The White Admiral is a nationally uncommon woodland butterfly which can be found rapidly swooping, gliding or skimming along the tracks in and around Dene Park, Clearhedges Wood and probably some surrounding woodland as well, in mid-summer, mid-June to August. They are really majestic butterflies, if you do get to spot them! Most of the rest of the year is spent as the caterpillar, feeding on honeysuckle.
Description
In flight these are largely dark brown (females) or blackish (males) large swooping butterflies, both sexes with bold white markings.
This particular butterfly is probably dark enough to be a male:
The underside of the butterflies is rather a surprise, being much more varied in colour, mainly brown and white, with blue-grey patches next to the rather similar body:
Dene Park, 05-07-2017
Distribution
I have only seen this butterfly in fairly well-developed areas of woodland in Kent, with substantial trees, such as those in Dene Park, or on the outskirts of Clearhedges Wood. I suspect it can also be found in the surrounding but private woodlands such as Golden Stable Wood and Carroty Wood and will perhaps wander even further in the parish on occasion. However, the strips of woodlands in the south of the parish along the River Medway just don't "feel" right for them. It is probably present in reasonable numbers in Dene Park, but may spend much of its time invisible to observers high up in the woodland canopy, drinking aphid honeydew or just basking on oak leaves. In the European Collins Guide it is noted as having a preference for bramble blossom, and I have seen it nectaring from bramble flowers at Lullingstone.
Here is what looks like a female, drinking aphid honeydew from leaves:
Lullingstone
Although White Admirals are noted for nectaring on bramble, here is a photo of one (perhaps a male) nectaring in Dene Park on an umbellifer, possibly Angelica,
Dene Park
White Admirals can be found in woodlands, and currently appears to be spreading, across Kent, including Tudeley Woods, Mereworth Woods, Lullingstone Country Park, the Bredhurst Woods, Orlestone Forest and the Blean. However in the UK the White Admiral is very much a southern insect, rarely found much to the north of the Midlands and Lincolnshire. On a global scale it is a very widespread butterfly, commonly found across much of central Europe and temperate Asia to the Far East.
Life cycle
The caterpillar food-plant is trailing non-flowering wisps of honeysuckle, which grows in very reasonable numbers twining around branches on the trees in Dene Park. The females seek these out, laying single white eggs on the top surface of the honeysuckle leaves. The tiny first stage caterpillar tends to camouflage itself with silk and its own droppings, but then feeds unprotected until it folds a leaf into a "hibernaculum" stuck to a shoot where it overwinters. This process is metabolically aided by dehydration, and glycerol accumulation in response to colder temperatures.
The caterpillar continues to feed in the spring, changing to a largely green spiky final stage, until it forms a cunningly camouflaged green and gold chrysalis suspended from the honeysuckle shoot, finally emerging as an adult from mid-June to July.
Warm and dry Junes encourage rapid development in these final stages, leading to better adult numbers emerging over the next few months, as the ever-present risk of predation by birds is then more rapidly escaped.
Oddities
This butterfly likes shady maturing to mature woodland, even doing very well in coniferous woodland in the younger stages. It does not seem to do so well in the better lighting of regularly coppiced woods, where on the other hand the other woodland Fritillaries are more likely to thrive. Its numbers and range decreased greatly in the later 19th century due to poorer weather and extensive ("peak?") coppicing of woodlands, but the butterfly recovered in the late 20th century to roughly its previous historically known levels - over the last few hundred years, since some idea of records existed. However, it has declined significantly again on the national scale over the last twenty years, since the start of the 21st Century, despite the increase in mature woodlands, the reason for this being rather uncertain, and opposite to the apparent distributional trend in Kent.
Parasites and Predators
The last couple of caterpillar stages and the chrysalis stages are known to be heavily predated by birds.
Priority species fact sheet.
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