SATURNIA SPINI ([Denis & Schiffermüller], 1775) -- Sloe Emperor Moth

Phalaena (Bombyx) spini [Denis & Schiffermüller], 1775, Ankündung syst. Werkes Schmett. Wienergegend: 49.

Type locality: Vienna area, Austria.


Part of a plate from Kirby (1907).

BIOGEOGRAPHICAL AFFILIATION

Holarctic; western Palaearctic region. Pleistocene refuge: Monocentric -- Pontomediterranean refuge.


ADULT DESCRIPTION AND VARIATION

Wingspan 55--100mm, with females being the larger. Both sexes resemble grey females of Saturnia pavonia, i.e. the adults are not sexually dichromatic.


Female Saturnia spini, Bulgaria (Sandanski) x Macedonia (Veles). Photo: © Hynek Habal. Male Saturnia spini, Bulgaria (Sandanski) x Macedonia (Veles). Photo: © Hynek Habal. Male Saturnia spini, Saratov/Volgograd area, southern Russia. Photo: © A. Zagorinsky.

ADULT BIOLOGY

Unlike Saturnia pavonia, both sexes of this species are nocternal. It favours sunny, dry, bush-strewn steppe or semi-steppe, but can be found up to 1500m altitude in Turkey. A nomadic species whose colonies may shift from year to year. A member of the Pannonic steppe fauna which penetrates central Europe.


Typical habitat of Saturnia spini, Saratov/Volgograd area, southern Russia. Photo: © A. Zagorinsky. Typical habitat of Saturnia spini, Saratov/Volgograd area, southern Russia. Photo: © A. Zagorinsky.

FLIGHT-TIME

Depending on latitude and altitude, April to June as a single generation.


EARLY STAGES

OVUM: Oval, 1.4 x 2.2mm, greyish-white with olive-brown gum. Laid in neat clusters around peripheral twigs of the host, hatching ten to fourteen days later.

LARVA: Full-fed 65--80mm. Monomorphic.

As in Saturnia pavonia, the newly-hatched, 2.5--3mm-long larvae consume part of their eggshells before clustering together. At this stage they are black and bristly. Unlike Saturnia pavonia, the larvae do not change colour as they grow and remain black, but with some fine grey and blue markings. The button-like tubercles become reddish-orange.

The larvae are gregarious right up until the final instar, and can be conspicuous on their shrubby hosts.


Fourth instar larva of Saturnia spini, Saratov/Volgograd area, southern Russia. Photo: © A. Zagorinsky. Full-grown larva of Saturnia spini, Volgograd area, Russia, 10.VI.2007. Photo: © V. Schelokov.

Hostplants. In Europe, polyphagous on Prunus (P. spinosa), wild roses (Rosa), hawthorns (Crataegus), elms (Ulmus), alders (Alnus), willows (Salix), poplars (Populus) and apples (Malus); however, in Turkey and the Crimea it shows a distinct preference for spiny members of the rose family (Rosaceae). Between Saratov and Volgograd (Russia) it is generally found on species of Rhamnus (Oleg Gorbunov, pers. comm. 2005).

PUPA: 26mm. Dark brown to black, noticeably dorso-ventrally flattened, and 'comma'-shaped. Formed in a coarse, thin-walled, pear-shaped, double, unsealed brown cocoon low down amongst the hostplant, often at ground-level. The overwintering stage. Very tolerant of dry conditions, and may remain as a pupa for several years.


PARASITOIDS

Tachinidae: Blepharipa pratensis, Exorista grandis (Zetterstedt), Exorista sorbillans (Wiedemann), Masicera pavoniae (Robineau-Desvoidy), Masicera silvatica (Fallén), Winthemia quadripustulata (Fabricius).


DISTRIBUTION

From eastern Austria and Poland across eastern and southeastern Europe to Greece, Turkey, Armenia (Zolotuhin, Didmanidze & Petrov, 2011), the Ukraine, Crimea and Kazakhstan. There is an old report of this species from the Altai Mountains, but this requires confirmation.

Extra-limital range. None.


OTHER SUBSPECIES

None, although the population from the Ukraine and southern Russia -- haversoni Watson, 1911 -- is sometimes accorded subspecific status. There is, however, some confusion as to the type locality of this race, which may be eastern Turkey (see Nässig, 1981).



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