At this time last year, on a quiet warm evening, one of the
most striking moth sightings we have seen was a lek or mating gathering of Ghost
Moths. The satin white wings of the
males shimmered in the twilight as many scores of them made their swaying flight about
eighteen inches above the flower meadow . More and more appeared, but within
twenty minutes they were disappearing as they searched and found the brown winged
females resting in the herbage below.
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| Flower meadow where lek occurred at twilight |
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| Mating Ghost Moths |
A few summers ago when camping on the South Brittany coast,
we saw another mating flight, also at twilight. Hundreds of Cockchafers were in lumbering flight just over the tops
of willow bushes growing at the head of the dunes. Again this lasted for little
more than half an hour before they too disappeared.
Even more dramatic than the mass flighting of winged ants we
sometimes see in Britain, like the one that happened simultaneously in many
parts of the country in thundery weather last summer, is the flighting of
winged termites in the tropics.
I quote from our log: Sep.3rd 1995. Barkley Tableland, West Queensland:
“Yesterday we decided to stop on these wide open grasslands
so we left the road and drove down the fenceline for a way, and made camp.
It was still 94F and the oppressive heat
unbearable so in desperation at about
5pm we walked back along the fence to make the air move around us a little. The
van soon looked a forlorn dot in the vast straw-coloured plain. Walking back to
the van, before we disturbed a big mob of Brahmin cattle crowding round a water
tank fed by a clanking windmill, we noticed we were making a sheltered shadow for
great clouds of flying termites. There were two kinds, one with a fat pale
orange body, and others which were small and black. Female and male? They were
pitching in great numbers on our backs and when we got back to the van we were
staggered by the vast swirling cloud of them in the lee of the van. Huge
numbers had drowned themselves in our water bucket and bowl where I’d put the
spuds I’d peeled for the evening meal. They got in our eyes, our noses, ears,
mouths, and they drove me into the van where I spent the next half hour
slaughtering them. Tony cooked the one-pot I’d got ready and by twilight they
had gone.
A few big fat drops of rain fell from the heavy dark cloud above.
This morning there was a brisk northerly wind carrying the smell of rain on damp earth;
.....somebody had been lucky. Perhaps
this was what had triggered the termites’ flight yesterday.”
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| Termite plain |
Mass emergences are always amazing.
Many years ago we were in a small town on the banks of the Loire
and we saw the gutters and nooks and crannies between the buildings were full
of piles of the corpses of Mayflies. We must have just missed the fabled
flighting of these insects, but years later when on a boat in one of the many
waterways making up the delta of the Danube in Romania, we saw another sort of
Mayfly emerging from the slow-flowing water.
I quote from Tony’s
entry in our log:
“We happened upon a considerable natural phenomenon:
swarming Giant or Long-tailed Mayflies (Palegenia longicauda) One of the party
had spotted a few to start with. They were flying, keeping pace with us and
then dropping back to start again, low over the muddy water. But then, over the
next hour or so, numbers increased until
there were untold scores of thousands, and the water surface was thick with
them. Passengers and crew were hanging over the side in wonder. Danny our
co-leader shouted to Mary to bring her net and by hanging precariously well
over the side he managed to bring a specimen aboard. He needn’t have bothered as
the swarm became a cloud and they were crash-landing on us, on the deck, like
stranded flying fish.
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| Long-tailed or Giant Mayfly, Danube Delta |
The body was about two inches long, with black eyes, a pale
cream thorax, grey body and two yellow
tail streamers, about two inches long in the males and a bit shorter in what we
took to be the females. Their wings were opaque and almost silver, quite short
and rounded.
Small flocks of Terns
and Starlings were feeding on them in a couple of places as we motored slowly
along the streamway between a thick fringe of willows. I watched a Little Egret
catching any that came within reach as it stood on a log and waited. The
Starlings were a bit like a Peregrine in a flock of pigeons ; they didn’t know
which one to go for as they hawked through them. “
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| Giant Mayfly emerging from the water |
These Mayfly , the largest in the world, are apparently rare
now, occurring in only a few rivers in Eastern Europe.
Once when camping in woodland in SW Australia we noticed
oily-looking black patches several feet across, on the thin herbage all around
us. Looking closely we saw these patches were formed by myriads of small black
flies, crowded so closely there was no ground to be seen between them. The oily
effect was due to the lustre of their wings.
We didn’t see them go, but when we came back from a walk
several hours later, they were gone without trace.
