UKMoths 
63.038 BF1405
Mother of Pearl Pleuroptya ruralis
(Scopoli, 1763)
Wingspan 26-40 mm.
One of the largest of Britain's so-called 'micro-moths'; in fact it is larger than many of the 'macro-moths', though this division is largely artificial.
The moth rests with all four wings on display, which show a colourful rainbow-like lustre in certain lighting conditions, as the English name suggests.
Common throughout most of Britain, the adults fly from dusk onwards, and are often attracted to light.
The larvae feed on nettle (Urtica dioica), in a rolled-up leaf.
- Larva: (description Ian F. Smith):
Foodplant: September to June, but larva overwinters in cocoon on ground until March or April. Usually on Urtica, but also Chenopodium,Atriplex, Filipendula ulmaria or Humulus. Leaf folded, usually downwards, in March to early May. At first, resembles a leaf turned down by Anthophila fabriciana, but less silk used. Leaf rolled late May and June. Leaf sown into a pouch for pupation in June.
Early instar
Length: Description for 7mm and 11 mm larvae.
Head: Capsule brown, frons greenish brown, mouthparts reddish brown, stemmata black.
Prothorax (T1): Prothoracic shield dark brown divided by wide transparent medial strip showing green of viscera. Dark brown bisetose prespiracular pinaculum and subventral pinaculum.
Mesothorax (T2): One pair dorsal, and one subdorsal, bisetose pinacula. Two lateral pinacula, the anterior bisetose and posterior unisetose. One subventral unisetose pinaculum. All pinacula grey-brown.
Metathorax (T3): As T2. Thoracic legs: Base coloured as body. Femur, tibia and tarsus transparent tinted light brown. Upper surface of tarsus, and claw, marked brown.
Body: Transparent apple green, showing darker green of viscera medially. Segments T1-3, A1-4 paler than A5-10.
Spiracles: Peritreme small, brown. Transparency of body reveals white of internal tracheae under well lit magnification.
Abdominal pinacula: Large and grey-brown. Segments A1- A7 each have two pairs dorsal, one subdorsal and one subventral unisetose pinacula; one subventral bisetose pinaculum, and one basal trisetose pinaculum. Segments lacking legs or prolegs have a pair of ventral unisetose pinacula. On A8 the posterior pair of dorsal pinacula are fused into one. A9 has one large bisetose dorsal pinaculum.
Setae: Transparent colourless.
Anal segment (A10): Anal plate dark brown.
Prolegs: Base coloured as body. Planta elongated, thin, transparent colourless. Crochets reddish brown. Anal prolegs thicker, with some dark brown marks on base.Intermediate instar
Length: Description for 20 mm and 22 mm larvae.
Head: Capsule translucent clouded white tinted greenish brown. Mouthparts and stemmatal area blackish.
Prothorax (T1): Prothoracic shield transparent showing green of body below. Laterally one to three grey-black dots. Thinly edged grey-black postero-laterally.
Mesothorax (T2): One pair dorsal, one subdorsal, two lateral and one subventral pinacula. Pinacula slightly darker than integument.
Metathorax (T3): As T2.
Thoracic legs: Base green as integument. Femur transparent tinted green. Tibia and tarsus transparent tinted light brown. Claw reddish brown.
Body: Translucent milky green with viscera showing as darker green medial line.
Spiracles: White with light brown peritreme.
Abdominal pinacula: Concolorous with integument, or slightly darker, shiny and raised.
Setae: Translucent light brown.
Anal plate: Milky green as abdomen, but with lines of transparent dots that show the dark green viscera.
Prolegs: Base concolorous with body. Planta thin elongated, transparent whitish except green basally. Crochets light brown; arranged in double circle, incomplete on outer perimeter.Late instar
Length: Description for 25 mm larva.
Head: Frons and anterior of capsule transparent, showing apple green of interior. Capsule dorsally milky translucent with pale brown marks. Mouthparts reddish brown. A strong black band runs along the side of the capsule, through the stemmata and across the front of the capsule and mouthparts. In some specimens the band is blackish brown.
Prothoracic shield: Medially transparent colourless showing body and head below. Broad black band laterally.
Thoracic legs: Translucent, coloured as body, but tinted light brown. Claw reddish brown.
Body: Translucent milky green with viscera showing as darker green medial line.
Spiracles: Whitish tinted light brown.
Pinacula: Poorly sclerotised, concolorous with and discernable from the integument only by their raised form, lack of milkiness and greater transparency.
Setae: Translucent tinted light brown.
Anal plate: Milky green as abdomen, but with transparent dots that show the dark green viscera. Dots arranged in two transverse curved rows, the anterior with a curved branch at each end. Dots on posterior arranged in three pointed star.
Prolegs: Base concolorous with body. Planta thin elongated, transparent green fading distally to whitish. Crochets light brown; arranged in double circle, incomplete on outer perimeter.
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