White Admiral Watch: Rollo’s Story

A tale in tweets following the life of Rollo, a White Admiral butterfly caterpillar, offspring of Camilla

As Rollo slumbers a brief interlude follows…

We return to the star of our show…

Rollo’s close neighbour catches a chill…

Spring returns to the wood…

White Admiral Watch pays tribute to Eric Carle, author of ‘The Very Hungry Caterpillar’…

But not all is well…

The reason for Rollo’s delayed development becomes clear…

Search #WhiteAdmiralWatch on Twitter for more!

White Admiral Watch

White Admiral butterfly metamorphosis: from larva to prepupa to pupa to imago.

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.

28 May

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 (Limenitis camilla) 5th instar caterpillar on honeysuckle (Lonicera periclymenum).

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.

31 May

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.

White admiral (Limenitis camilla) prepupa suspended from honeysuckle (Lonicera periclymenum).

2 June

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)

White admiral (Limenitis camilla) pupa suspended from honeysuckle (Lonicera periclymenum). Day 1.

7 June

The pupa darkened up a little in the next few days, its undulations mimicking the Honeysuckle leaves quite convincingly.

White admiral (Limenitis camilla) pupa suspended from honeysuckle (Lonicera periclymenum). Day 6.

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.

23 June

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.

White admiral (Limenitis camilla) pupa suspended from honeysuckle (Lonicera periclymenum). Day 22.

24 June

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.

White admiral (Limenitis camilla) pupa suspended from honeysuckle (Lonicera periclymenum). Day 23 (AM).

By 5pm that afternoon my ‘White’ Admiral was now distinctly black!

White admiral (Limenitis camilla) pupa suspended from honeysuckle (Lonicera periclymenum). Day 23 (PM).

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)

White admiral (Limenitis camilla) pupa suspended from honeysuckle (Lonicera periclymenum). Day 23 (PM).

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.

25 June

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!

White admiral (Limenitis camilla) imago newly hatched. Day 24.

Camilla luxuriated in the warm morning sunlight streaming through the oak canopy, slowly expanding her glorious wings as she clung to the vacant ‘exuvia’.

White admiral (Limenitis camilla) imago newly hatched. Day 24.

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.

White admiral (Limenitis camilla) imago shortly before first flight.

And then 8 minutes later, at 11:20 she flew for the first time… and was gone!

Video showing newly emerged White Admiral (Limenitis camilla) butterfly drying its wings before takeoff.

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.

White admiral (Limenitis camilla) butterfly nectaring on bramble flowers.

To be continued…

Related links

Toads on roads

Common toad (Bufo bufo) crossing a road at night on migration to breeding pond. Sussex, UK.

After emerging from hibernation in early spring common toads (Bufo bufo) migrate back to their breeding ponds at night. Sometimes this involves crossing busy roads and many toads are sadly hit and killed by passing cars.

Each year volunteers working with charities such as Froglife and local Amphibian and Reptile Groups attempt to ferry migrating toads, frogs and newts to safety at known crossing points.

Toad crossing signage. Sussex, UK.
Common toad (Bufo bufo) juvenile recovered at road crossing on spring migration. Surrey, UK.
Toads retrieved from road in a bucket

Male toads grasp females in a position known as ‘amplexus’ as they attempt to fertilise her eggs. Often a mating pair can be found together before they reach the nearest pond. When this happens males hitch a free ride!

Common toads in amplexus while crossing a road on spring migration

Related links

Inside flies

I was delighted to see my work featured in Erica McAlister’s new book on diptera: ‘The Inside Out of Flies’, published by London’s Natural History Museum last month.

Cover of book on flies
The Inside Out of Flies by Erica McAlister

The photograph in question shows hundreds of eggs laid by a member of the horse fly family (Tabanidae).

Horse fly eggs featured in The Inside Out of Flies

Erica uses the reproductive strategy of horse flies to illustrate r/K selection theory:

r-selected species are seen as more opportunistic and are able to propogate more quickly if the environment is suitable, whereas K-strategists spend more time investing in a few offspring to give them whatever competitive advantages they can to prosper in what are often already crowded niches

The original image from my archive is shown below:

Horse fly eggs (Tabanus cordiger?) on salad burnet (Sanguisorba minor) stem. Surrey, UK

Related links

Purbeck mason wasp

In the UK the rare Purbeck mason wasp (Pseudepipona herrichii) is found only in the Isle of Purbeck, Dorset.

The female excavates a nest burrow in bare ground on heathland and later seals it with moistened clay.

