Butterflies of
Europe
Black-veined White
Aporia crataegi
LINNAEUS, 1758
Family - PIERIDAE
subfamily -
PIERINAE
Tribe - PIERINI
introduction
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habitats |
lifecycle |
adult behaviour
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Aporia crataegi, Krasno Polje,
Velebit mountains, Croatia
( image
courtesy © Peter Bruce-Jones ) |
Introduction
There are 30 species of
Aporia, the majority of which are limited to Tibet,
Mongolia and China. Aporia crataegi is by far the
commonest and most widespread member of the genus, being found from Spain and
North Africa, across Europe and temperate Asia to Kamchatka and Japan.
Black-veined Whites were
also once common in southern England, where there were at least 50 resident
colonies, reinforced by regular immigrations from Europe. In the early 1920s
however the butterflies suddenly disappeared. Various theories for the
extinction were put forward, including unsuitably mild winters, parasitism, bird
predation and the use of herbicides in orchards, but the real explanation
remains unknown, and despite several attempted reintroductions the species has
failed to re-establish itself in Britain.
Aporia crataegi, Ravni Dabar,
Velebit mountains, Croatia ( image
courtesy © Peter Bruce-Jones )
Habitats
This species
is found on scrubby grassland, along roadsides, around woodland and field edges,
in sub-alpine woodland / hay meadow mosaics and other open habitats where the
foodplants grow. It tends to be most abundant in drier habitats, and can be
found at elevations between sea level and about 1600m.
Lifecycle
The eggs are laid in batches of between 50-200 on the underside of
leaves of blackthorn bushes Prunus spinosa
or
more rarely on hawthorn Crataegus (
Rosaceae ).
They are spindle-shaped, with numerous vertical ribs, and bright
yellow in colour.
The caterpillars hatch in July, feed for a while, and enter
hibernation in September. They awaken and resume feeding in March
or April. Throughout the early instars they live within a communal
web of silk, spun on the foodplant. As they grow they split into
smaller groups and spin new webs, continuing their gregarious
existence until the final instar when they split up and become
solitary.
When fully grown the caterpillar is sparsely covered in soft
hairs, and is black above, with orange-brown subdorsal stripes.
The lower half of the body is off-white.
The chrysalis is attached vertically by the cremaster and a silken
girdle to a twig or branch, on or near the foodplant. It is white,
heavily suffused with yellow, with black streaks on the thorax and
wing cases, and black spots all over the abdomen.
The adults fly from May to early August.
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Aporia crataegi, Meribel les
Allues, la Vanoise, France |
Adult behaviour
Both sexes nectar at a wide variety of flowers including ox-eye
daisies, scabious, thistles, clovers,
vipers bugloss, self-heal, valerian, lavender and various vetches.
Males commonly visit sources of mineral-rich moisture such as
urine-tainted soil, dung, and the edges of shallow stagnant pools.
In Siberia the butterflies often aggregate in thousands to drink
at the edges of shallow streams.
I have not observed the courtship, but have often found copulated
pairs late in the morning, sitting on flowerheads. The butterflies
are quite nervous - if disturbed while mating they take flight,
with the male carrying the female. They usually resettle a short
distance away on another flower head.
It is interesting to note the roosting behaviour of this species.
In Provence e.g. I visited a meadow on a warm sunny day in August
when hundreds of crataegi could be seen flying. The next morning
however saw a dramatic change in the weather - the wind direction
changed, funnelling the freezing gale-force winds of the Mistral
through the valley. I visited the meadow again, hardly expecting
to be able to find a single butterfly, but was amazed to discover
that almost every flower-head held a cluster of 3 or 4
Black-veined Whites, each clinging desperately to their plant,
where they remained until the winds dropped and temperatures rose
again late in the afternoon.
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