The Small White, along with the Large White, can claim the title of "Cabbage White" that is the bane of allotment holders all over the British Isles although the damage caused by this species is significantly less than that of the Large White. This is one of the most widespread species found in the British Isles and can be found almost everywhere. It is relatively scarce in northern Scotland but has been seen as far north as Orkney and Shetland. This species is also known to migrate to the British Isles from the continent, sometimes flying in great swarms, augmenting the resident population in the process.
It is believed that this butterfly can fly up to 100 miles in its lifetime although, undoubtedly, most butterflies will only travel a mile or two. Evidence of the mobility of this species comes from a misguided introduction in Melbourne in 1939. 3 years after its introduction, the species had reached the west coast of Australia some 1,850 miles away in only 25 generations. This species has been a pest in the continent ever since.
Zeller (1847) described the summer generation of P. rapae as f. aestiva, which is more heavily marked with black and more richly coloured. The nominate form, f. rapae, is used to describe the spring generation.
This species was first defined in Linnaeus (1758) as shown here (type locality: Sweden). Adults of the spring brood have generally lighter markings than those of the summer brood.
There are generally 2 generations each year, with 3 generations in good years. Second brood adults have noticeably darker markings that those of the first brood. First-brood adults typically emerge in late April, peaking around the middle of May and gradually tailing off through June. The second brood, which is always stronger than the first brood, starts to emerge in early July. However, in good years, the second brood may emerge in late June and give rise to a third brood.
The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.
This species is found in a wide variety of habitats and can turn up almost anywhere, including gardens, allotments, parks, meadows, open grassland, and hedgerows.
The primary larval foodplants are Crucifers (various) (Cruciferae family (various)) and Nasturtium (Tropaeolum majus). Charlock (Sinapis arvensis), Garlic Mustard (Alliaria petiolata), Hedge Mustard (Sisymbrium officinale), Hoary Cress (Lepidium draba), Wild Cabbage (Brassica oleracea) and Wild Mignonette (Reseda lutea) are also used.
Adults feed primarily on Thistles (Cirsium spp. and Carduus spp.). Bird's-foot Trefoil (Lotus corniculatus), Bluebell (Hyacinthoides non-scriptus), Bugle (Ajuga reptans), Daisy (Bellis perennis), Dandelion (Taraxacum agg.), Fleabane (Pulicaria dysenterica), Greater Stitchwort (Stellaria holostea), Hawkweeds (Hieracium/Hypochoeris), Ragged Robin (Lychnis flos-cuculi), Ragwort (Senecio jacobaea), Red Campion (Silene dioica), Red Clover (Trifolium pratense) and Sanfoin (Onobrychis viciifolia) are also used.
This highly-mobile butterfly can turn up almost anywhere and is a familiar sight in gardens across much of the British Isles where it is attracted to various nectar sources, in particular those with white flowers.
Aberration in this species chiefly occurs in the upperside ground colour and the extent of the black markings. As usual in the 'whites' many aberrations are unique to either male or female specimens, and being seasonally dimorphic some aberrations are also specific to the generation or 'brood'.
Certain ground colour aberrations in this species have been found mainly in Scotland and Ireland. The aberration flava has been recorded chiefly in Ireland and specimens from the country were bred en masse by entomologists such as Newman in the early 20th century. These aberrations were popular with breeders and collectors and while scarce now in the wild a large number of these impressive forms can be found in collections.
There are 39 named aberrations known to occur in Britain.
Click here to see a full list of aberrations for this species.
Eggs are laid singly, normally on the underside of a leaf. Foodplants in sheltered areas are preferred and gardens often provide ideal locations as a result. The eggs are pale when first laid, but gradually turn yellow and ultimately grey prior to hatching, this stage lasting as little as a week.
The larva eats its eggshell on hatching, and subsequently feeds on the foodplant, leaving tell-tale holes in the leaf which increase in size as the larva grows. On cabbages and other brassicas, the caterpillar moves into the heart of the plant as it grows. Older larvae tend to rest on the midrib of a leaf where it is well-camouflaged. This stage lasts around 3 weeks.
The pupa is usually formed away from the foodplant, such as on a fence, tree trunk or building, and is supported by a silk girdle and the cremaster. The pupa may even be found in greenhouses. The pupa has two main colour forms - green and brown - and those that do not go on to produce adults in the same year overwinter.
The Green-veined White and Small White are most easily distinguished by their undersides, where the Green-veined White has pronounced markings along the veins which are absent in the Small White.
Green-veined White (left) and Small White (right)
It is much more difficult to distinguish between the Green-veined White and Small White based on the upperside, since the amount of marking is highly variable. In general, the veins of the Green-veined White are more pronounced. Also, the marking at the apex of the forewing of a Green-veined White often extends down the along the edge of the forewing and is not contiguous. The marking at the apex of a Small White never extends down the edge of the forewing and is unbroken.
Green-veined White male (left) and Small White male (right)
In general, the Large White and Small White can be distinguished based on size. However, there are occasions when a "small" Large White flying with a "large" Small White causes confusion. In terms of uppersides, a distinguishing feature is the black marking at the apex of the forewing. This is generally more vertical than horizontal in the Large White, and more horizontal than vertical in the Small White.
Large White (left) and Small White (right)
Distinguishing these two species based on their underside is a little more difficult. Aside from size, there is sometimes a hint of the upperside markings where, again, those at the apex of the forewing can give an indication of the species.
Large White (left) and Small White (right)
No videos are currently available for this species.
Click here to see the distribution of this species overlaid with specific site information. Alternatively, select one of the sites listed below.
|Ashampstead Common, Aylesbeare Common, Darley, Devil's Ditch, Fleam Dyke, Glenarm, Hounslow Heath LNR, Howardian Local Nature Reserve, Kinghorn Loch Path, Lavernock, Malling Down, Mayford Pond, Meanwood Park, Millenium Arboretum, Moors Valley Country Park, Moss Field, Mynydd Marian, Nupend Wood, Old Down, Basingstoke, Roudsea Wood NNR, Strumpshaw Fen, Tophill Low, Viking Field/LesleySears, Winsdon Hill|
The status of this species is relatively-stable and so this widespread and common butterfly is not currently a species of conservation concern.
The table above shows the distribution and population trends of species regularly found in the British Isles. The distribution trend represents a comparison between data for the periods 1995-1999 and 2005-2009. The information provided is taken from the Butterfly Conservation report The State of the UK's Butterflies 2011. The UK BAP status is taken from the UK Biodiversity Action Plan (UK BAP) (2007 review).
The following links provide additional information on this butterfly.
The species description provided here references the following publications: