UK Butterflies
Building a Community of Responsible Butterfly Enthusiasts in Britain & Ireland
Building a Community of Responsible Butterfly Enthusiasts in Britain & Ireland
Wingspan
♂ 52 - 56 mm, ♀ 52 - 62 mm
Checklist Number
58.011
The Pale Clouded Yellow is an extremely rare immigrant to the British Isles, and was first recognised as occurring in England in the late 18th century. Historically, this species was considered to be an irregular migrant that could be relatively-common in some years but not seen at all in others. Between 1826 and 1950 there were 8,500 records, with over 2,000 records in 1900. Good numbers were also seen each year from 1945 to 1949. However, such numbers have not been recorded since and this species is now considered one of our rarest migrants. This species has been recorded mainly in the south of England, the south of Ireland and the Channel Islands. However, individuals have been found as far north as Cumbria and even Scotland. In 1947 an individual was found in the Inner Hebrides. Those that reach our shores are believed to have come from northern France or central Europe.
| Family: | Pieridae | Swainson, 1820 |
| Subfamily: | Coliadinae | Swainson, 1820 |
| Tribe: | Coliadini | Swainson, 1827 |
| Genus: | Colias | Fabricius, 1807 |
| Subgenus: | ||
| Species: | hyale | (Linnaeus, 1758) |
Description to be completed.
This species is a rare migrant to Britain and/or Ireland.
| 1.2 Rare Migrant |
The haunts of this butterfly are similar to the Clouded Yellow, which includes coastal cliffs, open downland, and fields containing Lucerne or Clover, the larval food plants.
No conservation action is relevant for this species.
In the British Isles, this species may be seen as early as May or June, but is normally seen in August or early September. Early migrants are known to breed and individuals seen later in the year will therefore be a combination of the offspring from these migrants, as well as new immigrants from the continent. In good years, this species may produce up to 3 generations. It would appear that this species is unable to survive the British winter, although individuals seen in 1948 are believed to have survived a mild winter.
This fast-flying butterfly is probably overlooked given its similarity to the more-common Clouded Yellow, especially the pale helice form of the female Clouded Yellow. Even more challenging is the distinction with the equally-scarce Berger's Clouded Yellow. Even experienced Lepidopterists are unable to tell these two species apart, unless they have been reared from larvae, when the difference between the two species is obvious.
Description to be completed.
Eggs are laid singly on leaves of the foodplant. They are extremely pale when first laid, but gradually turn deep orange, and purple before hatching. Eggs hatch after around 10 days.
"The eggs are deposited singly, standing erect, with the base terminating in a thick patch of glutinous substance firmly adhering to the leaf. The egg is 1.1 mm. high, its greatest diameter is about one-third its height; in form it is elongate-ovate, attenuated at both ends, which are rounded; just below the summit it is very slightly concave; there are from nineteen to twenty-two longitudinal keels, mostly running the entire length, but some originating at different intervals from near the summit to about one-third down; the spaces between the keels have a flattened surface, and are most delicately but irregularly crossed transversely by about forty-six ribs. Its colour when first laid is a pearly-yellowish-white, which gradually deepens in hue, and when three days old its summit is transparent, white and glassy, shading into yellow for one-fifth down the side, where it deepens into clear rosy-orange, which colour prevails over the whole median area, occupying three-fifths of the entire length; the basal fifth is pale, similar to the crown, but not so transparent; the colouring thus remains unchanged until about thirty hours before hatching, when it gradually becomes deeper, and finally turns to a purplish-leaden colour, rather opaque; the shell has a very glittering silvery appearance and is exceedingly delicate. On August 18th, 1900, twenty C. hyale were captured at Sheerness, Kent, only two being females; one was apparently quite freshly emerged, the other being rather worn was placed on a growing plant of clover (Trifolium repens) the following day, when she deposited about forty eggs. She continued depositing for one week, during which time she was placed upon five different plants of clover. The number of eggs laid upon the separate plants were 40, 80, 60, 42 and 14 respectively — total 236, which is probably not the full complement of eggs for this species as C. edusa is capable of depositing about 500. The eggs commenced hatching August 29th, the egg state lasting ten days. The author has observed examples of this insect depositing eggs as late as September 20th." - Frohawk (1924)
In favourable conditions, larvae can feed up rapidly. Those that do not produce the next generation enter hibernation, curled up in dry leaves, and also change colour from a light green to a dull olive, reverted back to light green after hibernation. However, it would appear that the larva is unable to survive the winter in the British Isles. The larva has 6 instars in total and this stage lasts about a month for any summer brood.
