Header photo by Ben Rees

Photo above left by Lauren Teate

Photo above right by Dave Williamson

The Green-veined White is a medium sized white butterfly which is very easily confused in flight with Small Whites, Large Whites and female Orange Tips. However the closed wing view of a resting butterfly is usually distinctive, with fuzzy, grey-green veins against a mainly yellowish background (although background colour is quite variable). Upperside wings have less well-marked dark veins in males and more strongly marked veins in females. Upper forewings have dark wing tips broken by white strips of varying width.

Size can vary considerably from half-sized miniature specimens with a similar wingspan to Common Blues, to 'giants' close in size to Large Whites. The summer brood adults are usually bigger than spring brood adults.

This is a very variable species and there’s some debate about how it should be split into subspecies and the ranges of the different subspecies. English specimens are either subspecies sabellicae Stephens 1828, or septentrionalis Verity 1916. At some point north of Yorkshire the English subspecies gives way to a more strongly marked subspecies thomsoni Warren 1968, but the full range of thomsoni is under debate.

Although widespread, the species is localised by a need for damp and humid areas. Typical habitats are marshes, canal and river banks, slow moving streams, lush ditches and damp meadows. The butterfly also visits sheltered woodland edges and rides where males can often be seen patrolling quite high up along the lines of trees. it is also found along road and rail verges, especially where hedges or trees give rise to shadier damper sections but is not as common in gardens as other Whites.

lt uses a wide range of cruciferous plants, but its main foodplants tend to be lady's smock Cardamine pratensis, Garlic Mustard Alliaria petiolata and Hedge Mustard Sisymbrium officinale.

Adult males often land on the muddy edges of puddles or on animal droppings to suck up sodium and essential minerals.

There are colonies at Spurn NNR which seems a somewhat untypical habitat comprising a line of sand dunes sandwiched between the Sea and the Humber Estuary. There are also colonies found up to 300m in sheltered valleys west of Sheffield and on moors above Huddersfield and Ripponden (all VC63), and up to 450m in the Stang forest (VC65). The species is one of the most common in the Yorkshire Dales and on the North Yorkshire Moors where additional rainfall gives rise to plenty of suitably damp areas.

The species is resident and there are usually two overlapping broods (April to June and June to August); with a small partial third brood in warmer years.

Higher areas may only produce one brood (June and July) and single brooded populations are thought to remain single brooded even in warmer years which is something that could be researched further, especially in the Dales (VCs64/65). Single brooded populations are also thought to be more sedentary than their lowland cousins. Although Green-veined Whites are less mobile than Small and Large Whites, the double-brooded variety does wander and, although not generally considered migratory, occasional long-distance movements may occur. Sudden build-ups sometimes happen at traditional migration hotspots along Yorkshire's east coast and this also deserves more study.

Drought years are known to be a problem, but it has shown itself able to spring back within a year or two of any losses. Nonetheless, global warming is of potential concern, particularly for the one-generation upland form.

By tetrad count this species is the second most widespread Yorkshire species after the Small Tortoiseshell. Site counts can be up to 250 at Spurn NNR.

It is found throughout British Isles except Shetland. Outside Britain it is found from north west Africa to northern Scandinavia and eastward across Asia and North America.

Eggs are laid singly and well scattered on the undersides of leaves of cruciferous plants such as those listed above and they hatch after about a week.

Larvae eat their eggshells before eating foodplant leaves and have five instars. They pupate after two to three weeks and occur in brown, green or mixed colour forms and are hidden away near ground level and therefore very difficult to find. Every pupa has the possibility of being thin-skinned (if produced when there are 12 or more hours of daylight, or thick-skinned (when daylight hours are waning, with less than 12 hours in the day). Thin-skinned pupae go on to produce another generation within as little as ten days, whilst thick-skinned varieties will hibernate for several months. Up to 40% of pupae appear to be killed by a virus during hibernation.

Males usually emerge a few days before females and patrol habitats in search of mates. They shower potential partners with a chemical, which smells like lemon verbena, and is strong enough to be picked up by humans. This action is usually followed by a chase and then by pairing. Finally, the male smears another chemical on the female, which dissuades other males from pursuing his female. However, this effect only lasts a few days so the female later goes on to attract and mate with other males, apparently to get more smears of anti-male chemical, which help to provide her with quiet periods in which she can concentrate on laying eggs.

The species is not under threat.

Over 80 aberrations have been described. Ab sulphurea Schoyen has pale citrus-coloured upperwings and might be mistaken for a Pale Clouded Yellow.

With thanks to The Butterflies of Yorkshire edited by Howard M Frost