Monday 14 October 2024

Refuting Creationism - How A Beetle Evolved To Eat Toxic Plants


Red milkweed beetle, Tetraopes tetrophthalmus
Red milkweed beetle genome sequence offers plant-insect co-evolutionary insights

We are continually being assurd by gullible cretionists that the Theory of Evolution (TOE) is 'a theory in crisis' becase a growing body of biologisdts have abandonned it in favour of the creationists superstition of intelligent [sic] design.

This has been a creationist fantasy for at least the last 50 years since when it is supposedly about to happen, any day now, real soon (a bit like The Second Coming of Christ - something which, despite regular announcements that it will happen next Wednesday at noon, never happens - but its gunna, you see!)

However, when we read the scientific publications of these biologists who are allegedly abandoning the TOE, we see no signs whatever of any abandonment; quite the opposite. We see the TOE as firmly embedded in biological science as the Laws of Thermodynamics and the Theory of Gravity are embedded in physics, Atomic Theory is embedded in chemistry and Germ Theory is embedded in epidemiology. It forms the bedrock of the science, without which very little makes any sense.

For example, when a bunch of entomologists wanted to understand how a species of herbivorous beetle can eat a toxic plant, they compared it genomically with a related species that doesn't eat the toxic plant to see how the ability to proccess the toxins evolved.

Of course, being scientists, they reject the idea that the beetle was magically created that way by an unproven supernatural entity because none of that can be falsified and the existence of such an entity can't be established, so there is no logical reason to include one in any answer. The fact that their mummies and daddies might have believed in it is irrelevent to their science, because belief doesn't create facts.

Tell me all about the Red milkweed beetle, Tetraopes tetrophthalmus, please. The Red milkweed beetle (Tetraopes tetrophthalmus) is a species of beetle in the family Cerambycidae, commonly known as longhorn beetles. It's notable for its relationship with milkweed plants, particularly the common milkweed (Asclepias syriaca). Here's an overview of its biology, behavior, and ecological role:

Description
  • Appearance: The Red milkweed beetle is easily recognized by its bright red or orange body with black spots, typically found on its elytra (hardened forewings). Its name, tetrophthalmus, means "four eyes," which refers to the beetle's unusual eye arrangement. Each compound eye is bisected by the base of the antenna, giving the appearance of having four eyes.
  • Size: Adult beetles typically range from 7 to 15 mm in length.
  • Antennae: Long and segmented, typical of longhorn beetles, aiding in sensing the environment.

Life Cycle and Behavior
  • Egg-laying: Females lay their eggs at the base of milkweed plants, often in the soil near the roots.
  • Larval Stage: The larvae burrow into the roots of milkweed plants, feeding on them. This underground feeding stage is crucial for their development.
  • Pupation: The larvae pupate in the soil before emerging as adults.
  • Adult Stage: Adults feed on the leaves, stems, and flowers of milkweed. They are often found in clusters on the plants, making them easy to spot in meadows or fields where milkweed is abundant.

Relationship with Milkweed
The Red milkweed beetle is one of several insects that specialize in feeding on milkweed. Milkweed contains toxic compounds called cardenolides (or cardiac glycosides), which are harmful to many animals. However, Tetraopes tetrophthalmus, like monarch butterflies, has evolved mechanisms to tolerate these toxins. In fact, by consuming milkweed, the beetles become toxic to potential predators, making them less likely to be eaten.

Defense Mechanisms
The beetle's bright red and black coloration is an example of aposematism, where conspicuous colors warn predators of toxicity. This visual warning, coupled with the cardenolides they ingest from milkweed, makes them unpalatable to many birds and other potential predators.

Habitat and Distribution
  • Habitat: The Red milkweed beetle is commonly found in fields, meadows, and prairies where milkweed grows. It is particularly associated with common milkweed but may also be found on other milkweed species.
  • Distribution: It is native to North America, primarily found in the eastern and central United States and parts of Canada.

Ecological Role
As a milkweed specialist, the Red milkweed beetle plays a role in the milkweed ecosystem by feeding on the plants and helping to regulate plant growth. It is also a part of the food web, serving as prey for certain specialized predators that can tolerate its toxins. Additionally, the beetles contribute to the pollination of milkweed flowers, although they are not the primary pollinators.

Interesting Facts
  • Mimicry: Like other milkweed feeders, such as monarch butterflies, the Red milkweed beetle benefits from mimicry. Its bright coloration sends a clear warning signal, which other species may imitate in a phenomenon known as Müllerian mimicry.
  • Communication: The beetles communicate with each other through sound and vibrations. Males and females use these signals during mating rituals.

