camerart's picture

Largest Dragonfly

Hello everybody,

In the mid 1950s, I was feeding our Hens, where they roamed free range in the size of an allotment. From memory I saw a Dragonfly, that cruised 6ft from the ground, and flew over the Hens. All of the Hens spread their wings 1/2 out and lowered themselves down to the ground, I presume they thought it was a bird of prey. I told a friend of mine and said that it was about 6inches long with a similar wings pan and its body was as thick as my little finger. He said impossible and explained the largest British Dragonfly known. Can you tell me please, was this an exaggeration on my part, from the impact of the event, or could it have been anywhere near true?

Best wishes, Camerart

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Peter Allen's picture

The largest British (and

The largest British (and Europaean) dragonfly is Anax imperator, the Emperor Dragonfly.This has a wingspan of 105mm or so and an overall length of around 80mm. The abdomen has a width of about 4mm - considerably less than the smallest adult little finger! So I'm sorry to say that your memory has exaggerated somewhat!! The largest of the Anax dragonflies is Anax walsinghami from the USA which is 115mm+; Anax tristis, an African species is 110mm, but even these are not little-finger-thick......

Hampshire Dragonfly recorder
Hampshire & IOW Wildlfe Trust

camerart's picture

Ok, Thank you. I suppose many

Ok, Thank you.

I suppose many memories are not quite as we remember.

I did hear that size can be changed by different environments, like high Oxygen etc, perhaps mine had lived a healthy life.

Peter Allen's picture

Meganeura moneyi

There was indeed an "oxygen blip" in the Carboniferous Period when there existed some massive dragonflies. The increased partial pressure of oxygen meant that much larger body masses could receive oxygen. Meganeura moneyi had a 27 inch wingspan - certainly big enough to frighten your chickens - and you also!!

Hampshire Dragonfly recorder
Hampshire & IOW Wildlfe Trust

camerart's picture

WOW!, could this be

WOW!, could this be replicated today?

anonymous spotter's picture

Sadly, no -

As stated above by Mr Allen, this could only happen because the oxygen content of the atmosphere was much higher. The "passive" arthropod respiration system is nowhere near as efficient as our muscle-driven lungs (the rigid exoskeleton forces it on them), and is a major limitation on the size they can grow to.

JonathanWallace's picture

I agree with the other

I agree with the other comments made regarding the largest dragonflies.
It is worth saying, though, that Anax imperator and the Aeschna species of hawker dragonflies are still very impressive creatures, and if one was not familiar with them it would be quite easy to magnify one in the memory!

Jonathan Wallace

edward_ammonite's picture

I agree too

I would say, though, that drgonflies on the wing always seem a lot larger than they are. Particularly Emperors which have a great deal of presence, and are fairly powerful fliers for their size. It's always a surprise to me when you find them close up and sitting still that they're not as big as they seem.