Deilephila elpenor, the elephant hawk moth or large elephant hawk moth, is a moth in the family Sphingidae. Its common name is derived from the caterpillar's resemblance to an elephant's trunk. It is most common in central Europe and is distributed throughout the Palearctic region. It has also been introduced in British Columbia, Canada. Its distinct olive and pink colouring makes it one of the most recognisable moths in its range. However, it is quite easy to confuse the elephant hawk moth with the small elephant hawk moth, a closely related species that also shares the characteristic colours. The moth is also known for its hovering capability, which it utilises when feeding on nectar from flowers.

Description

The D. elpenor moth has olive-brown coloured forewings outlined with pink. Two pink lines also run through the wings. The first line is usually thicker and terminates in the center of the wings near a white dot. The second line, which runs below the first, starts at the white inner margins and runs until the tip of the wing. The hindwings have a black inner half that gradually turns pink from the middle outwards. It is outlined by white fringes. The head, thorax, and body are also olive-brown in colour with pink markings throughout.

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Deilephila elpenor elpenor MHNT CUT 2010 0 229 Vernoux, Ain, France male dorsal.jpg|Male dorsal view

Deilephila elpenor elpenor MHNT CUT 2010 0 229 Vernoux, Ain, France male ventral.jpg|Male ventral view

Deilephila elpenor MHNT dos.jpg|Female dorsal view

Deilephila elpenor MHNT ventre.jpg|Female ventral view

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Subspecies

Two separate subspecies, Deilephila elpenor elpenor and Deilephila elpenor lewisii, were recognised in the past, but they are no longer regarded as well-distinguished. Similarly, the subspecies Deilephila elpenor szechuana is now thought to be a synonym for Deilephila elpenor elpenor. The subspecies Deilephila elpenor macromera, found in southern China, northern India, Bhutan and Myanmar, is still regarded as distinct.

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Deilephila elpenor macromera MHNT CUT 2010 0 229 China male dorsal.jpg|Male Deilephila elpenor macromera, dorsal view

Deilephila elpenor macromera MHNT CUT 2010 0 229 China male ventral.jpg|Male Deilephila elpenor macromera, ventral view

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Similar species

The elephant hawk moth is often confused with the small elephant hawk moth (Deilephila porcellus). There are clear distinctions in size and colouring that can help differentiate between the two. As the name suggests, the small elephant hawk moth is much smaller. It is also more yellow in colour around its body. The most obvious defining feature is the thick pink stripe going down the elephant hawk moth's abdomen that is missing on the small elephant hawk moth's abdomen. The two species are not usually seen together in garden traps because the small elephant hawk moth prefers more open habitats.

Range

D. elpenor is very common in central Europe and has a distribution throughout the palearctic region. The moths are also attracted to gardens, and eggs have frequently been found on garden fuchsias, dahlias, and lavender. The eggs are whitish-green and have a glossy texture.

Variation in colour has been observed in nature. Specifically, a green version of the full-grown larva exists within the species. Previous research has shown that the colour variation is not due to a simple inheritance pattern, and specific explanations still remain inconclusive.

Pupa

thumb|left|200px|Pupa

It takes around 27 days for D. elpenor to move from the larva stage to the pupa stage.

Adult

The wingspan of D. elpenor that have been collected in Europe measure to be around .

When it feels threatened by a predator, the caterpillar will widen the anterior part of the body. This defensive posture emphasises the eyespots and makes it more conspicuous. Some research have suggested that this allows the eyespots of the caterpillar to resemble a snake more closely than it could when it is at rest. Most vertebrates, such as humans, lose the ability to use the three types of photoreceptors present in the eye in dim light conditions. However, all three types of photoreceptors remain functional in various light conditions for D. elpenor, giving it the ability to have scotopic colour vision. This species was the first instance in which being able to see colour at night was documented in animals. However, despite the great sensitivity of its eyesight, the moth also has a reasonable spatial resolution. This nighttime colour vision is necessary because of the moth's feeding patterns. D. elpenor feeds at the darkest hours of night and also hovers over the flower to suck its nectar out rather than sitting on the flower. Locating the correct flower and hovering over it are both visually demanding tasks.

Visual cues

Since they are nocturnal, the moths tend to feed on flowers that open or produce nectar at twilight or during the night. These are commonly termed "hawkmoth flowers".

D. elpenor are particularly adept at hovering, which is a necessary skill for obtaining nectar. It utilises spatial cues and motion-detecting neurons to steady itself.

Predators

Some natural predators use bright colouring to attract its prey, which includes D. elpenor. The conspicuous body colouring of certain nocturnal invertebrates, such as the white forehead stripes on the brown huntsman spider, lures the flying moth to its predator.

Bats are also known to prey on the moth.

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File:Deilephila elpenor 3.jpg|Larva

File:Mittlerer-Weinschwärmer-Deilephila-elpenor.jpg|Green colour morph of the larva

File:Deilephila elpenor 03.jpg|Adult

File:Mittlerer Weinschwärmer Raupe Deilephila elpenor.jpg|Eye markings of the larva

File:Chenille de Deilephila elpenor 02.jpg|Eye markings on the larva

File:Mittlerer-Weinschwärme.webm|Video of the larva

File:Deilephila elpenor pupa.jpg|Pupa

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References

  • "69.016 BF1991 Elephant Hawk-moth Deilephila elpenor (Linnaeus, 1758)". UKMoths.
  • More images, UK Virtual Field Guide
  • Description in Richard South's The Moths of the British Isles
  • Lepiforum e.V.