The Red milkweed beetle is a fascinating example of insect-plant coevolution, with its life intricately tied to the toxic milkweed plant.
They didn't set out to prove the TOE or to refute creationism - no serious research biologist bothers with those now-a-days because they are established without any real doubts, so their refutation of creationism was again quite incidental yet comprehensive, simply by reveling the truth.

The bunch of entomologists in question were from the University of Arkansas Agricultural Experiment Station, the University of Memphis and the University of Wisconsin Oshkosh. They have just sequenced and assembled the entire genome of the host-specialist milkweed beetle (Tetraopes tetrophthalmus) and compared aspects of genome biology to a relative, the host-generalist Asian longhorned beetle (Anoplophora glabripennis, an invasive species in the USA which feeds on a variety of trees.

The team have recently published their findings in the Oxford University Press Journal of Heredity, published on behalf of the American Genetic Association. Their work is described in a a University of Arkansas Divion of Agriculture news release:
Red milkweed beetle genome offers insight into plant-insect interactions
Fast facts
  • Genome of host-specialist red milkweed beetle compared to generalist relative
  • Fewer genes related to taste, smell offer clues to genome evolution
  • Plant cell-wall degrading enzymes targeted to learn more about plant digestion

Studying the secrets of how the common red milkweed beetle can safely feed on a toxic plant helps illuminate the ecological, evolutionary and economic impact of insect-plant interactions from a genomic perspective.

Although the relationship between the red milkweed beetle and milkweed plants has been studied for nearly 150 years, an Arkansas Agricultural Experiment Station scientist joined colleagues at the University of Memphis and the University of Wisconsin Oshkosh to do what no one else has done — curate the beetle’s genome and its arsenal of genes related to plant-feeding and other biological traits.

With support from the National Science Foundation, they sequenced and assembled the entire genome of the host-specialist milkweed beetle (Tetraopes tetrophthalmus). They then compared aspects of genome biology to a relative, the host-generalist Asian longhorned beetle (Anoplophora glabripennis), which is an invasive exotic species that feeds on a variety of trees important to forestry.

Their study, “Functional and evolutionary insights into chemosensation and specialized herbivory from the genome of the red milkweed beetle,” was published in the Journal of Heredity by the American Genetic Association this summer.

From a biological standpoint, there is a lot of correspondence that suggests that longstanding interactions between milkweed beetles and their toxic milkweed hosts should influence the biology of both interacting partners. But, to date, no one had assembled a milkweed beetle genome, which opens the door for targeting a lot of interesting questions at the interface between insect and plant.

Assistant Professor Richard Adams, co-lead author.
Department of Entomology and Plant Pathology
University of Arkansas, Fayetteville, AR, USA.


Adams is an assistant professor of agricultural statistics in the department of entomology and plant pathology for the University of Arkansas System Division of Agriculture. He is also a member of the Center for Agricultural Data Analytics, a new initiative of the experiment station, and he teaches statistics courses in the Dale Bumpers College of Agricultural, Food and Life Sciences.

Scientific development
Milkweeds and milkweed beetles (genus Tetraopes) have been studied as valuable models for over a century of research into ecology, evolution, developmental biology, biochemistry of toxins and more, Adams said. They are also providing an interesting and compelling case of co-divergence patterns between insect and plant — meaning the plants and insects share similarities in the timing of co-evolution across their histories of interaction, Adams explained.

The research team showed that the red milkweed beetle has an apparent expansion of genes from the ABC transport family, which may help them feed on milkweeds and sequester its toxins inside beetle tissues. Milkweeds are renowned for their toxic latex cocktails, which affect the balance of sodium, calcium and potassium that keeps heart cells pumping. Adams said this genome provides insights into the genes the beetle has evolved to safely interact with its toxic milkweed hosts.

Milkweeds produce a particularly nasty type of toxin called cardiac glycosides alongside other types of toxins that come with it. For many insects that eat it, the toxin will block their sodium-potassium pumps. But this beetle developed a way to not only resist the toxin, but also sequester it, hold on to it, to keep the beetles themselves safe from would-be predators.

Assistant Professor Richard Adams.

The study also pinpointed differences in genes responsible for smell, taste and metabolic enzymes that degrade the plant cell well. Adams said it provides a new vantage point for exploring the ecology and evolution of specialized plant-feeding in longhorned beetles, and other plant-eating beetles.

Applications in agriculture, human health
These findings may help us understand and identify the genetic factors that shape agricultural and forestry pests and allow them to successfully feed on plants, as well as evade control efforts. Most animals that can digest woody plant material depend on microbes in their gut to break down plant cell walls; however, many plant-eating beetles do not.

