Family - PIERIDAE
subfamily - PIERINAE
Tribe - PIERINI
© Adrian Hoskins
There may be as
many as 34 species of Pieris worldwide,
although the status of some is uncertain. The commonest and most
widespread species is rapae, which was
originally restricted to Europe and temperate Asia but has been
introduced by man to North America, Africa, s.e. Asia, Australia and
The genus can be divided into 2
groups - the 'Large' Whites brassicae,
& tadjika; and the smaller species
mannii, napi and
melete which have more rounded
fore-wings. Some taxonomists place the latter group into a distinct
genus Artogeia, citing characteristics
including chromosome number, ovipositing behaviour and larval
Small White is one of the most widely distributed species in the
world ( the most widespread of all being the Painted Lady ). It
occurs throughout Europe, in north Africa, throughout the Middle
East and eastward across temperate Asia to Japan. It was introduced
to Canada in 1860, and to the USA in 1866. During the 20th century
it was introduced to numerous other countries including Bermuda,
Australia, New Zealand and Iceland.
This is a strongly migratory species which can be found in almost
any habitat with the exception of the highest mountain peaks.
However it is far commoner in the vicinity of gardens, allotments
and farmland where crucifers ( cabbage, sprouts etc ) are grown.
The pale yellow, skittle-shaped eggs are laid
singly on the underside of the leaves of cabbages and sprouts
Brassica, garden nasturtiums
Tropaeolum, and less often on
Sinapis or other wild crucifers. Often
several eggs will be laid on the same plant, or even under the same
leaf, but these are laid by different females, or by successive
visits by a single female.
The dull green, slightly hairy caterpillars feed
diurnally on the leaves of the foodplants. On cabbages the young
larvae bury deep into the heart of the plants, inflicting serious
damage to the developing leaves. When older they feed openly,
nibbling a mass of irregularly shaped holes out of the leaves, but
leaving the midrib and tougher veins intact.
serious commercial pest of cabbage crops but do less damage than the
larvae of the Cabbage moth Mamestra brassicae.
The larvae are heavily
predated by harvestmen and beetles, and by birds including sparrows,
tits, warblers and thrushes. Also, in common with most other
caterpillars they are attacked by various parasitoids, the main
culprit in this case being
chrysalis has several colour forms, ranging from pale green to a
dirty brownish white, with dark dots on the abdomen. It is attached
either vertically or horizontally to fence-posts, brick walls, or
the underside of shed roofs, windowsills and other sturdy materials.
© Adrian Hoskins
Early in the day, or
in overcast conditions, the butterflies bask with their wings
half-open, reflecting solar energy onto the thorax and abdomen, which
are covered with dark hair-like scales that assist in rapid heat
absorption. In sunny conditions they usually keep their wings shut
when resting or nectaring, but copulated pairs usually rest with wings
© Adrian Hoskins
patrol around cabbages and other crucifers, waiting to intercept
females. When the sexes meet, the male flies up and down in front of
the female, enticing her to settle, and then settles beside her. He
then uses his outspread wings to force the female to lean to one side,
and bends his abdomen round to copulate with her. Immediately after
joining, the pair fly a short distance to settle on the foliage of a
nearby plant. If a male intercepts an unresponsive female, she spreads
her wings and raises her abdomen as a rejection signal.
The butterflies often
congregate in sheltered gardens to oviposit, or to seek nectar at
cultivated flowers, particularly favouring buddleia. In the
countryside they often gather to nectar at patches of hemp agrimony,
marjoram, thistles, knapweeds, yellow rattle, or valerian.
They roost singly,
usually on the upper surface of the leaves of bushes or herbaceous
plants, even in rainy weather.