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Evolution of Insects

Taking flight
How does 'my theory' fit with the evolution of insects?  I knew that the dominant soil animals are more 'primitive' than insects - evolutionarily speaking - but how does insect evolution fit with the evolution of soil? It is said that the evolution from primitive wingless insects to winged insects is pretty well known. (Tree of Life). However, here I talk about the evolution of primitive non-insects into flying forms - many insects.

The great explosion of insect types was in the Carboniferous period - the period immediately following when I say soil creation occurred (late Devonian) Insects are classified according to their wings - in other words, their key character is that of flight. They took to the air.  All types of insects are classed according their wings, or 'ptera'. Lepidoptera - moth and butterflies, are classed by their s'scaly' wings - Lepidoptera. Flies are 'diptera - because they only have two wings rather than the more normal four. Beetles are Coleoptera - 'hard' wings that cover flying wings. 

I thought insects may have first come out of the water - e.g. dragonflies are very ancient. But do they come out of the soil? While we see a dragonfly nymph emerge form the water turn into an adult and fly away, we could be forgiven for thinking that thisis how evolution happened. But wait. To fly like that in the air, it needs breathing mechanisms to work in air and body capable of withstanding drought. they could not get that overnight. They could not have just 'landed' but needed to evolve these drought resistant mechanissms and that would takle millions of years. So where did this occur?.

I believe, insects like dragonflies and mayflies, diving beetles, went back to the water. Dragonflies evolved around 325-330mya - well after my soil theory. While I had thought that perhaps insects emerged and evolved from water on to 'the land',  it seems it is the other way round - that they evolved from soil, from soil creatures, to the air and some went back ot water as adults

working on this..it sounds like they are just there, yet they must have come from somewhere..(soil?)
Wiki "Fossil remains of air-breathing insects,[18] myriapods and arachnids[19] are known from the late Carboniferous, but so far not from the early Carboniferous.[6] The first true priapulids appeared during this period. Their diversity when they do appear, however, shows that these arthropods were both well developed and numerous. ..but where did that come from?

They were large - attributed to the moistness of the environment (mostly swampy fern forests) and the fact that the oxygen concentration in the Earth's atmosphere in the Carboniferous was much higher than today.[20] This required less effort for respiration and allowed arthropods to grow larger with the up to 2.6-meter-long (8.5 ft) millipede-like Arthropleura being the largest-known land invertebrate of all time. 
Among the insect groups are the huge predatory Protodonata (griffinflies), among which was Meganeura, a giant dragonfly-like insect and with a wingspan of ca. 75 cm (30 in)—the largest flying insect ever to roam the planet. Further groups are the Syntonopterodea (relatives of present-day mayflies), the abundant and often large sap-sucking Palaeodictyopteroidea (one I'm looking at particularly) the diverse herbivorous Protorthoptera and numerous basal Dictyoptera (both ancestors of cockroaches).[18]"

Recent major research carried out by 100 collaborators from 10 countries "clarifies insect evolutionary history. It shows that insects started flying 400 million years ago, long before any other animal, and at nearly the same time land plants first grew substantially upwards to form forests." Whenever you see in evolutionary theory about the 'first specimen', you have to take into account that this is NOT the main explosion of numbers, which usually occurs some time later. So it fits quite well.

Most insects are classified according to their wings - or 'ptera' in ancient Greek. Hence flies are diptera  (2-winged), butterflies are lepidoptera (scaled wings), and beetles are coleoptera (hard winged).

Most soil animals are primitive - evolutionarily speaking.  None have a full metamorphosis like the more advanced insects. The more primitive insects have a similar metamorphosis as soil arthropods - ie 'hemimetabolous'.. they just go through a series of nymphal stages, rather than have eggs which turn into larvae thence to pupae and finally, adult forms - called 'holometabolous'. 


Have just discovered M S Ghilarov 'Regularities in adaptations of arthropods to the terrestrial life 1949. Reprint 1970.' NAUKA. - publishing house of Academy of Sciences ion the USSR.

He spent 35 years researching and explaining how he believed that insects had evolved through the soil. To develop their organs, and metabolism, like their respiratory system, excretion, water retention, reproduction, egg protection & nitrogen metabolism they need the stable soil conditions to evolve slowly from aqueous to terrestrial life. It did not just happen.  Vannier says to do this requires the 'Poroshere'. More to come as I translate. Curious nobody seems to mention this is 'insect evolution' reviews.
Here he is his Introduction to 'Regularities' Reprint 1970
Insects are the most completely adapted to life on land. In the insect complex, there are at least two independent phylogenetic branches of the transition from the hidden (soil, in the wide sense of the word) way of life to living in open air - in collembolans and in ectogatous insects. At the same time, in different groups of insects, there is an unequal degree of connection with the original wet habitats.

