HYLES NERVOSA (Rothschild & Jordan, 1903)

GB: Ladakh Hawkmoth

Celerio euphorbiae nervosa Rothschild & Jordan, 1903, Novit. zool. 9 (Suppl.): 721.

Type locality: Sabathu, [Kashmir,] north-west India.


BIOGEOGRAPHICAL AFFILIATION

Holarctic; western Palaearctic region. Pleistocene refuge: Monocentric -- northern section of Sindian refuge.


ADULT DESCRIPTION AND VARIATION

Male Hyles nervosa, Safed Koh Mountains, Afghanistan.

Wingspan: 68--87mm. In the male, the tegulae are fringed with white, the abdomen has only two black lateral spots and the fringes of the tergites are not white along the dorsal ridge. Dorsally, the forewing veins are outlined with white in the post-discal area.


ADULT BIOLOGY

A local species, but which can occur in very large numbers in a given area. In Kashmir, generally occurring at 2500--3000m (Bell & Scott, 1937) where stands of herbaceous Euphorbia are common.


FLIGHT-TIME

Apparently trivoltine; March to May, June/July and September.


EARLY STAGES

OVUM: Almost spherical, pale green and very like that of Hyles euphorbiae (Linnaeus, 1758). Laid in small clusters of up to twenty on the young shoots of the hostplant.

LARVA: Full-fed, 80mm.


Larva of Hyles nervosa. Image: © Tony Pittaway.

In the first instar the 4mm-long larva is off-white with a black horn and head. The coloration of the final instar, which is primarily black with small white to pale yellow spots, begins to show in the second instar. A dorso-lateral line of single, white eye-spots, one per segment, runs from the white-speckled head to the jet black horn. The shield, anal claspers and prolegs are black and an unbroken dorsal line of the same colour stretches from head to horn. There is also a noticeable ventro-lateral line of medium-sized yellow spots. This colour scheme is constant, with little or no variation, unlike that of Hyles euphorbiae.

According to Bell & Scott (1937), the larvae are gregarious and, having stripped one plant of its leaves, move en masse to the next. They feed quite openly, although when nearly full grown they tend to rest along the stems of the hostplant close to the earth. If disturbed, they simultaneously regurgitate drops of green fluid. Such gregarious behaviour is probably a defence against tachinid parasitoids.

Occurs from April to October, most commonly from June to August.

Hostplants. Herbaceous Euphorbia spp.

PUPA: 45mm. Very similar to that of Hyles euphorbiae, but head, thorax and wings dull green. The overwintering stage.


PARASITOIDS

None recorded.


DISTRIBUTION

Eastern Afghanistan (Ebert, 1969) and northern Pakistan (Rafi et al., 2014).

Extra-limital range. Northern-western India and the extreme west of Xizang Province/Tibet, China.


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