Anyone who's observed Clouded Yellows coming in from the English Channel at places like Budleigh Salterton would find flaws in that account. Better still, if anyone has chased a resolutely migrating Clouded Yellow for a mile or so before giving up exhausted ~ as I did sometimes in my youth ...
... they never stop even when coming in from the sea but carry on inland at speed and up and over buildings rather than try to find a way around obstructions. Observed these things many times.
Even something as frail as say a Holly Blue, which is half the body bulk of say the much more powerful Chalkhill Blue, can really get a move on when flying non-stop along a woodland ride resolutely in what appears to me like a migration. Maybe they do which could explain the fluctuations in their numbers from year to year although my observations indicate any variances in Holly Berry production some years may have something to do with that. I have found an ovum on a flower and berry less Holly. I doubt the minute newly hatched larva would be able to eat any of the tough older growth in the absence of softer flowers, berries or new leaves or shoots.
Monarchs cover huge distances during migration both ways but, are not using wing muscles all the time and so spend less effort doing so than say a Clouded Yellow which I have not seen gliding ever ~ unless I do not pay sufficient attention.
No two butterflies are ever identical and there is brood colour variation too. Maybe certain broods of Monarchs are of a slightly different or darker colour and that brood is the one which is better equipped for longer flights due to brood/seasonal/larval feeding variation rather than colour differentials. Needs a much more comprehensive appraisal.
Article wrote:
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Researchers believe dark winged butterflies, such as a Speckled Wood (left) are better flyers than light-winged types like this Cabbage White
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In a race, my money would not be on the Speckled wood ..
... Where would your money be ?
Article wrote:"researchers believe .....suggesting an association"
No certainty there...
Then there are the really powerful butterfly flyers like Agrias and Prepona which are my all time favourites of the butterfly world and include some of the most incredibly beautiful. Very powerful flyers but, as far as know, do not fly vast distances for migration. Most Agrias and Prepona have dark colours.
Heat production in flight.
Years ago when breeding Death's Head Hawk moths, surely our most powerful lepidopteron, their powers of flight even in a large cage absolutely amazed me. I had a couple of pairs in a large net cage. The plan to obtain some natural pairings and that was successful. The cage was about two cubic metres in volume with a small potted Privet Bush for the females to lay their ova on. I kept the cage in a warm room and as the last light of dusk started to disappear, I was passing the room and heard a noise not heard before. Hard to describe but it was like a powerful well silenced small engine with a Brm, brm brm brm continuous noise. I carefully opened the door and the noise was much louder and I saw one of the powerful moths hovering in the cage. That was the noise. the moths powerful wing beats was making it. I watched it for about a minute in that very precise and controlled continuous hover. Amazing ! However, it would disturb another pair which I did not want to be prematurely seperated so I removed the hovering male moth. I got a surprise when I picked it up. , it's closed wings and thorax between my finger and thumb. It was not warm, it was HOt to the touch.
By the way, these moths have a very sharp pin like part in that thorax area on both sides which can give a nasty prick for the unwary picking up a resting moth. When much younger without access to reference books, for years I never understood why this moth had such an unusual proboscis compared to other nectar feeding moths and butterflies. Years went by and watching one of the BBC's excellent natural History programmes, David Attenborough described the pictured Huge Honey bees nest high up in a tree. Both the bees, which if I recall he said were the largest Honey Bees in the world and their honeycomb nests out in the open high up in trees exposed and covered only in bees for protection. Filmed at night, a hovering Death's Head Hawk Moth suddenly appeared and then plunged into those hundreds of huge honey bees with their very powerful sting ~ correction ~ thousands of bees ~ and disappeared from sight. Only to emerge a little later and fly away having tanked up on the honey.
I vaguely remember reading about that odd shaped, stubby proboscis with reports that the moth had been seen and found in commercial bee hives. That 'tool' of a proboscis is ideal for penetrating the soft bees wax honeycomb to extract the honey. I fed my captive moths of a 50% dilute mix of clear honey. The need to feed to become sexually mature as do many butterflies.
Breeding the Great Purple Emperor, Japan's National Butterfly ( Have the UK got one ? ), before taking their very first flight and sometimes other flights, they vibrate their wings for several minutes, with a firm foothold to stop taking off. reminds me of a helicopter warming up before take-off...
Fascinating to watch especially the males with their purple colour flashing with every wing stroke. I have once or twice observed our own PE males doing this in captivity ... for the benefit of a female it shared the cage with. They can be very determined when ... aroused! I picked one of these Great PEs up before it took off and that had a warm thorax, but not as hot as that Hawk Moth's one when I picked that up. These chance observations are rarely observed. They are very interesting as they add to our knowledge and underline, just how little we really know. The life histories of some of the largest animals on the plant and in the oceans are still unknown!