Rows of emerging transitions of release from constant communication with a wet environment can be traced in different classes of centipedes. Among helixes, such series are outlined in general in a complex of different orders of arachnids and even within smaller taxa (for example, in ticks). Akhelitserovye (??) in general, allow us to analyze the whole range of transition from life in the water to the terrestrial existence.

If the currently distinguishing selection of scorpions from the arachnid class to the merostom class, then scorpions give another parallel branch of evolution from aquatic forms (fossil Palaeophonus) to terrestrial.

Finally, phylogenetically young and ecologically very complete series of transitions illustrate crustaceans such as isopods. The secondary transitions to life in the water of insect larvae (and the secondary transitions of secondary-water larvae to life on land!) Make it possible to isolate more plastic adaptation features when changing habitats.

At present, it is difficult to imagine that just 30 years ago, the naively fantastic representations of A. Handlirsh, who painted the path of evolution from trilobites directly to winged insects, such as Palaeodictyoptera, were widespread.

Refinement of the phylogenetic pathways of evolution of terrestrial arthropods, the allocation within the type of different levels of adaptation to life outside water (in the soil and other wet substrates and in the open atmosphere)."

See file below of my translation of his Introduction in 
'Regularities in adaptations of arthropods to the terrestrial life 1949. Reprint 1970.' NAUKA.  Original Ghilarov in black, my addition in brown.


More primitive insects are called 'hemi-metabolic - going through various growing stages, each a bit more developed There may be several or quite numerous stages of 'nymphs'. All soil animals - both springtails and mites, just go through a series of nymphal stages before maturing. More advanced insects have a complete metabolic development. This where the series of growth stages are quite distinct. The most obvious are butterflies bursting from a pupa that followed the caterpillar stage hatching from eggs. But this form of development is a good 100 million years later, So we can expect the more primitive insects, like earwigs,  to have a series of nymphs - like the soil animals.
Earwig metamorphosis

According to Tim Cockerill, talking with Brain Cox, metamorphosis is probably one of the reasons insects have become so successful. The four most diverse groups  of animals on the planet - wasps, beetles, flies and moths, all do it.  the most important things for species to survive is to eat and to reproduce. These creatures have one half of their life cycle designed - by natural selection, to take on as much food as possible. The larvae is an eating machine. The adult is there to disperse, mate and lay eggs. If my theory is right about insects evolving from soil animals, then they come back to the soil for their larvae stage in many of them - eg leatherjackets for craneflies, and chafer grubs for cockchafer beetles. 

Did apterygotes gave rise to insects?

It seems that colonisation and creation of the soil took place by creatures that dominated the soil, that then evolved into insects - characterised by taking to the air.  We need to look at apterygotic arthropods (ones with out wings) and try and work how these may have evolved wings. According to 'The Terrestrial Invasion, the apterygotes- Diplura, Protura and Collembola (that until relatively recently were considered insects), along with Symphyla, all developed similar adaptations in movement from marine to 'land'. We have seen them all play vital roles in the soil. Is it likely that these creatures were the ancestors of insects? Without them colonising and creating soil, where would insects have come from?

Probably the best book on insect evolution - Grimaldi & Engels, says "Early terrestrial tracks document the presence of various arthropod lineages and support the view that insects themselves originated in a terrestrial environment. It is interesting to note that the arthropods comprised the earliest know terrestrial animals." Grimaldi & Engels Chapter 3 p.110 They confirm that the creatures that are the progenitors of insects are springtails, protura and symphylans - but they see them as part of 'Invasion of the land' rather than the formation of the soil. See what I think of that 'Invasion of the land ideas'. .According to Chapter 3, 'Arthropods and Insect evolution', track their evolution up to the time of insect evolution proper, they have sub head 'Invasion of the land'. They identify the apterygota but give no explanation of their role, either in the soil or in how they may have changed to evolve into insects.

Apterygotes include springtails (Collembola) form the largest of the three lineages of modern hexapods (six legged creatures) that are no longer considered insects . The other two are the Protura and Diplura. Although the three orders are sometimes grouped together in a class called Entognatha because they have internal mouthparts, they do not appear to be any more closely related to one another than they all are to insects, which have external mouthparts (Ectognatha)

Springtails - often found in pools and ponds would have sprung onto the land and there developed their relation with plants, which we have seen elsewhere on Birth of the Earh. They found new role, eating root debris, and fungal debris. keeping the plants health and their role with fungi bringing in nutrients - in the first place from volcanic ash dust. As time went on, they have moved further down the deepening soil, loosing their 'springtail' (furca) as no using springing when surrounded by soil. Their distinct character - collophore - is 'sticky', and is presumably how fungal spores get stuck on them move around the soil. But why do the collembola have it these organs perhaps picking up spores from the sporohore in order to be fertislised. There is no internal fertiisation, as with insects.  