Adams said many plant-feeding beetles, including longhorn beetles, acquired the ability to break down plant cell walls through horizontal gene transfers from microbes. By looking at the diversity of proteins encoded within beetle genomes, he said scientists can learn about the genomic basis of beetle biology, evolution and diversity, as well as their propensity for interactions with plants.

Nature has made an incredible diversity of genes and genomes already out there that we have not yet deciphered. Understanding this diversity holds great promise for informing agriculture, forestry and human health. Herbivorous beetles would have a difficult time feeding on plants without their metabolic enzymes, because they can’t eat effectively without them.

Learning more about chemosensory biology — how an organism senses its environment, like sensing a host plant or reproductive partner — has broad relevance for understanding insect-plant interactions, which is intensively relevant to agriculture and forestry.

Assistant Professor Richard Adams.

In addition to studying the genomic DNA of the milkweed beetle, the team collected RNA from male and female red milkweed beetle antennae to learn more about how they seek out mates and food through chemosensation.

The RNA profile provided the first transcriptomic resource for Tetraopes. A transcriptome contains a range of genes that are transcribed into RNA molecules an organism expresses in a tissue or set of cells.

The DNA provides a gene sequence, the RNA offers “a better resolution of the gene and its expression, including how often the gene is getting made,” Adams explained.

Co-authors of the study included Terrence Sylvester and Rongrong Shen, postdoctoral researchers at the University of Memphis with Duane D. McKenna, William Hill Professor in the department of biological sciences and director of the Center for Biodiversity; Matthew A. Price, formerly with the University of Wisconsin Oshkosh and now with the University of Hawaii at Manoa; and Robert F. Mitchell, formerly at the University of Wisconsin Oshkosh and now associate professor in the department of entomology at Pennsylvania State University.
Abstract
Tetraopes are aposematic longhorn beetles (Cerambycidae) that feed primarily on toxic plants in the genus Asclepias (milkweeds). Studies of Tetraopes and their host plants have revealed compelling evidence for insect–plant coevolution and cospeciation. We sequenced, assembled, and annotated the genome of the common red milkweed beetle, Tetraopes tetrophthalmus, and explored gene content and evolution, focusing on annotated genes putatively involved in chemosensation, allelochemical detoxification, and phytophagy. Comparisons were made to the Asian longhorned beetle (Anoplophora glabripennis) genome. The genome assembly comprised 779 Mb distributed across 1,057 contigs, with an N50 of 2.21 Mb and 13,089 putative genes, including 97.3% of expected single-copy orthologs. Manual curation identified 122 putative odorant receptors (OR) and 162 gustatory receptors (GR), the former number similar to A. glabripennis but the latter only 69% of the A. glabripennis suite. We also documented a greater percentage of pseudogenic GRs and ORs compared to A. glabripennis, suggesting an ongoing reduction in chemosensory function, perhaps related to host specialization. We found lower diversity within certain well-studied gene families predicted to encode putative plant cell wall degrading enzymes in the T. tetrophthalmus genome, perhaps also due to host specialization. Exploring genes relevant to stress and allelochemical detoxification revealed evidence of an abundance of ABC-family genes in the T. tetrophthalmus genome, which may be related to sequestering toxic cardiac glycosides. Our studies further illuminate the genomic basis and evolution of chemosensation in longhorn beetles and provide a new vantage point from which to explore the ecology and evolution of specialized plant-feeding in Tetraopes and other phytophagous beetles.

Richard Adams, Terrence Sylvester, Robert F Mitchell, Mathew A Price, Rongrong Shen, Duane D McKenna
Functional and evolutionary insights into chemosensation and specialized herbivory from the genome of the red milkweed beetle, Tetraopes tetrophthalmus (Cerambycidae: Lamiinae),
Journal of Heredity, 2024;, esae049, https://doi.org/10.1093/jhered/esae049

© 2024 Oxford University Press/ American Genetic Association.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.
Yet another comprehensive rebuttal of creationist dogma, with no sign whatever that the TOE is not fit for purpose. There is a very clear working assumption on the part of the scientists that comparing the genomes of two related species of beetle, one which eats toxic plants and one which doesn't, will show which genes have evolved to cope with a toxic diet. And the mechanism turned out to be exactly what the TOE predicts - evolution by change in allele frequency over time, and the mechanism of evolution turns out to be somethign else creationists insist can't hapen - new genetic information arising by 'expansion' of existing genes. In other words by gene duplication and repurposing.

And of course we also see the evidence of an inevitable co-evolutionary arms race in which the plant evolves more toxic chemicals while the beetle evolves more ways of coping with them - somethign that belies the notion of any intelligence involved in the process, simply because competing with oneself in an arms race is not the act of an intelligent designer. However, it is the predictable result of a blind, utilitarian evolutionary process working without a plan with one species being the environmental selector for the other.
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