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Giant dragonflies once roamed Earth’s skies. New research upends the textbook theory of why they went extinct

The Conversation · · 691 words · By Edward Snelling; Roger S Seymour

The article discusses research on ancient giant insects, explaining how their size was influenced by high oxygen levels in the past. It argues that modern flying insects could theoretically achieve similar sizes due to advancements in their respiratory systems, though such insects do not exist today due to ecological factors.

open_in_new Read the original article: https://theconversation.com/giant-dragonflies-once-roamed-earths-skies-new-resea…

analyticsAnalysis

0%
Propaganda Score
confidence: 95%
Low risk. This article shows minimal use of propaganda techniques.

fact_checkFact-Check Results

18 claims extracted and verified against multiple sources including cross-references, web search, and Wikipedia.

schedule Pending 8
help Insufficient Evidence 7
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verified Verified By Reference 1
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“Insects first took to the skies about 350 million years ago, some 200 million years before birds first flapped their wings.”
CORROBORATED
Multiple independent sources confirm insects first appeared in the Carboniferous period (358-299 million years ago) and birds evolved later. Web search results and Wikipedia entries consistently report this timeline.
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wikipedia NEUTRAL — The most recent understanding of the evolution of insects is based on studies of the following branches of science: molecular biology, insect morphology, paleontology, insect taxonomy, evolution, embr…
https://en.wikipedia.org/wiki/Evolution_of_insects
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wikipedia NEUTRAL — Insects (from Latin insectum) are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, tho…
https://en.wikipedia.org/wiki/Insect
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wikipedia NEUTRAL — Megaloblatta is a genus of Neotropical cockroaches in the family Ectobiidae. Species in this genus are 4 to 9.7 cm (1.6–3.8 in) long and can have a wingspan of up to 20 cm (8 in); the world's largest …
https://en.wikipedia.org/wiki/Megaloblatta
+ 3 more evidence sources
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“By the end of the Carboniferous period, 300 million years ago, some flying insects had become gigantic. Huge dragonfly-like insects called griffinflies had wingspans of 70cm – five times the size of the largest modern dragonflies.”
CORROBORATED
Evidence from web search and Wikipedia confirms griffinfly (Meganisoptera) had wingspans up to 70cm, five times modern dragonflies. Multiple sources independently describe this size.
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wikipedia NEUTRAL — Meganisoptera is an extinct order of large dragonfly-like insects, informally known as griffenflies or (incorrectly) as giant dragonflies. The order was formerly named Protodonata, the "proto-Odonata"…
https://en.wikipedia.org/wiki/Meganisoptera
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wikipedia NEUTRAL — Namurotypus is an extinct genus of griffinfly with a single described species Namurotypus sippeli. It is the only member of the family Namurotypidae. It inhabited the large swamps of the Carboniferous…
https://en.wikipedia.org/wiki/Namurotypus
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wikipedia NEUTRAL — The Odonatoptera are a superorder (sometimes treated as an order) of ancient winged insects, placed in the probably paraphyletic group Palaeoptera. The dragonflies and damselflies (which are placed in…
https://en.wikipedia.org/wiki/Odonatoptera
+ 3 more evidence sources
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“These giant insects lived in a time when Earth’s atmosphere contained more oxygen than it does today: around 30%, compared with the modern 21%.”
VERIFIED BY REFERENCE
Wikipedia and web search results directly state atmospheric oxygen levels were 30-35% during the Carboniferous period (compared to 21% today), matching the claim.
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wikipedia NEUTRAL — The Mississippian ( MISS-iss-IP-ee-ən), also known as Lower Carboniferous or Early Carboniferous, is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of t…
https://en.wikipedia.org/wiki/Mississippian_(geology)
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wikipedia NEUTRAL — The Carboniferous ( KAR-bə-NIF-ər-əs) is a geologic period and system of the Paleozoic era that spans 60 million years, from the end of the Devonian Period 358.86 Ma (million years ago) to the beginni…
https://en.wikipedia.org/wiki/Carboniferous
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wikipedia NEUTRAL — The Carboniferous rainforest collapse (CRC) was a minor extinction event that occurred around 305 million years ago in the Carboniferous period. The event occurred at the end of the Moscovian and cont…
https://en.wikipedia.org/wiki/Carboniferous_rainforest_colla…
+ 3 more evidence sources
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“Because large flying insects lived in a time of high oxygen levels, scientists have proposed that they required these high external oxygen levels to power the rapid burn of energy during flight.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the claim about oxygen requirements for flight.
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“In new research published today in Nature, we studied the muscles of dozens of modern flying insects and made a surprising discovery: there is no reason the griffinfly could not survive in today’s atmosphere.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the claim about griffinfly survival in modern atmosphere.
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“Flying takes more energy than running or swimming, because a flapping flier must constantly work against gravity to remain in the air.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the energy comparison between flight and locomotion.
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“The highest rate of oxygen consumption per gram by any known tissue occurs in a flying bee.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the oxygen consumption rate claim.
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“Oxygen is supplied to insect flight muscles through the 'tracheal system', a tree-like branching system of air-filled tubes that lead to the smallest branches, called 'tracheoles', where oxygen moves into the muscle tissue.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the tracheal system description.
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“In modern insects, oxygen levels near the oxygen-consuming mitochondria that power the flight muscle are very close to zero. This implies that the structure of the tracheal system was just adequate to supply sufficient oxygen.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the oxygen levels near mitochondria claim.
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“The idea that the structure and function of the insect tracheal system limits body size has prevailed for the past 30 years and appears in educational textbooks.”
INSUFFICIENT EVIDENCE
No evidence found in web search or Wikipedia to support or refute the 30-year textbook hypothesis claim.
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“We initially thought all an insect had to do to increase its oxygen delivery would be to increase the number of tracheoles. After all, this is where oxygen is supplied to the mitochondria.”
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“To be sure the locust was not exceptional and to properly understand the effect of body size, we measured 44 species of flying insects of different body masses and metabolic rates. The project required five years and 1,320 transmission electron micrographs.”
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“But the results were essentially the same: the tracheoles occupied only about 1% of the cross-sectional area of the flight muscles regardless of body size. In contrast, the blood-filled capillaries in the flight and cardiac tissue of some birds and mammals occupy about 10% of the area.”
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“This shows there is plenty of scope to increase the number and volume of tracheoles without weakening the muscle. So the structure of the tracheal system is not an important constraint on body size.”
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“Evidence from developing insects shows insects can grow more tracheoles in flight muscle in lower oxygen levels, and they pass this trait to their offspring.”
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“The conclusion is that the body size of flying insects has never been limited by the structure or function of their tracheal systems.”
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“There is no physiological reason why insects the size of griffinflies could not fly in today’s atmosphere. And yet they don’t exist today.”
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“The simpler reasons may be that larger animal species are more prone to extinction than smaller ones – and 300 million years ago, the griffinfly had no bird or mammal predators to watch out for.”
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info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.