What do the early stages look like?
The eggs are greenish at first but turn orange. They are laid on flower stalks. The caterpillars are an olive-yellow when they first emerge with a relatively large and darker-coloured head. They grow rapidly through the five instars (from 1.5mm to 30mm) with the total larval stage only lasting about 3-4 weeks. In the middle stages they develop a grey-green colouration but by the final instar they are bright green with tiny black points all over the body from which hairs grow. Orange-tip caterpillars are cannibalistic in their early stages and there is usually only one caterpillar left per food-plant. The pupa is an unusual elongated shape, attached by a silk pad and silk girdle. Initially they are green, but become a more camouflaged light brown with time.
What do the caterpillars eat?
As with the other whites, the orange-tip caterpillars eat plants in the Brassicaceae family especially
cuckooflower Cardamine pratensis in damp meadows and
garlic mustard Alliaria petiolata along road verges and ditches. They also use hedge mustard
Sisymbrium officinale, winter-cress
Barbarea vulgaris, charlock
Sinapis avensis, pennycress
Thlaspi arvense, tower mustard
Turritis glabra and hairy rock-cress
Arabis hirsuta among others.
1. In gardens they will eat dame's violet
Hesperis matronalis, and both annual and perennial honesty
Lunaria annua and
L.rediviva.
Flowers they take nectar from
Adults feed primarily on bluebell, brambles, bugle, cuckooflower, dandelions, garlic mustard, greater stitchwort, ground-ivy, hawkweeds, ragged-Robin, red campion and vetches.2.
How are they doing?
Orange-tips are not a species of concern. The 2022 State of UK butterflies report shows a statistically significant 26% increase in numbers since 1976 compared with an increase of 10% in the 2015 version. They spread considerably in Scotland over the past 30 years but the distribution appears steady at present.3.
Other interesting facts
The beautiful green pattern on the underside of the hindwing is an optical illusion as it is formed from a combination of yellow and black scales in a similar way to the green-veined white.
A subspecies britannica has been described for some British specimens based on wing shape, but with only 0.3% of records attributed to this form 4. ,which shares the same distribution as the typical subspecies, it seems doubtful that a subspecies distinction is valid.
References
3. 2022 State of UK butterflies
report
Page written by Judy Skinner, reviewed and compiled by Steve Head