The three orders - collembola, protura and diplura are sometimes grouped together within a class called Entognatha. Along with insects, which are in the class Insecta, they make up the subphylum Hexapoda, a reference to their six legs. Formerly, Protura, Diplura and Collembola were grouped with the order Thysanura (silverfish) into the class Apterygota, and you may still come across this old classification system. According to Insect Identification Kit "The three orders were removed from class Apterygota and put into their own class once scientists determined that they were not in the evolutionary lineage of insects. In other words, these three orders did not give rise to modern-day insects".

Others seem pretty certain that apterygotes are related to insects. The term apterygote came from Greek words meaning “without wings.” These are primitive, wingless insects and they hexapods which mean they have six legs. Some of them do not have eyes. Scientists believed that fossils found, occurred during the Devonian period that is 417-354 million years ago. that puts them in the right timeframe for making soil. They were classed as insects until 'recently' - Dividing Hexapods beween Entognatha (Collembola and Dipurans) - internal mandibles and Ectognatha - Insects  was suggested over a 100 years ago by Grassai but really defined by Hennig in the around the 1960's and 1970s.


Phylogentic analyses supports monophlyly of Hexapoda and suggests paraphlyly of Endognatha says their findings are expected to provide additional insights into the origin of hexapods and the processes involved in the adaptation of insects to life on land." Again it sounds like they just flopped on to the land, rather than evolved through the soil. They quote:
"A Carboniferous dipluran fossil showed that only Diplura of Entognatha (mainly insects) shares an ancestral ground plan with Ectognatha, suggesting a close relationship between Diplura and Ectognatha . Comparative embryological evidence and phylogenetic analyses based on morphological and some molecular data (EF-1α, EF-2, and RNA polymerase II sequences) also suggest that a relationship exists between Diplura and Ectognatha."  It is not a big step to go from 'Entognatha - where mouthparts are protected - which would be necessary moving through soil, to external mouthparts of  Ectognatha, physically feasible above ground. 

Diplurans are one of three main groups along with springtails and protura that have internal mouthparts. Hexapods - including all insects have external mouthparts. Diplurans are not earwigs, but can't help but think they could have evolved into them, especially as earwigs inhabitat the soil surface..and thus still in soil-like environment but have the potential to fly. Look at the nymphal stages of earwig development above, and see how close the early stages resemble diplurans. More on how Diplurans may be confused with earwigs

Diplurans not EarwigsGlobal Soil Diversity

I think that different versions of insects arose at different times/places, although they may come from 'common stock'. The potential to colonise the air above the soil - to escape an ecosystem with many ecological niches already occupied must have led to a massive evolutionary opportunities It seems  pretty obvious that it was the soil that was first created/colonised, and from there, the creatures went on the the surface - where their mouthparts could become exposed. From there they took to the air - and needed wings to do it. But many people think insects came straight from water and landed. Some insects have larval forms living in the soil. Did these insects with soil larvae (beetles, and flies) evolve out of the ground, or then go back to use the soil as larva? Or were some like the larval/ nymphal forms, that evolved another life stage that could eat  on top of the  land and fly in the air? There will be both. 
Otherwise you cant help but think Diplura (earliest 350mya) had enough time to evolve into earwigs (around 200 mya).

4 Class Scheme
This needs working on...Ephmeroptera = Mayflies,  Odonata = Dragonflies both insects. According to this diagram, the apterygotes became silverfish (Thysanura) which evolved into insects. However it was not until the primitive hexapods had helped create and colonise the soil, was there the development of insects, as they took to colonise the new space above the soil  - the air.


Ancient cockroaches looked very much like this modern oneCockroaches have been around for a very long time -Ancient cockroaches looked very much like this modern one, Macropanesthia rhinoceros.

© Natural History Museum, London. From the Encyclopedia of Life.

The Carboniferous, around 300 million years ago, is sometimes called the Age of Cockroaches because insects broadly resembling modern roaches flourished during that era. That follows the period I'm talking about..From over 330 mya this cockroach like creature. There were 'roachoids' before cockies..
From same time, see this creature Anebros phrixos as a 3D rendering of 300+mya. It is called a 'nymph' but were they nymphs, or creatures that existed previously and evolved another stage in development later - with wings? Like this..


