Tuesday, 3 August 2021

Evolution News - Inadvertently Refuting Creationism Again

Right: hyper-parasitoid wasp Mesochorus stigmaticus parasitising the larvae of a parasitoid wasp Hyposoter horticola within the caterpillar of Glanville fritillary butterfly. Left: adult Glanville fritillary.
Image: Saskya van Nouhuys
Like matryoshka dolls: one insect species introduced decades ago to a small island had an effect on several insect populations  | University of Helsinki

An open access paper published today in the journal, Molecular Ecology, refutes so many favourite Creationist dogmas that it's hard to know where to begin.

The paper is by scientists from Helsinki University, Finland, and Cornell University, USA, and is an account of the consequences of the introduction of a species of butterfly to a small Finish island of Sottunga (full name Storsottunga) in the Åland Islands, at the mouth of the Gulf of Bothnia, at the North-Eastern end of the Baltic Sea.

What was also inadvertently introduced with the larvae of the Glanville fritillary that were taken to the island, were a couple of parasitic insects and a symbiotic bacteria, so what was created was an experiment on the founder effect and how a species and its symbionts/parasites evolve over time, and how this environmental change affects the evolution of other species in an ecosystem.

From the University of Helsinki News release:
What the researchers did not know 30 years ago was that the larvae carried along with them the butterfly parasitoid wasp Hyposoter horticola. The parasitoid then carried its hyperparasitoid wasp Mesochorus stigmaticus, and a mum-to-offspring transmitted bacterial symbiont Wolbachia pipientis that somehow increases the susceptibility of the host H. horticola to M. stigmaticus.

If local butterfly populations are small and unstable their parasitoids must be mobile enough to find hosts elsewhere. We have been able to show that the parasitoid H. horticola is dispersive in Åland. Furthermore, it has persisted and shows less genetic structure than the butterfly host. This probably explains their genetic mixing with populations on nearby island after introduction to Sottunga. Introduced genotypes have potentially kept nearby populations from extinction during host population declines,

Dr. Anne Duplouy, Lead author
Organismal and Evolutionary Biology Research Program,
The University of Helsinki, Helsinki, Finland
Larvae of the Glanville fritillary butterfly, Melitaea cinxia, were introduced to the island of Sottunga in the Åland Islands, Finland, in 1991. The original research project for which this introduction was aimed failed. However, although the island was previously free of the butterfly, the relocated species persisted, offering the ground for investigating how an entire insect community could be affected by one introduction event.

Thanks to yearly survey of the Åland butterfly population, researchers from the University of Helsinki and the Cornell University, USA, have shown that the butterfly population introduced to Sottunga has faced several bottle necks since 1991. It consequently is genetically quite diminished and faces a high risk of extinction.

The hyperparasitoid M. stigmaticus isn’t quite as mobile and has a smaller population size, so it suffers from inbreeding and is absent from some islands. Where the hyperparasitoid is absent, the parasitoid lineages with Wolbachia can flourish.
Over the 30 years the 'experiment' has been running, the population of Glanville fritillaries on Sottunga Island has diverged markedly from the parent population, due to the founder effect and subsequent population crashes resulting in genetic bottlenecks and reduced genetic variability.

The genetic signature of introduced wasp lineages gives us a window into what has happened in an island archipelago over the 25 years since their accidental introduction, including persistence through population bottlenecks, dispersal and interbreeding, as well as sorting among lineages depending on a hyperparasitoid and bacterial symbiont.

Dr. Saskya van Nouhuys, Co-author
Cornell University, USA,
On the other hand, one of the parasitoid wasps, H. horticola, which is dependent on its host for breeding success, so should crash when its host population crashes, is mobile enough to interbreed with those on neighbouring islands, and so 'import' fresh genes. Consequently its genetic variability is much less narrow than the butterfly's. The first thing for Creationists to note, is how their supposedly all-loving intelligent [sic] creator has not just one but two malevolent parasites in this mix. Not content with creating a parasitoid wasp to kill Glanville fritilleries, it has created a parasitoid wasp to kill the parasites it created to kill the butterflies! It takes a special form of sadism to go to those lengths to kill its creation in especially nasty ways. It created a butterfly, then created a parasitic wasp to kill it with, then, amazingly, created another parasitic wasp to kill that parasite with! But it gets worse!

We have integrated population genetic and population ecology methods to find exciting insights about host and parasitoid ecology, as well as the influence of their bacterial symbionts over such short period of time.