Wasp with excavated soil

Purbeck mason wasp (Pseudepipona herrichii) excavating nest burrow on heathland. Dorset, UK.

She stocks her burrow with the larvae of a small moth which feeds mainly on bell heather.

Purbeck mason wasp: prey

Purbeck mason wasp (Pseudepipona herrichii) with Acleris hyemana moth larva prey at nest burrow entrance. Dorset, UK.

The adults chew distinctive holes in the heather flowers to obtain nectar which their short tongues could not otherwise reach.

Wasp drinking from heather

Purbeck mason wasp male nectaring on bell heather. Dorset, UK.

The Purbeck mason wasp is thought to rely solely on the larvae of Acleris hyemna, but in 2017 I photographed this female provisioning her nest with what appears to be the moth Acleris notana.

Purbeck mason wasp: prey

Purbeck mason wasp (Pseudepipona herrichii) with moth larva prey (Acleris notana?) at nest burrow entrance. Dorset, UK.

One small victory for citizen science?

Related links

Fly orchid pollinator

The fly orchid (Ophrys insectifera) is usually found on chalk and limestone soils in open deciduous woodland and scrub, but is also recorded from grassland and chalk-pits. It is rare in the UK and even at known locations can be difficult to spot.

Fly orchids

Fly orchids in woodland clearing. Surrey, UK.

Fly orchids are in flower between May and June. At this time they attract male digger wasps (Argogorytes mystaceus) with a scent which closely resembles the female wasp’s pheromone.

Males attempt to copulate with the orchid and during this process pollinia become attached, which may be carried to the stigma of another flower, completing pollination.

Digger wasp pseudo-copulating with fly orchid

Digger wasp attracted to fly orchid flower.

Male digger wasp pseudo-copulating with fly orchid

Male digger wasp pseudo-copulating with fly orchid.

Digger wasp with fly orchid pollinia

Fly orchid pollinia attached to the head of male digger wasp.

I was finally lucky enough to observe and document this behaviour in the Surrey Hills earlier this year.

Find out more

Butterfly Conservation

Advancing conservation science through public engagement on digital platforms

Working for the local branch of Butterfly Conservation I developed an online system to document sightings of butterflies submitted by members of the public in Dorset.

This ‘citizen science’ project encourages engagement in nature conservation and adds to our knowledge of these vital environmental indicator species.

In 2018 more than 44,000 butterflies were successfully recorded using this method.

Capture

Initially butterfly spotters are directed to a web form which collects personal info, location details including grid reference, and species observed.

dbc-recording-form-01
Butterfly recording form: recorder info
Butterfly recording form: site details
Butterfly recording form: site details

This information is then inserted into the Dorset Branch web sightings database.

Verify

Local experts are given password-protected access to a record management interface on the branch website. Recently submitted butterfly sightings can be reviewed and verified with a single click.

dbc-recording-verify-01
Butterfly record verification

Questionable records can be studied in more detail and recorders contacted to clarify information as necessary.

Butterfly record management view
Butterfly record management view

Interpret

Verified records are instantly published to the branch website, using a number of graphical representations for easy interpretation.

Butterfly data: map
Butterfly data: map
Butterfly data: tree chart
Butterfly data: tree chart
Butterfly data: calendar
Butterfly data: calendar
Butterfly data: bar chart
Butterfly data: bar chart
Butterfly data: pie chart
Butterfly data: pie chart
Butterfly data: Gantt chart
Butterfly data: Gantt chart

Archive

Butterfly sightings received via the website are archived online for the public to explore in greater depth.

dbc-recording-archive
Butterfly data: archive

Share

Casual sightings received via the branch website provide a useful snapshot of butterfly activity in Dorset. But for research purposes it’s necessary to combine them with data from formally structured butterfly transects and other recording schemes within the region and nationally.

Website data is exported to the national society’s database annually. National butterfly recording cycles run for 5 years, at the end of which an ‘atlas’ is produced, showing the updated distribution of species and population trends.

To encourage recording in under-represented areas an interactive ‘White Holes’ map is published on the branch website. This combines data from the national database with more up-to-date regional web sightings.

Butterfly data: White Holes map
Butterfly data: White Holes map
Butterfly data: White Holes map detail
Butterfly data: White Holes map detail

It’s possible to use this map on a GPS-enabled mobile device to locate the nearest White Hole for observation. A list of previously recorded species for each 1km square is also presented.

Over the past 4 years this recording system has gathered more than 180,000 individual butterfly records, contributing to our understanding of these beautiful creatures and the changing environment they inhabit.

Drone mapping

Drone mapping
Drone mapping using a consumer level DJI Spark drone.

