In Sussex during the COVID-19 epidemic of 2020 I followed one very special butterfly through pupation to emergence
The White Admiral (Limenitis camilla) is a large woodland butterfly which glides effortlessly along forest rides. Its numbers in the UK have rebounded since the First World War, possibly due to the cessation of coppicing which, unusually, has benefited this species since its larvae require Honeysuckle growing in shady woodland.
My first, long awaited, encounter with ‘Camilla’ came on 28 May when my many searches of Honeysuckle vines finally bore fruit and this magnificent creature suddenly greeted me.
White Admiral caterpillars are entirely dependent on Honeysuckle for their survival, feeding on its leaves through all five larval instars and hibernating within their folds.
At more than 2 cm in length this was a fifth and final stage caterpillar, exotic in appearance compared to the majority of British butterfly larvae, adorned with branching red spines along its back and resting in a raised serpentine position.
When I returned 3 days later Camilla was already preparing to pupate, hanging beneath a Honeysuckle leaf, suspended from her hind claspers attached to a pad of silk.
48 hours later the pupa was now fully formed, with two prominent horns on the head and an odd protrusion further back.
“The pupa bears a close resemblance to a profile portrait of Punch.”
– Frohawk (1924)
The pupa darkened up a little in the next few days, its undulations mimicking the Honeysuckle leaves quite convincingly.
For the next two weeks few visible changes occurred and the weather turned cold and wet. A marauding army of small birds came and went, leaving Camilla thankfully undisturbed.
Around Day 22 the folded wing veins became a bit more pronounced beneath the pupal case and its body seemed to have plumped up a bit. Warm, sunny weather had returned to the woodland glade.
Revisiting on the morning of Day 23 I found Camilla had darkened up overnight, turning from green to brown, signalling that ‘eclosion’ of the adult butterfly was imminent.
By 5pm that afternoon my ‘White’ Admiral was now distinctly black!
From a different angle the butterfly’s wing structure and patternation could clearly be seen.
“Before emergence it turns to a bronze-black all over, losing almost all the metallic lustre of silver-gilt; the white wing markings of the imago show pale amber colour through the pupal skin.”
– Frohawk (1924)
I was hopeful the adult butterfly would emerge that evening and so remained until well after dusk, but as it grew dark I was forced to return home for the night.
Back on site very early next morning I was relieved to discover that the big moment had yet to arrive.
Camilla remained suspended from the Honeysuckle leaf until 09:11 on Day 24 when she suddenly popped out of her chrysalis in the blink of an eye, annoyingly while my back was briefly turned!
Camilla luxuriated in the warm morning sunlight streaming through the oak canopy, slowly expanding her glorious wings as she clung to the vacant ‘exuvia’.
By 10:50 her wings were fully expanded and at 11:12, two hours after emergence, she clambered nimbly up onto the Honeysuckle leaf which had supported her pupa through sun and rain, heat and cold, for the past 24 days. It would now become her launching pad.
And then 8 minutes later, at 11:20 she flew for the first time… and was gone!
Except that I strongly suspect she hung around…
I only witnessed one other adult White Admiral in the wood that summer. The individual photographed below frequented Bramble blossom within metres of Camilla’s hatching site, sunning itself on the woodland floor nearby and alighting on Honeysuckle, likely assessing suitable spots to lay her eggs for the next generation of White Admiral caterpillars to emerge.
To be continued…
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The puss moth caterpillar’s ‘eyes’ are only for display
A colleague working for Surrey Wildlife Trust kindly guided me to the location of this wonderful puss moth caterpillar (Cerura vinula) yesterday. A pair of them were contentedly grazing on aspen leaves.
Puss moth larvae feed on poplar, willow, or here on aspen
In adult form the furry grey and white moth flies at night between the months of May and July. The larval form looks much more exotic. The gawdy pink ring around its face gives the puss moth a very distinctive appearance.
Head end of puss moth caterpillar
If disturbed the puss moth caterpillar extends two whip-like appendages from its tail end and flails them around to deter attackers. It’s a bizarre and unexpected thing to witness.
Puss moth caterpillar with extended ‘tails’
‘Tail’ detail of puss moth larva
It also has the ability to squirt formic acid from its thorax if further provoked, but I didn’t try that!
Shortly before pupation the caterpillar will change to a fetching shade of orange, and then again to purple.
It spins a cocoon of silk around itself and uses bits of tree bark as camouflage to stay hidden for the winter. The resulting cocoon is one of the strongest constructed by any UK moth.
I will have to return to see if I can find it in its various rainbow stages of development.
It’s true that the lucky winners in life morph into fabulous winged creatures which transcend their earthy origins, but a great many of their brethren seem destined to become nothing more than a convenient snack for any number of passing creatures.
Walking along the Purbeck coastal downland in mid summer I discovered a particularly unpleasant variation on this theme.
I was hoping to photograph some Adonis blue butterflies – a local speciality – but became mesmerised by a collection of tiny cocoons fastened to a grass stem. The more I looked, the more cocoons I found, but all appeared to have been vacated.
I couldn’t think what they might be, until additional exploration eventually uncovered their unfortunate victim nearby: a burnet moth caterpillar, seemingly tied to the stake:
Burnet moth caterpillar parasitised by wasp larvae
This time the larvae were all too evident, as they appeared to be burrowing out of the caterpillar’s skin!
Further research reveals a fascinating tale of nature’s indifferent ingenuity:
The perpetrators in this instance are a species of Braconidae wasp which lay their eggs inside caterpillars.
When they hatch the larvae consume the caterpillar from the inside, but are careful to spare vital organs in order to keep their victim alive. Eventually the larvae cut their way out using specially adapted sharp mouthparts. When they emerge they immediately spin cocoons attached to the caterpillar.
Recent studies suggest that the larvae influence the caterpillar’s behaviour to remain in place and guard the cocoons. Thus brainwashed, the creature may even spin it’s own silk around the cocoons to further protect them. The wasps later hatch and the zombified caterpillar dies of hunger. Ain’t life great!
The Braconidae wasps don’t get it all their way however, as another variety of Ichneumon wasp parasitises the Braconidae pupae inside their own cocoons.
I found an example of this behaviour a bit further along the same stretch of coastal downland. The cocoons had been deserted by their caterpillar protector for some reason, which left them exposed.