Wednesday, 12 May 2021

Unintelligent Designer News - Overcoming the Defences It Designed

Horseradish flea beetle: Protected with the weapons of its food plant | MPI CE

One of the more idiotic aspects of intelligent [sic] design Creationism is the way its advocates ignore the evidence that for there to have been a single sentient designer (as required by the central dogmas of Christianity and Islam), this designer would have to be incredibly stupid or amnesiac.

As research like this shows, there are very many cases in nature of a defence being 'designed' then a workaround for that defence also being designed in a predator or parasite, as though the 'designer' treated its solution for one species as a problem to be overcome - a problem of its own creation!

Quite simply, this is not an intelligent act. Nor is it a characteristic of good design, let alone intelligent design.

However, it is a predictable outcome for a mindless, undirected, natural process like evolution, where the randomly mutating genes will be naturally selected for whichever mutation results in the most copies of themselves appearing in the next generation, with no concern for the genes of another species. Hence, we have abundant examples of arms races in nature and arms races are themselves a major driver of evolution.

The predictable result of one such arms race, for example, is that plants will tend to evolve toxic defences against species that eat them. This is the classic example that gave us mustard, for example. And of course, it's entirely predictable that species that eat plants will evolve ways to avoid being poisoned by these toxins, otherwise they will quickly run out of food or have to continually evolve ways to exploit other plants as a food source.
As I said in Chapter 3 (Arms Races) of my popular book, The Unintelligent Designer: Refuting the Intelligent Design Hoax:
Repeatedly having to find work–arounds for problems created as solutions to other problems it created earlier is the antithesis of intelligent action. It looks exactly like two species adapting to environmental change by genetic evolution without any planning or ultimate objective and simply building layers of increasing complexity in order to stand still, to the ultimate benefit of neither and with increasing costs to both.
Here then we have yet another example of one such arms race, involving a commercially important crop and an economically important pest. The crop is the horseradish, Armoracia rusticana, a plant of the Brassicaceae family and the horseradish flea beetle, Phyllotreta armoraciae.
A team of scientists based at the Max Planck Institute for Chemical Ecology, Jena, Germany, have worked out how these beetles accumulate the mustard oil glucosides inside their bodies and thereby make themself distasteful or toxic to species which might be tempted to eat them - in this case, a species of ladybird. Incidentally, note here the inevitable 'altruism' involved, in that a potential predator will need to experience eating one or more of these beetles before it learns to avoid them. This strategy means more of the genes for accumulating these toxins will appear in the next generation, at the expense of a few of those carriers in this generation.

As the Max Planck Institute for Chemical Ecology news release explains:
We found 1401 putative membrane transporters in the gut and excretory system of this beetle. Narrowing down our search to transporters that are specific for the horseradish flea beetle helped us to identify a group of glucosinolate-specific transporters.

Sequestration is probably one of the most complex adaptations that herbivorous insects have evolved. It most certainly also contributes to the evolutionary success of insects that specialize in certain host plants, such as the horseradish flea beetle

Franziska Beran, Lead author
Research Group Sequestration and Detoxification in Insects,
Max Planck Institute for Chemical Ecology, Jena, Germany
Although it has long been known that horseradish flea beetles and related species can accumulate glucosinolates, how the beetle absorb and store high amounts of these substances in the body was unknown. The research team's goal, therefore, was to identify glucosinolate transporters in this insect. "The search for these transporters was literally like looking for a needle in a haystack," recalls Beran, "We found 1401 putative membrane transporters in the gut and excretory system of this beetle. Narrowing down our search to transporters that are specific for the horseradish flea beetle helped us to identify a group of glucosinolate-specific transporters."

These glucosinolate transporters are located in the excretory system, the so-called Malpighian tubules. The function of the Malpighian tubules in insects is similar to the function of the kidneys in vertebrates. The scientists determined the function of the identified transporters by using RNA interference, an approach in which the expression of a gene of interest is reduced in order to determine its function in the organism: "We silenced the expression of several transporter genes that are localized in the Malpighian tubules and found that the beetles excreted more glucosinolates than a control group of beetles with normal
We silenced the expression of several transporter genes that are localized in the Malpighian tubules and found that the beetles excreted more glucosinolates than a control group of beetles with normal gene expression. Because of the higher excretion rate, the levels of defense compounds in the beetle body went down. Our study is the first to identify transporters in the Malpighian tubules that enable an insect to accumulate plant defense compounds.

Zhi-Ling Yang, Co-author
Research Group Sequestration and Detoxification in Insects,
Max Planck Institute for Chemical Ecology, Jena, Germany
gene expression. Because of the higher excretion rate, the levels of defense compounds in the beetle body went down. Our study is the first to identify transporters in the Malpighian tubules that enable an insect to accumulate plant defense compounds," Yang summarizes.

With their study, the researchers show that sequestration is a complex process and much more than just the uptake of plant metabolites into the animal’s body. The sequestering insect must adapt its entire physiology to use plant defense compounds for its own defense. These adaptations are driven by challenges in its environment: predators, parasites, and pathogens. "Sequestration is probably one of the most complex adaptations that herbivorous insects have evolved. It most certainly also contributes to the evolutionary success of insects that specialize in certain host plants, such as the horseradish flea beetle," says Beran.
The team's findings were published, open access, yesterday, in the journal Nature Communications:

Abstract


Many herbivorous insects selectively accumulate plant toxins for defense against predators; however, little is known about the transport processes that enable insects to absorb and store defense compounds in the body. Here, we investigate how a specialist herbivore, the horseradish flea beetle, accumulates glucosinolate defense compounds from Brassicaceae in the hemolymph. Using phylogenetic analyses of coleopteran major facilitator superfamily transporters, we identify a clade of glucosinolate-specific transporters (PaGTRs) belonging to the sugar porter family. PaGTRs are predominantly expressed in the excretory system, the Malpighian tubules. Silencing of PaGTRs leads to elevated glucosinolate excretion, significantly reducing the levels of sequestered glucosinolates in beetles. This suggests that PaGTRs reabsorb glucosinolates from the Malpighian tubule lumen to prevent their loss by excretion. Ramsay assays corroborated the selective retention of glucosinolates by Malpighian tubules of P. armoraciae in situ. Thus, the selective accumulation of plant defense compounds in herbivorous insects can depend on the ability to prevent excretion.

There is a subtle additional example of designer stupidity there too: in order to accumulate these toxins and sequester them for their own defences, these beetles have needed to inhibit the normal excretory system that their ancestors evolved to get rid of them in the first place. Yet Creationists insist their putative designer is also omniscience, so should have known its work in creating a defense to the toxins it had created to protect the plants was going to have to be undone later.

And then there is the small matter of it having designed the predatory ladybird to eat the horseradish flea beetles, before it designed the flea beetle's defences against being eaten. Any human designer with that lack of foresight would deserve to be sacked as he/she probably wouldn't be trusted to make the tea or sweep the floor properly.

And of course, Creationists are prevented by their religious dogma from offering up multiple designers all working in isolation and in competetion with one another as an explanation for all this, because their dogma wil only permit one designer who has to take all the credit (and in this case all the blame for incompetence and lack of planning). That defense, even if it were open to Creationists, would meean literally millions of desiners all working away in isolation - one for each species.

The more you think about it and the more detail we learn about nature and how species interact and evolve, the more absurd the notion of an intelligent designer being responsible for it all becomes.

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