a maximally good world would design parasites.

The world of parasitology forces intelligent (sic) design advocates to conceded that either their putative designer is not in fact intelligent and can't possibly be described as benevolent - or both. No wonder the best you are likely to get from them is some gibberish about 'The Fall' - as though making a crypt gall wasp suffer somehow pays back mankind because a remote ancestor was naughty once - some worthless rationalisation such as it not being for mankind to guess the mind of god. Either way they are forced to abandon the pretence that intelligent (sic) design is not religion but science, and Bible-literal fundamentalism at that.

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