Experiment in environmental monitoring using a small consumer drone

For a few months now I’ve been experimenting with the (non-commercial) use of a small camera drone for environmental monitoring. The quality of the resulting images and the unique perspective it offers have been pleasantly surprising. Its potential applications at relatively low cost are impressive I think.

Red Hill Henge

The site of this Scheduled Ancient Monument lies east of the A3 in Surrey and just north of Junction 10 on the M25 motorway.

Map of Red Hill Henge
Red Hill Henge scheduled Ancient Monument (1007905). © Crown Copyright and database right 2018.

‘Making the countryside pay’

In late 2017 Surrey County Council, in collaboration with Surrey Wildlife Trust, decided that this Site of Special Scientific Interest (SSSI) would be a suitable venue to pilot their commercial felling operations in the county.

A felling licence issued by the Forestry Commission permitted them to extract 30% on 2 occasions over a 10 year period. Upon visiting the site however the impact at ground level looked far more extensive than I would have expected.

Stacks of felled timber
Felling operations on Wisley & Ockham Commons SSSI

Concerned that contractors may have exceeded their remit and damaged the Scheduled Ancient Monument in the process I mapped an area to the north of the site, flying the drone in parallel lines at a height of 60 metres with the downward-facing camera set to take pictures at intervals every few seconds.

Cloud view

With the help of DroneDeploy’s internet cloud software I then stitched the resulting 139 overlapping images together to create an orthomosaic map layer.

Drone map
Area mapped by drone at Red Hill Henge in Surrey.
Orthomosaic map imagery
Orthomosaic detail from drone imagery at Red Hill Henge.

Tracks left by the contractor’s heavy machinery can be seen running across the circular ‘henge-like’ earth bank feature.

Switching to the Normalised Difference Vegetation Index (NDVI) imagery analysis clearly shows the difference between live green vegetation and felled woodland.

NDVI map
Normalised Difference Vegetation Index (NDVI) analysis of felled woodland.
NDVI map
Normalised Density Vegetation Index analysis of felled woodland.

Extra dimension

To help peopIe unfamiliar with the site to visualise the monument in context I then generated a 3D model from the visual point data using DroneDeploy’s online competitor, Pix4D.

3D model of ancient monument
3D model of Red Hill Henge generated from drone imagery.

For terrain features and dense canopy this technique works well, but it struggles to accurately represent isolated trees and finer features. Without resorting to an expensive aerial LiDAR platform it would be difficult to achieve better results however.

Bright Spark

The little drone done good on this occasion, and with minimal disturbance to this historically and environmentally sensitive site ironically.

DJI Spark drone
DJI Spark drone. Photo: Ralph Clark.

Oak Galls: Wasp vs. Plant

Oak trees are home to more than 30 species of gall wasp. The larval stage of these insects induce the plant to produce abnormal growths, known as galls, which enclose and protect them as they develop.

Oak gall wasp larva IV

Galls come in a variety of fantastical shapes, each unique to particular species.

Oak marble gall

Marble galls

Hard woody spherical galls up to 25mm in diameter on the oak stems. Initially green but later become brown.

Created by: Andricus kollari

Oak apple gall

Oak Apple Gall II

These galls have a spongy texture and are brownish white, tinged with pink.

Created by: Biorhiza pallida

Common spangle gall

Common Spangle Galls II

Yellowish gingery brown disc-shaped galls on the underside of oak leaves in late summer and early autumn.

Created by: Neuroterus quercusbaccarum

Silk button spangle gall

Silk Button Surfeit

Golden brown discs with a depressed centre on the underside of oak leaves in late summer through to early autumn.

Created by: Neuroterus numismalis

Knopper gall

Knopper gall

The acorn becomes a ridged woody structure. The gall is initially yellowish green and sticky but later greyish brown.

Created by: Andricus quercuscalicis

Cherry gall

Oak Cherry Galls

Yellowish green or red spherical galls up to 20mm in diameter on the underside of oak leaves in late summer and autumn.

Created by: Cynips quercusfolii

It gets complicated…

Oak gall wasps have complex life cycles, with alternating generations that are either sexual with males and females, or asexual with females only.

The two generations of wasp often produce different types of gall on different parts of the tree, and in some species the two generations alternate between native and non-native species of oak.

Oak Gall Wasps VI

There are also wasps which specialise in injecting their eggs into oak galls. Their larvae then eat the resident eggs or larvae before they emerge.

Chalcid Wasp

The example above shows a type of Chalcid wasp investigating a fresh oak marble gall.

Find out more