The primary larval foodplants are clovers (Trifolium spp.) and Lucerne (Medicago sativa ssp. sativa).
"The larva makes its exit by eating a hole in the shell at the side near the crown. Its first meal after emerging is generally, if not always, the empty egg-shell, as the author noticed several larva feeding on them, and saw one larva, after resting in the usual manner along the midrib of the leaflet, turn round and crawl straight to its cast shell, and seizing one of the keels begin gnawing it through; it appeared to cut it through with difficulty, working its jaws like scissors, until at last it bit it asunder and then ate downwards; after making a short meal of this it returned to the midrib and again rested. This was a recently hatched larva, which had not been feeding on the leaf. Directly after emergence the larva measures 1.6 mm. in length, the body appears to be perfectly cylindrical; the head is large, globular, black and has a granulated surface and beset with numerous club-shaped, white, glassy tubercles. The segments of the body have five transverse wrinkles, or sub-divisions, which terminate just above the spiracles. The tubercles or processes sprinkled over the body are mushroom-shaped on the dorsal surface, where they form two sub-dorsal rows, two on each segment, the first one on the anterior wrinkle, the second, which is rather lower down, is placed on the fourth wrinkle or sub-division, another of similar shape is situated on the second wrinkle above the spiracle. Two other more elongated and club-shaped processes are situated by the spiracle, one behind and the other below it; on the base of the claspers are two simple white bristles; the spiracles are finely outlined with black, but somewhat indistinct and rather projecting. The whole surface of the body is very finely granulated, each granule being extremely minute and black; the ground colour is pale ochreous-yellow, but the granulations are so densely sprinkled over the surface that the larva exhibits a dull olive hue. The tubercles are shortest and stoutest on the head and along the sub-dorsal surface of the body, excepting those on the first and last segments, where they are longest and finest, especially the last pair on the anal segment, which are hair-like. The legs are whitish; the claspers are the same colour as the body. When quite young it feeds on the upper cuticle of the leaf, close to the midrib, and after each meal it returns to the midrib, along which it rests in a straight position, with its head furthermost from the spot where it feeds. It is very sluggish in its movements. When a few days old it eats through the leaf, completely perforating it. At ten days old and before moulting it measures 3.2 mm. in length, and is then of a pale ochreous colour, tinged with green and rather shining. The first one fixed itself for moulting on September 15th by spinning a layer of silk along the midrib, and thereon remained until it moulted for the first time on September 21st." - Frohawk (1924)
"After the first moult the colour is olive-green, with sub-dorsal longitudinal lines of pale whitish-green, these are principally composed of a series of warts, which also run in oblique short lines along the side; there is also a whitish lateral line and a number of tiny pale warts which are sprinkled over the body and head, all emitting rather short blackish hairs, those on the first segment being the longest and curved forwards; the head is olive-green mottled with dark olive-brown. Its first meal after moulting consists of a portion of the cast skin. On September 25th, when seventeen days old, it measures while resting 4.8 mm. in length, the colour is then of a greyish or smoky-green, with a rather dark medio-dorsal stripe, and an indistinct, pale, sub-dorsal line as previously mentioned, chiefly composed of pale warts. The body is smoother than before and the hairs are black. It feeds generally by beginning at the end of the leaflet." - Frohawk (1924)
