UK Butterflies

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Bath White

Pontia daplidice

PON-tee-uh da-pli-DY-see

Wingspan
48 - 52 mm

Checklist Number
58.009

Bath White

Pontia daplidice

PON-tee-uh da-pli-DY-see

Wingspan
48 - 52 mm

Checklist Number
58.009


This is an extremely scarce immigrant to the British Isles and, in some years, is not seen at all. However, on occasion, it does appear in large numbers, such as the great immigration of 1945. The first specimen was recorded in the British Isles in the late 17th century. Between 1850 and 1939 there were very few records, with only a few years reaching double figures. The exception was 1906 when several hundred were supposedly seen on the cliffs at Durdle Door, Dorset, although these records are considered suspect. The great years for this species, however, were between 1944 and 1950, with over 700 seen in 1945, mostly in Cornwall. This species has been extremely scarce ever since with less than 20 individuals recorded since 1952. It is believed that this species cannot survive our winter although some offspring resulting from the 1945 invasion may have survived into the following year. In the British Isles the species was potentially capable of producing 2 or 3 broods in good years.

The butterfly was originally known as "Vernon's Half Mourner" after the first recognised capture by William Vernon in Cambridgeshire in May 1702, although earlier records are now known. However, the common name of this butterfly comes from a piece of needlework that figures this species, supposedly showing a specimen taken in or near Bath in 1795, and the name seems to have "stuck". This species is a rare migrant to the British Isles. Although most records come from the south coast of England, this species has been reported as far north as Lincolnshire and Yorkshire in England, and also in County Wexford, south east Ireland (a record from 1893).

This species was first defined in Linnaeus (1758) as shown here (type locality: Southern Europe and Africa).

Description to be completed.

This species is a rare migrant to Britain and/or Ireland.

1.2 Rare Migrant

This species prefers open habitats of any kind and, on the continent, will even breed on derelict sites.

No conservation action is relevant for this species.

Adults are typically seen in the British Isles in July, August and September.

This is a highly mobile species, the last mass immigration occurring in 1945. Given the similarity of this species to other, more-common, whites, it is probably overlooked and therefore under-recorded.

Description to be completed.

Eggs are laid singly on the foodplant and are yellow-green when first laid, gradually turning orange. Eggs found in the British Isles in 1945 were laid on the flower heads of Wild Mignonette, Hedge Mustard and Sea Radish. Eggs hatch in approximately a week.

"This butterfly lays its eggs on various species of mignonette such as Reseda odorata and R. lutea, and also on some other plants. They are laid singly on both the blossom and leaves, mostly on the under surface of the latter. Those laid upon the bloom of R. odorata exactly resemble the anthers in size and colour. On October 3rd, 1901, the author received from Hyeres, France, four P. daplidice females, but only one arrived alive in a very feeble condition, but after feeding on sugar and water for about fifteen minutes it considerably revived. It was then placed upon mignonette (R. odorata) in the sun, when it at once started depositing; in half an hour three dozen eggs were laid on various parts of the plant. Again, on October 10th, three more living females were received from the same locality; these deposited a few eggs the same day as their arrival and continued laying daily whenever the sun shone sufficiently. The egg is 0.86 mm. high, clan elongated conical shape, widest at the middle and slightly concave directly below the apex; the extreme summit is flat and finely pitted in the centre; there are thirteen or fourteen longitudinal keels (usually thirteen), all running the entire length, and about thirty transverse ribs; both these and the keels are of glistening whiteness. When first laid the egg is a light yellowish-green; it gradually turns yellower, and on the third day assumes an orange colour, and finally on the fourth day attains a deep orange. The egg is wonderfully similar to that of Euchloe cardamines, but has not the transparent elongated apex, and all the keels in daplidice run to the summit, whereas in cardamines some vanish before reaching it. Just before hatching the colouring becomes much duller, and the little larva shows clearly through the glistening shell. All the three dozen eggs laid on October 3rd hatched on October 13th, remaining ten days in the egg state." - Frohawk (1924)

The larva feeds during both day and night and this stage typically lasts between 3 and 4 weeks.

The primary larval foodplant is Cabbage family (Brassicaceae).