"Beetles and woody material go back a long way, probably to the very beginnings of this group of insects. The first beetles may have sought refuge in woody material that fell into freshwater and from there they evolved to exploit this resource. Much of the extraordinary beetle diversity we see today is rooted in this habitat. Indeed, a large proportion of living beetle families are associated with woody material for most of their life cycle. For more information take a look at this recent paper on the evolution and genomic basis of beetle diversity." From Saproxylic beetles.

Or could it be that beetles - larval forms - came out of the soil to invade fallen trees lying on top?

(not insects, but same plot)
Did they evolve into centipedes - or other way round? Video of 2 sympylans moving
Called 'garden' or 'house' centipedes
house centipedeSymphyla
, symphyla
 are translucent, and only distantly related to true centipedes. 

They have several features linking them to early insects, such as a labium (fused second maxillae), an identical number of head segments and certain features of their legs.

Despite their common name, morphological studies commonly place them as more closely related to Myriapoda than the centipedes, in the clade Progoneata. Check out Phylogenya of Myriapoda. Myriapoda, a subphylum of Arthropoda, comprises four classes, Chilopoda (Centipedes)  Diplopoda (Millipedes)  Pauropoda (here..)

and Symphyla. Molecular studies show conflicting results, with some supporting the Progoneata clade, others centipedes.

A myriapod is the earliest known terrestrial animal - found from around 400 mya.

Tardigrades have probably been around for half a billion years, as they live in bryophytes and have incredible ability to survive, so could have withstood hostile environments - before soils evolved.

Vannier on Ghilarov 

According to Russian entomologist/I'm not first to consider insects evolved through the soilFrom Vannier (1987). 
"M.S. Ghilarov (1949) advocated a theory on the evolution of insects through the soil as a special medium: the soil consisting of three phases (solid, liquid and gaseous) has as an environment many peculiar properties. As the air in the soil is almost always saturated with water vapour, and films of water are present around solid particles, the conditions of existence in this medium are a character intermediate between aquatic and epigeion. So for many groups of terrestrial invertebrates the soil was a transitional medium in the course of their evolution from aquatic to terrestrial habitats (Ghilarov 1959). Professor Ghilarov based his arguments on the ecophysiological adaptations of soil animals, in particular of insects that were different from those of epigeion forms. These include a high integumental permeability in soil dwellers, skin respiration, in tracheate forms spiracles operating without a closing mechanism, relatively little resistance to cold, little sensitivity to increased CO2 concentration, saprophagy like aquatic animals (detritophagy), and external insemination (spermatophores). According to Professor Ghilarov, this double nature of soil insects - the combination of properties common to aquatic dwellers and terrestrial forms - is due to remarkable properties of soil as a transitional medium. Working on the behaviour of microarthropods (Acarina, Collembola) towards soil water....Soil, like other hygroscopic porous bodies, is a medium intermediate between the hydrosphere and atmosphere. This unique ecological milieu permitted the development of amphibious organisms, and I proposed that the term porosphere be used to describe this environment.

The late Professor Ghilarov was a great entomologist and an enthusiastic pedozoologist. He was also a far-sighted specialist who studied the evolution of terrestrial faunas. In the course of the VIIIth International Colloquium of Soil Zoology at Louvain-laNeuve (Belgium), he reviewed the main physiological adaptations which have permitted soil invertebrates to become independent of aquatic conditions and to engage in the conquest of terrestrial environments (Ghilarov 1983). For more than 35 years Ghilarov advocated a theory on the evolution of insects through the soil as a special medium: the soil consisting of three phases (solid, liquid and gaseous) has as an environment many peculiar properties. As the air in the soil is almost always saturated with water vapour, and films of water are present around solid particles, the conditions of existence in this medium are a character intermediate between aquatic and epigeion. So for many groups of terrestrial invertebrates the soil was a transitional medium in the course of their evolution from aquatic to terrestrial habitats (Ghilarov 1959).

Vannier: "I extended this idea to all porous bodies having an internal surface which fulfills the same role; even before the formation of modern soils in the Cretaceous era with the first appearance of flowering plants (Angiosperms) I acknowledge that Professor Ghilarov's view based on ecophysiological considerations was of great help .
 So he says 'formation of modern soils in Cretaceous era"..hmm that is from around 145mya..flowering plants  of course need...SOIL which must have predated.# that period..but my theory  is more accurate.. 

Perhaps a page on Extinction..

There was one of the big five extinctions in 356 mya, that seems to have stopped the movement of fish to land - were four footed fish on river/sea banks before that..but how does it impact on land colonisation or as I call it soil formation?
Charlie Clutterbuck,
Aug 12, 2019, 1:06 AM