The massing of Locusts happens in two stages. The first is
of the immature stage, the flightless
‘hoppers’ which emerge in
favourable conditions and gather in vast numbers. They look like small brown
grasshoppers. We have seen great carpets of them moving across the ground, both
in Greece and again in Australia. They will in time develop after more skin
changes, into winged adult Locusts, and when these adults swarm in some
years they become one of the ‘Plagues of
Egypt’.
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| Locust swarm in the air |
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| Tree largely defoliated by locusts |
We were initially puzzled when in Queensland we heard a
subdued but insistent rustling and crackling. It was a vast swarm of locusts
working their way through the savannah landscape of smallish trees growing in
open grassland. They clustered in the trees till the branches drooped under the
weight of the insects clotting every twig as they voraciously munched every
leaf. You could hear them chewing and their frass (droppings) pattered down to
the ground below where trains of ants were gathering it and carrying it back to
their underground nests. The locusts’ wings rustled and shone silvery when the
trees were stripped bare and they flew on, to land in the untouched trees ahead.
They seemed to favour certain kinds of trees over others. Most sought after
were Bauhinnias or Butterfly Tree. A mob
of Black Kites was swooping over them, picking off insects in their path.
Sometimes you see the dispersal of these mass gatherings of
creatures. A few years ago, walking down
the track from the Ridge Reserve in Luckett Woods,
going steeply downhill towards the Tamar and the narrow flat strip with
its damp drainage ditches alongside the river,
we met, toiling up the steep
hill, a crawling host of tiny toadlings, no bigger than the end of my thumb.
There were literally tens of thousands all moving up and away from the river.
They were not only on the track, but laboriously clambering up among the dead
leaves and twiggy litter under the trees alongside. We had to be careful where we put
each foot as we moved downhill, against the tide. It was towards the end of our
walk and I couldn’t face following them back up in the interests of science, to
see how and where they started to fan out and scatter, as I suppose they would.
I have wondered ever since!
We saw a similar happening of a carpet of toadlings
spreading away from the shore of a shallow lake up in Gulf Country in northern
Queensland. As ever, no camera!
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| Roosting beetles in the shade of a rocky overhang. |
Some insects gather together in large numbers to aestivate,
or roost in cool sheltered places to avoid the summer heat. We found the
astonishing sight of probably thousands of a lovely iridescent smallish beetle crowded together on the leaves of
a plant growing in the damp shady underhang of the rocky cliff of a small gorge
we were exploring in the Northern Territory.
Later on that same trip saw the
aestivating roost of a great number of Australian Crow Butterflies which were clinging to the leaves and twigs of a
grove of small trees near a waterhole near Broome in the north of Western
Australia. They were restless and easily disturbed This roosting isn’t true
hibernation.
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| Summer roost of Australian Crow Butterflies |
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| Australian Crow butterfly |
An important cultural ceremony of one of the Indigenous
tribes in New South Wales was based on the mass migration of a Moth.
The Bogong Moth of Australia.
Migrates
in spring from further north and west to aestivate in close masses in the caves
and rocky crevices of the Australian Alps in the southern part of the Great
Dividing Range. The moths were particularly nutritious as they have thick
fat-rich bodies and played a significant role in the people’s bush tucker.
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| Australian Alps where the Bogong moths spend the Australian summer. |
But the most famous of all these mass movements is the migration
of the Monarch Butterfly from Canada and the northern States, to escape the
cold winter and aestivate in the forests of Mexico, hanging in vast numbers
from the trees. They return north the following spring, stopping to produce
another generation partway on their journey.
In North America apparently the caterpillars feed exclusively on the
Milkweed plant which grows further north and which gives this butterfly the
alternative name of The Milkweed.
It is a handsome powerful butterfly and specimens can be found especially on the Cornish coast
on occasions, presumable blown off course during their migration.
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| Bristly Silkweed in Algarve, Portugal |
We have seen
a small colony in The Algarve in southern Portugal where the caterpillars feed
on the Bristle-fruited Silkweed which is
related to the Asclepias or Milkweeds , knows as such because of the copious
milky sap exuding from the cut stems. It is a poison, and the Monarch butterfly
carries this poison in its body, rendering it unpalatable to predators.
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| Monarch caterpillar |
And we found a caterpillar in New South Wales
back in Oct ’89 but I forget what it was feeding on. ( I was told later it would be on Silkweed). The butterfly, known
for obvious reasons, as The Wanderer in Australia , has been known there since
1871. The Silkweed plant is as big a wanderer as
the Monarch. It originates in South Africa.
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| The Monarch Butterfly |
