Evolution News - How Ants Evolved by Losing Complexity

Cataglyphis bombycina workers and (larger) queens.

Credit: Philip Hönle

Losing flight had huge benefits for ants, finds new study | Okinawa Institute of Science and Technology Graduate University OIST

How did ants evolve their famous strength and endurance, which far exceeds even the fittest and strongest mammals in comparison to their size?

The answer to this was provided yesterday by a combined team of researchers from Institut d’Écologie et des Sciences de l’Environnement, Sorbonne Université, Paris, France and the Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.

And Once again, a science paper refutes another sacred Creationist dogma - that so-called 'macro-evolution' always involves an increase in complexity and is therefore impossible because the new information needed can't arise naturally, so needs a magic man to provide it.

This obviously ignore that marked loss of complexity we see in parasites - which Creationist frauds are understandably reluctant to talk about to their would-be dupes.

But this example has nothing to do with parasites and is about one of the most successful branches of the phylum Insecta - ants. Ants are members of a class of insects known as the hymenopterans, which includes wasps and bees. The name means 'membrane-winged', but in the case of the worker ants and mature queens, the wings are absent, having been shed soon after mating in the case of the queens, or failing to develop at all in the case of the sterile worker casts.

A detailed analysis by the research team has shown how it was highly beneficial to ants to lose their wings during their evolution. Their results are published open access in the journal Frontiers in Zoology:

Abstract

Background

Explanations for the ecological dominance of ants generally focus on the benefits of division of labour and cooperation during foraging. However, the principal innovation of ants relative to their wasp ancestors was the evolution of a new phenotype: a wingless worker caste optimized for ground labour. Ant workers are famous for their ability to lift and carry heavy loads, but we know surprisingly little about the morphological basis of their strength. Here we examine the consequences of the universal loss of flight in ant workers on skeletomuscular adaptations in the thorax for enhanced foraging on six legs.

Results

Using X-ray microcomputed tomography and 3D segmentation, we compared winged queens and wingless workers in Euponera sikorae (subfamily Ponerinae) and Cataglyphis savignyi (subfamily Formicinae). Workers are characterized by five major changes to their thorax: i) fusion of the articulated flight thorax (queens) into a rigid box optimized to support the muscles that operate the head, legs and abdomen, ii) redesign of internal cuticular structures for better bracing and muscle attachment, iii) substantial enlargement of the neck muscles for suspending and moving the head, iv) lengthening of the external trochanter muscles, predominant for the leg actions that lift the body off the ground, v) modified angle of the petiole muscles that are key for flexion of the abdomen. We measured volumes and pennation angles for a few key muscles to assess their increased efficacy. Our comparisons of additional workers across five genera in subfamilies Dorylinae and Myrmicinae show these modifications in the wingless thorax to be consistent. In contrast, a mutillid wasp showed a different pattern of muscle adaptations resulting from the lack of wing muscles.

Conclusions

Rather than simply a subtraction of costly flight muscles, we propose the ant worker thorax evolved into a power core underlying stronger mandibles, legs, and sting. This contrasts with solitary flightless insects where the lack of central place foraging generated distinct selective pressures for rearranging the thorax. Stronger emphasis is needed on morphological innovations of social insects to further our understanding of the evolution of social behaviours.

Christian Peeters, Roberto A. Keller, Adam Khalife, Georg Fischer, Julian Katzke, Alexander Blanke & Evan P. Economo
The loss of flight in ant workers enabled an evolutionary redesign of the thorax for ground labour
Frontiers in Zoology 17, 33 (2020) DOI:10.1186/s12983-020-00375-9

Copyright: © 2020 The authors. Published by Springer Nature
Open access
Reprinted under a Creative Commons Attribution 4.0 International License (CC BY 4.0)

So, a worker ant owes its ability to do its job - to forage and find food and supplies to carry back to the colony, to the fact that during the evolution of ants, they lost their wings. This mave available the necessary room in a rigid thorax for the large, powerful muscles needed to power the legs and the neck muscles to support the head and to carry the loads it picked up, so giving ants their famous lifting and carrying power and ability to run huge distances in comparrison to their body-weight.

This contrasted to the arangement in the flightless wasps, which are solitary and eat what they find, having no need to carry it back to a nest.

As I frequently seem to be pointing out in this blog, onc again, without effort of intent, simply by discovering the facts, biologists have once again refuted another of Creationism's essential doctrines.

And once again, Creationists will need to ignore the evidence.

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