49.137 BF964

Cochylis dubitana

(Hübner, [1799])

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Wingspan c. 13 mm.

This species has two generations, flying in June and again in August. It is distributed widely in the south of Britain, but becomes scarcer northwards. The drier substrates found on limestone and coastal sand, appear to favour it in North Wales and NW England.

It can be distinguished from two similar relatives by the following features:

                   Head & palps   Thorax
C. dubitana        white          blackish
C. atricapitana    blackish       blackish
C. hybridella      white          white

The larvae, in July and August-April, feed inside flowers and developing seedheads of various Compositae, including ragwort (Senecio), Hawkbeards (Crepis spp.), Hawkweeds (Hieracium spp.), Perennial sow-thistle (Sonchus arvensis) and goldenrod (Solidago virgaurea). There is usually no external sign of feeding, and occupancy rates are often low (e.g. 5 larvae from 133 opened seedheads of Sonchus arvensis). Larvae overwinter in a cocoon among debris from October to April.

See 'show detail' for larval descriptions.

Pupation in April-May, and in July, is in a cocoon on the ground among debris.

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Larva: (description Ian F. Smith)

Foodplants: In Flowers and developing seedheads of compositae, including Senecio spp., Crepis spp., Hieracium spp., Sonchus arvensis and Solidago.
In July, and in August to April.

Early instar
Length: 5 mm described (7 mm similar)
Head: Pitchy black. Mouthparts dark reddish brown.
Prothorax (T1): Dark brown prespiracular sclerite. Prothoracic shield pitchy brown.
Thoracic legs: Translucent blackish grey. Base as venter.
Body: Finely shagreened. Translucent. Greasy whitish, with slight tint of orange-yellow on dorsum. Orange viscera faintly visible in anterior of body.
Spiracles: Fine brown peritreme.
Pinacula: Small. Un-shagreened. Coloured as body.
Setae: Fine. Transparent colourless.
Anal plate: Translucent blackish grey.
Prolegs: Coloured as venter. Crochets reddish brown. Large lateral translucent blackish grey sclerite on anal proleg.

Intermediate instar
Length: 9 mm described
Head: Burnt ochre. Posterior edged pitchy brown. Frons edged brown. Mouthparts dark reddish brown. Stemmatal area black.
Prothoracic shield: Transparent shiny light brown, shaded darker in posterior and laterally. Divided by yellowish white medial line, which narrows to very fine at anterior. A transverse row of orange-brown dots at a third from posterior turns to follow the edge of the medial line.
Thoracic legs: Translucent light brown.
Body: Densely finely shagreened, except transparent intersegmentally showing dark viscera. Dorsally orange-yellow. Ventrally yellowish-white.
Spiracles: Fine orange-brown peritreme.
Pinacula: Small. Slightly paler than integument. Slightly glossy, un-shagreened.
Setae: Fine transparent colourless.
Anal plate: Transparent yellowish white. Finely spotted with brown.
Prolegs: Coloured as venter. Crochets reddish brown.

Late instar
Length: 12 mm described.
Head: Light brown. Some dark marks on posterior half. Posterior edged dark brown. Mouthparts dark reddish brown. Stemmatal area black.
Prothoracic shield: Translucent shiny. Shading from whitish anterior to dark brown posterior. Generally appears darker than head. Divided by yellowish medial line which is widest at posterior.
Thoracic legs: Translucent yellowish brown.
Body: Densely finely shagreened. Small transparent area intersegmentally showing dark viscera. Dorsally orange-yellow. Ventrally yellowish-white.
Spiracles: Small, unobtrusive. Very fine, almost imperceptible, brown peritreme.
Pinacula: Small, inconspicuous, coloured as integument.
Setae: Fine transparent colourless.
Anal plate: Small, brown with fine darker spots.
Prolegs: Coloured as venter. Crochets reddish brown.