1st Instar

"The larva directly after emergence is very small, measuring only 1 mm. long; it is uniformly cylindrical, and very much like cardamines. The head is shining black and beset with a number of fine bristles. The body is of a rich raw-sienna colour; the segments are bi-lobed transversely; on the side of each segment are five large, olive-brown, blunt tubercles with pale centres, each bearing a long, stiff, black, cleft-knobbed spine. These are situated over the body similar to cardamines; others are also placed on the claspers. The spiracles are black. The dorsal surface is smooth, but granulations gradually develop on the sides, and the ventral surface is strongly granulated, where they form small points. Just previous to the first moult it measures 3 mm. long." - Frohawk (1924)

2nd Instar

"Several moulted for the first time on October 18th, the first stage occupying five days. After the first moult, ten days old, it measures 5 mm. long. The ground colour is a pale lilac-grey, mottled with dark olive; a pale medio-dorsal line is formed by the mottlings and uniting in the centre; there are four longitudinal lemon-yellow stripes, two on either side, one being sub-dorsal, which is the broadest and brightest, and the other spiracular. On the side of each segment are nine large, shining, olive-black tubercles, six above and three below the spiracle, and five small ones, placed between the two sub-dorsal stripes. As in the previous stage, each tubercle emits a black bristle with a cleft knob, which carries a minute globule of clear white liquid. The head and spiracles are similar to the first stage, the legs are black and the claspers tinged with lemon-yellow. They rest in a straight attitude. No traces of cannibalism could be detected in these larvae, in this respect differing greatly from cardamines." - Frohawk (1924)

3rd Instar

"Several moulted the second time on October 23rd , the second stage also lasting five days. A large number died just before and after the second moult, owing to the dull and cold weather. When thirteen days old, after second moult, it measures 11 mm. long. It is uniformly cylindrical. Excepting the head, which is ochreous blotched with black, and the brighter colouring and better defined pattern due to its increased size, it is similar in all respects to the previous stage." - Frohawk (1924)

4th Instar

"The third moult occurred on the evening of October 27th, the third stage occupying only four days. After the third moult, nineteen days old, it is 15.9 mm. long. All the colours are brightly and clearly defined; the stripes are rich gamboge-yellow; the medio-dorsal line is slightly paler than the broad dorsal slate-blue band, which is chiefly formed by a border of dark mottlings along either side. The larger wart-like tubercles are very conspicuous, black and shining. All the spines (bristles) are in this stage simple and finely pointed, and many of the smaller ones are whitish. The longest are slightly curved and have the apical half white. The head is coloured like the body, the yellow spiracular stripe extending over the face. A few succeeded in moulting the fourth time during the last days of October, and one moulted on November 3rd, but on that day a dense fog set in, and lasted until the evening of the 8th. This, accompanied by frost at night, proved fatal to all the larva. They were in various stages, many being quite small." - Frohawk (1924)

5th Instar

"After fourth and last moult, fully grown, it measures 25.4 mm. in length. The body is cylindrical, tapering at the ends; the segments are sub-divided by six transverse wrinkles, which number only two in the first stage. The ground colour is a clear lilac; a very fine and faint medio-dorsal line, and four rich yellow longitudinal bands, two on each side; the first is sub-dorsal and widest, broken up on the fourth wrinkle with pale grey, the second band is spiracular, and extends over the side of the head; it is also broken up into a series of markings by the central third portion on each segment being of a pale greenish grey, which encloses the very pale, inconspicuous spiracle. At the base of each clasper and leg is an ochreous-yellow blotch, forming a disjointed third band. The whole surface is densely sprinkled with black shining warts, varying greatly in size, each bearing a fine simple spine, the majority being shining black, those on the ventral surface are whitish; the head of similar colouring to the body, and likewise covered with warts and spines. The legs are mottled black and whitish; the lilac ground colour of the body is mottled with dusky spots, on which are placed the smallest black warts. Excepting the first stage the larva is similar in pattern throughout. The above description of the full-grown larva is from a specimen found by Mr. Raine at Elyeres feeding on wild mignonette (Reseda lutea), who very kindly sent it direct to the author; it arrived on November 16th, and, after feeding on that and the following day, it spun up for pupation on the 18th, and pupated on the 20th November." - Frohawk (1924)

The pupa is often formed on stems of the foodplant, but also away from the foodplant on fences, buildings or other flat surfaces. The pupa is supported by a silk girdle and the cremaster.

"The pupa measures 19 mm. long. In shape it exactly resembles P. napi, having a pointed beak, a strongly angulated thoracic dorsal keel, sub-dorsal abdominal angular projections, and a basal wing point. The colour is a very pale lilac-grey, with creamy-buff sub-dorsal and spiracular stripes corresponding with those of the larvae; a medio-dorsal whitish line, dotted with black at the segmental divisions along the abdomen. The entire surface is sprinkled with minute black dots, black markings on the keel, and a black streak on either side of the beak. The wings are buffish, with black speckled nervures. Like other Pieridae pupae, it is attached by the cremastral hooks to a layer of silk, and a silken cincture round the waist. A female emerged (from this pupa described) on December 11th, 1901." - Frohawk (1924)