"The second moult took place on October 3rd. On October 13th, after the second moult and thirty-five days old, it measures 6.35 mm. long; the body is almost cylindrical, being slightly dilated along the lateral line and rather attenuating to the anal extremity; the second and third segments are stoutest; the colour is a deep green, similar to that of a clover leaf, the segments clearly defined, and have each five or six transverse wrinkles, each wrinkle bearing a number of pale shining warts, with a black centre, and each emitting a moderately long black bristle. The warts are placed in longitudinal rows down the dorsal surface; there is a pale yellowish-white super-spiracular stripe; the spiracles are black and situated along the lower edge of the stripe. The head is pale ochreous-green, and like the body is studded with black-centred warts and black hairs curving forwards; the legs are dusky and the claspers green; the anal flap has a central blackish blotch. It rests in a straight position, but upon any disturbance it elevates the anterior half of its body, and remains in a curved attitude for a few minutes, and then attains its former posture. It feeds principally by day, preferring the sunshine. On October 18th the larvae entered into hibernation, having remained quietly resting upon a layer of silk spun down the centre of the leaflet. When placed in the sun on the 23rd at a temperature of 73 degrees Fahr., two became somewhat restless after about an hour, and slowly moved on to the adjoining leaflets. After moving sluggishly about, and without feeding, both returned to their respective resting places and took up precisely their former positions. Another larva fed a little during the midday sun, but afterwards all remained perfectly quiet, although they had been under similar conditions of temperature. The larva of C. hyale generally hibernates after the third moult, but sometimes after the second. Unlike C. edusa, C. hyale has a hibernating stage. The larva enter into hibernation about a month or five weeks after emerging from the egg, and remain in a state of complete torpidity throughout a period of about four months. From observations carried out it appears that the normal time for the larva to cease hibernation is about the middle of January. The larva are unable to withstand a temperature below about 40 degrees Fahr., and apparently continuous damp atmosphere is fatal to them, consequently they invariably succumb in this country." - Frohawk (1924)
"After the third moult, when hibernating and 108 days old, it measures 8 mm. in length; colour uniformly green, the spiracular line whitish-green, dilated and divided into four lobes of unequal sizes; on the second one, which is the largest, is placed the large, conspicuous, shining black spiracle; on the adjoining posterior lobe is a primrose-yellow oblique blotch; each segment is transversely and deeply wrinkled, the centre one so much so that it gives each segment a double appearance. The entire surface is densely sprinkled with black shining warts, of various sizes, some extremely minute, each one emitting a black shining bristle; these are straight on the dorsal surface, and rather curved on the lateral region, all being directed in various positions. The head, legs and claspers are similar to the body, all being covered with bristles and of a green colour. The body is also extremely finely granulated with the minutest black specks, principally on the dorsal area; these, together with the black bristles, give the larva a dark green colour and a rough appearance. From this stage the large black spiracles become less conspicuous. After hibernation and after third moult — over 160 days old — it measures 12.7 mm. long; the whole colouring is clearer and lighter than during hibernation; the head ochreous-olive and the spiracular line pale lemon-yellow." - Frohawk (1924)
"About a week after the fourth moult - 220 days old — it measures 19 mm. long; the general colouring and form are almost exactly similar to the previous stage, excepting the spiracular line is rather whiter, and in some specimens the yellow markings on the line are faintly shown; the spiracles in most cases are less black, having whitish centres, and the head is generally ochreous tinged with green, but some have almost clear green heads." - Frohawk (1924)