Dr. Abhilash Nair, co-author
Organismal and Evolutionary Biology Research Program
The University of Helsinki, Helsinki, Finland
It then created a bacterium to help protect the first parasite from the second! And the symbiotic bacteria, W. pipientis takes some beating as an example of one organism giving another some additional advantage as a parasite in its own right - an arrangement which gives the Wolbachia an advantage, riding on the back of a parasite. The exact mechanism by which it does it is not fully understood, but strains infected with it are much better at avoiding being parasitised themselves, than those without it.

This is not the first time the malevolent designer has pulled off a sneaky trick with Wolbachia, either. In a 2015 paper, Japanese scientists showed how the same species of Wolbachia does just the opposite; it improves the ability of another parasitic wasp, Asobara japonica, to find its victims. When 'cured' of Wolbachia with tetracyclin, the formerly infected wasps do no better than the Wolbachia-free strain.

Wolbachia seems to be a particular favourite of Creationism's beloved mendacity. It is a common endosymbiont of many arthropod species; in some it is a parasite and, for example, differentially kills male larvae or prevents the male larvae developing in the eggs. In some species, it even takes control and turns its host into an automaton. In the case of the Sottunga Island 'experiment', the relative rarity of the hyperparasitoid means the strain infected with Wolbachia can flourish and the bacterium can become fixated in the population, i.e. present throughout the local population.

Creationists seem to find this evidence of hopelessly muddled objectives and forgotten purpose as evidence of the design abilities of their favourite deity! It's hard to think of a worse example of the outcome from bad design! It is only understandable as the product of intelligent direction if the intelligence is also sadistic and enjoys watching its creation suffer by, in this case, being eaten alive by parasitoid wasp larvae.

In fact, of course, it's a wonderful example of a process without a plan, and exactly what any decent evolutionary biologist would expect.

Also to be noted is the way the scientists interpret the entire thing, not in mystical, magical terms, but as examples of perfectly natural genetic evolution in action, fully in accord with modern neo-Darwinian gene-based evolutionary theory. No sign of the TOE being somehow a 'theory in crisis', like Creationist frauds tell their credulous dupes, of course. Another example of the lies they fool their marks with, like snake-oil sellers.

In their open access paper, the scientists say:
Abstract Population bottlenecks associated with founder events strongly impact the establishment and genetic makeup of populations. In addition to their genotype, founding individuals also bring along parasites, as well as symbionts that can manipulate the phenotype of their host, affecting the host population establishment, dynamics and evolution. Thus, to understand introduction, invasion, and spread, we should identify the roles played by accompanying symbionts. In 1991, the parasitoid wasp, Hyposoter horticola, and its associated hyperparasitoid were accidentally introduced from the main Åland islands, Finland, to an isolated island in the archipelago, along with their host, the Glanville fritillary butterfly. Though the receiving island was unoccupied, the butterfly was present on some of the small islands in the vicinity. The three introduced species have persisted locally ever since. A strain of the endosymbiotic bacterium Wolbachia has an intermediate prevalence in the parasitoid H. horticola across the main Åland population. The infection increases its susceptibility of to hyperparasitism. We investigated the establishment and spread of the parasitoid, along with patterns of prevalence of its symbiont using 323 specimens collected between 1992 and 2013, from five localities across Åland, including the source and introduced populations. Using 14 microsatellites and one mitochondrial marker, we suggest that the relatively diverse founding population and occasional migration between islands might have facilitated the persistence of all isolated populations, despite multiple local population crashes. We also show that where the hyperparasitoid is absent, and thus selection against infected wasp genotypes is relaxed, there is near-fixation of Wolbachia.

Duplouy, Anne; Nair, Abhilash; Nyman, Toshka; van Nouhuys, Saskya
Long-term spatiotemporal genetic structure of an accidental parasitoid introduction, and local changes in prevalence of its associated Wolbachia symbiont
Molecular Ecology 00, 1– 13. DOI: 10.1111/mec.16065

Copyright: © 2021 The authors. Published by John Wiley & Sons, Inc
Open access
Reprinted under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International license (CC BY-NC-ND 4.0)
So many refutations of so many sacred Creationist dogmas!

And so it goes on with just about every scientific paper, especially ones dealing with biology/ecology and geology/archaeology. Of course, very few scientists these days set out to confirm evolutionary theory or refute Bronze Age Creationist superstion; it's just that all the facts testify for the former and against the latter, so simply revealing the facts is enough.

The amazing thing is that Creationism continues, albeit in reducing numbers particularly in younger people, in America and elsewhere, where primitive superstitions fill the gap between ignorance and education.

But then the USA is a country in which a significant minority voted for Donald Trump and even think he made a good job of his disastrous go at playing Leader of the Free World, with a Twitter Account.

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