Laothoe Populi

The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It is found throughout the Palearctic region and the Near East and is one of the most common members of the family in the region. It is distinctive due to its habit of resting with its hindwings held further forward than (but still half hidden by) the forewings.

Poplar hawk-moth
in Oxfordshire, England
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Sphingidae
Genus:	Laothoe
Species:	L. populi
Binomial name
Laothoe populi (Linnaeus, 1758)
Synonyms
List Sphinx populi Linnaeus, 1758 Sphinx tremulae Borkhausen, 1793 Merinthus palustris Holle, 1865 Smerinthus borkhauseni Bartel, 1900 Smerinthus roseotincta Reuter, 1893 Amorpha populi angustata (Closs, 1916) Amorpha populi depupillatus (Silbernagel, 1943) Amorpha populi flavomaculata Mezger, 1928 Amorpha populi lappona Rangnow, 1935 Amorpha populi pallida Tutt, 1902 Amorpha populi philiponi Huard, 1928 Amorpha populi suffusa Tutt, 1902 Laothoe populi albida Cockayne, 1953 Laothoe populi basilutescens Cockayne, 1953 Laothoe populi bicolor (Lempke, 1959) Laothoe populi minor (Vilarrubia, 1973) Laothoe populi moesta Cockayne, 1953 Laothoe populi pallida Newnham, 1900 Merinthus populi salicis Holle, 1865 Smerinthus populi cinerea-diluta Gillmer, 1904 Smerinthus populi decorata Schultz, 1903 Smerinthus populi ferruginea-fasciata Gillmer, 1904 Smerinthus populi ferruginea Gillmer, 1904 Smerinthus populi fuchsi Bartel, 1900 Smerinthus populi grisea-diluta Gillmer, 1904 Smerinthus populi grisea Gillmer, 1904 Smerinthus populi pallida-fasciata Gillmer, 1904 Smerinthus populi rectilineata Klemensiewicz, 1912 Smerinthus populi rufa-diluta Gillmer, 1904 Smerinthus populi rufa Gillmer, 1904 Smerinthus populi rufescens (de Selys-Longschamps, 1857) Smerinthus populi rufescens Fuchs, 1889 Smerinthus populi subflava Gillmer, 1904 Smerinthus populi violacea Newnham, 1900

Adults may be seen from May to September, and do not feed, not having a functional proboscis, and can vary in colour from grey to yellow. The larva is green, feeds on poplar and some other tree species, and pupates below ground.

Laothoe populi is a large (wingspan 70–100 mm (2.8–3.9 in)), odd-looking species of moth, due to its habit of resting with its hindwings held further forward than (but still half hidden by) the forewings. The species lacks a frenulum joining the wings together, and is said to look like a cluster of dead leaves of the main host, poplar.

When disturbed, the moth will suddenly reveal a bright orange-red basal patch on the hindwing, possibly as a distraction or startle display. The wings are grey marked with darker grey fascia but with the greys occasionally replaced by buffish tones, a form more frequent among females than males. There is a white spot at the distal edge of the cell on the forewings.

Gynandromorphs, half female and half male, are common.

Poplar hawk-moths have been known to produce a hybrid when mated with the eyed hawkmoth, Smerinthus ocellatus; the hybrid has eyes on the hindwings.

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  A male poplar hawk-moth, viewed from the back
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  A male poplar hawk-moth, viewed from the front
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  A female poplar hawk-moth, viewed from the back
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  A female poplar hawk-moth, viewed from the front
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  A gynandromorph poplar hawk-moth, viewed from the back
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  A gynandromorph poplar hawk-moth, viewed from the front

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  Mating pair showing both colour variants
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  Egg
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  late instar larva
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  Larva
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  Showing hindwing held forward of forewing
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  imago, showing orange-red basal patch on hindwing
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  imago, lateral view

One or two broods are produced each year and adults can be seen from May to September. The adults do not feed. The species overwinters as a pupa.

Egg

The egg is large, spherical, pale green, and glossy, and is laid singly or in pairs on the underside of leaves of the host plant. Females lay up to 200 eggs.

Larva

On first hatching the larva (or "hornworm") is pale green with small yellow tubercules and a cream-coloured tail horn. Later, it develops yellow diagonal stripes on its sides, and pink spiracles. Individuals feeding on willows may become quite heavily spotted with red. Others are more bluish white with cream stripes and tubercules. They are stout bodied, and grow to 65–85 mm (2.6–3.3 in).

Pupa

The larva pupates in an earthen cell 2–3 cm (0.79–1.18 in) below the surface, near its host plant. It has a short cremaster.

Adult

Although they emerge late at night or early in the morning, the moth flies starting from the second night and is strongly attracted to light. Having no functional proboscis, it does not feed.

Laothoe populi feeds mainly on poplar and aspen, but sometimes on willow, alder, apple, tomato, birch, elm, oak and ash. The food source used by the moth often depends on location.

• Laothoe populi populi
• Laothoe populi lappona (Rangnow, 1935)