"After fifth and last moult, fully grown, about 240 days old, it measures 31.8 mm. long, and is almost cylindrical, but slightly largest at the third segment and tapering at the anal segments. The ground colour is a clear light green, but has a darkish velvety appearance, due to the entire surface being densely sprinkled with black warts, each emitting a moderately long black bristle. The bristles are black all over the dorsal surface and white on the ventral surface, each wart is encircled with whitish-green, and the intervening spaces have excessively minute black granulations; the spiracular line is tricoloured, having a white upper border running the whole length, the anterior half on each segment is a beautiful rich lemon-yellow, reaching just beyond the spiracle, then deepening into orange-vermilion, which fades into orange posteriorly; the spiracle is white, very finely outlined with black. The head, claspers and legs are green, and covered with bristles similar to the body. There is considerable variation in the colouring of the spiracular line; in some specimens the orange-vermilion is replaced by deep gamboge-yellow, and a remarkable variation occurs in some specimens by having a conspicuous black spot immediately below the spiracular line, precisely similar to Edusa; in some these spots occur from the third to the eleventh segments inclusive, in others it is only on a few of the segments, while others have no trace whatever of them; but usually, when they do occur, they are not so large as in Edusa. The similarity between the larvae of the two species is remarkable, and the only apparent differences are the following: In Hyale the black spots below the line are usually fewer and smaller, or altogether absent; the red of the spiracular line extends further across the segments, usually over the posterior half of each segment, and the bristles are somewhat darker and longer than those of Edusa. Finally the larva of Hyale lacks the fine whitish pubescence exhibited by Edusa. Also both the egg and the young larva of Hyale greatly resemble those of Edusa; the chief differences are — Egg: The spaces between the keels are flat in Hyale and concave in Edusa. The transverse ribs, which number about forty-six in Hyale, are in Edusa about thirty-six, and the colour is paler in Hyale, especially at the ends. Larva in first stage: Anal segment: first sub-dorsal pair of tubercles shorter and set rather wider apart in Hyale than those of Edusa. The dark colouring above is smoky and suffused in Hyale, which in Edusa is sharply defined, angular and black; the general ground colour of Hyale is greener and darker than that of Edusa. The main difference, however, between the two species is more apparent after the first moult, when the larva of Hyale is covered with short blackish hair, Edusa in the same stage being clothed with fine whitish pubescence." - Frohawk (1924)
The pupa is attached to a plant stem or leaf by a silk girdle and the cremaster. This stage lasts around 2 weeks.
"The pupa: The length varies from 20.5 mm. to 22.2 mm. and 6.3 mm. in greatest diameter; the head terminates in a short straight beak, the thorax is humped dorsally, the abdomen rounded and tapering to the anal point; wings ample, rounded, and swollen in the middle, reaching the division between the fifth and sixth abdominal segments; base of wings angular; dorsal half of head dark green, ventral half light green, the two shades being divided by a light greenish-yellow stripe, which extends along the inner sub-margin of the wing and spiracular line, enclosing the inconspicuous whitish spiracles. The whole of the dorsal surface varies from pale green to light greenish-yellow, in some specimens it is decidedly yellow; there is a medio-dorsal longitudinal line rather darker than the ground colour. The wings are of a duller and darker green, as are the legs and antenna. The ventral surface of the abdomen is of the same yellow-green as the dorsal surface. The inner margin of the wing is dusky-green, which borders on the sub-marginal yellow line. There is a sub-spiracular series of three minute black dots on the abdomen, and below these a lateral dark purplish-brown band composed of four oblong markings, one on each segment from the wings downwards, the last being very pale and small. On the wing is a sub-hind-marginal series of six black dots, each situated between the nervures and a central black discoidal dot. The pupa is suspended by a silken cincture round the waist and the attachment of the cremastral hooks to a silken pad spun upon the stem of the plant. The resemblance between the pupa of Hyale and Edusa is almost identical, the only differences which appear to be constant are, that the beak of Hyale is straight, which in Edusa is slightly upturned, and the apex of the wing in the latter does not reach so far down the abdomen as in Hyale. The first larva pupated on April 20th, which produced a male imago on May 7th, 1901, the pupal state lasting seventeen days." - Frohawk (1924)
The following links provide additional information on this butterfly.
