Type species: Sphinx euphorbiae Linnaeus, 1758.
A cosmopolitan genus containing up to 29 species and 42 subspecies (Kitching & Cadiou, 2000), depending on how one classifies the populations and races. Hyles appears to have evolved in the Neotropics during the Oligocene/Eocene epochs. It is a very young genus that radiated on a global scale rather quickly (Hundsdoerfer et al., 2005b).
(Taxonomic notes. (i) Within the Hyles genus there is a complex of species, subspecies and forms, all closely related to Hyles euphorbiae (Hundsdoerfer et al., 2005b), and all of which are highly polymorphic with an amazing variety of colour forms, some geographic in nature, others environmental. The Hyles euphorbiae complex is rather difficult to classify for it would seem to be in the process of diverging into a number of species. Many of the following species and subspecies are regarded by some authors (e.g. Speidel & Hassler, 1989) simply as subspecies and forms, respectively, of Hyles euphorbiae. Electrophoresis has not yet been undertaken on this complex; it may solve some of the problems of relationship as it has for the Papilio (Pterourus) glaucus (Linnaeus) complex in North America (Hagen et al., 1991; Hagen & Scriber, 1989, 1991). Examination of the genitalia is of little use as they show practically no difference between taxa; however, mtDNA studies by Hundsdoerfer et al. (2005b) has started to unravel the inter- and intraspecific relationships.
Larval coloration and pattern do, however, provide a very good guide to the relationships between the many 'species' and 'subspecies'; this same conclusion was also reached by Shchetkin (1956) and Meerman (1993). By reference to these, in combination with other features, such as differences in female 'calling' times (Harbich, 1994), it is possible to group together certain species, subspecies and forms.
(A numerical taxonomic analysis (using phenograms) of this complex by Meerman (1993) broadly supports these groupings, as do the studies of Hundsdoerfer et al. (2005b).)
An intriguing explanation for the variability of Hyles euphorbiae s. str. has been put forward by Harbich (1976a). Primary hybrids between Hyles euphorbiae s. str. and other Hyles species were able to produce viable offspring when back-crossed with Hyles euphorbiae s. str., but not, however, with the other parent. Thus the variability of Hyles euphorbiae s. str. could be the result of a genetic influx from other members of the genus, such as Hyles hippophaes, Hyles vespertilio and Hyles gallii (see Harbich, 1976c), which themselves would be protected from the influence of Hyles euphorbiae. This view is supported to some extent by the findings of Hundsdoerfer et al. (2005b). Of course, the degree of influence the other species have on Hyles euphorbiae would depend on how often interspecific crosses occur, which, in turn, depends on how closely related the species are. Additionally, gene flow between Hyles tithymali and Hyles euphorbiae may be decreased by genetic linkage between ecologically important traits in sex chromosomes, such as an adaptation or lack of adaptation to desert conditions. These species appear to be primarily maintained by ecological selection reinforced by behavioural differences and not genetic barriers. (For more information see Harbich (1988, 1989, 1991, 1992, 1994).)
(ii) Hyles costata (Nordmann, 1851), found from the Altai through Mongolia to Amurland and northern China (Derzhavets, 1979a), is a valid species with a very distinct larva. It appears to be related to Hyles tithymali (Hundsdoerfer et al., 2005b). However, Meerman (1993) considers Hyles costata to be a subspecies of Hyles euphorbiae, although somewhat distant.)
IMAGO: Forewing entire with apex pointed. Forewing pattern very distinctive, consisting of a pale cream or white, oblique median stripe in most species. Antenna distally incrassate in both sexes and, in female, strongly clavate. Pilifer with long setae medially, short setae laterally. Eye lashed. Labial palpus smoothly scaled with no erect hairs, concealing base of proboscis; scaling at apex of first segment not arranged in a regular border on inner surface; second segment without apical tuft on inner side. Abdomen conically pointed, with strong dorsal spines usually arranged in three rows. External spines of foretarsus more or less prolonged, always longer than the respective spines on the inner side of tarsus; comb of mid- and hindtarsus vestigial, the spines not much prolonged. First segment of hindtarsus shorter than tibia. Inner distal spur of hindtibia more than twice as long as outer and about half tibial length. Pulvillus absent or vestigial.
Genitalia. Very simple and similar in all species, thus of little use in distinguishing species. In male, valva broadly sole-shaped; friction scales numerous and small in most species. Sacculus ending in a thin, more or less curved, simple, tapering process. Aedeagus with dorsal apical edge incrassate, dentate, produced at left side into a short process; length of brim-like incrassation, as well as dentation, slightly different in various species.
Behaviour. An interesting characteristic of all Hyles species is their reaction to disturbance. Dropping to the ground, the abdomen is hunched, the wings are swung upwards and the antennae laid forward until they touch. The insect then hops about in short jumps.
OVUM: Small, almost spherical, pale green or blue-green.
LARVA: Typically sphingiform; thorax slightly tapering anteriorly. Usually with a conspicuous dorso-lateral line of eye-spots. Many are polymorphic, the forms themselves varying in background colour, spots and the colour of these spots. Horn present or absent.
PUPA: Proboscis fused with body, not projecting anteriorly, not obviously carinate. Light tan, smooth, covered with short, fine dark lines. Cremaster large, sometimes bent ventrally, with an apical pair of spines. In a fairly substantial cocoon on the ground.
HOSTPLANT FAMILIES: Principally herbaceous plants of the Euphorbiaceae, Onagraceae, Rubiaceae, Zygophyllaceae, Elaeagnaceae and Liliaceae.
GB: Spurge Hawkmoth, F: Sphinx de l'Euphorbe, D: Wolfsmilchschwärmer, RU: Molochainyi Brazhnik, S: Vitsprötad Skymningssvämare, NL: Wolfsmelkpijlstaart, CZ: lisaj pryscový, H: kutyatejszender, E: esfinge de la lechetrezna
Sphinx euphorbiae Linnaeus, 1758, Syst. Nat. (Edn 10) 1: 492.Type locality: Unspecified [Europe].
(Taxonomic notes. (i) 'Subspecies' strasillai, rothschildi, subiacensis, dolomiticola and filapjewi are all forms which were incorrectly given subspecific status; they can be found intermittently throughout the range of Hyles euphorbiae euphorbiae. 'Subsp.' lucida does not warrant subspecific status as it falls within the normal variation of Hyles euphorbiae euphorbiae, both as a larva and adult.
(ii) Meerman (1993) disagrees with the inclusion of Hyles euphorbiae vandalusica within Hyles euphorbiae euphorbiae and gives it full subspecific status based on phenographic analysis. However, larval evidence from Portugal suggests that this taxon is a natural hybrid with Hyles tithymali gecki, similar to those found on Malta and Crete. (See below photo for details.))
Holarctic; western Palaearctic region. Pleistocene refuge: Polycentric -- Atlantomediterranean, Adriatomediterranean and Pontomediterranean subsections of the Mediterranean refuge, and the Caspian and Iranian refugia. Probably also several of the adjacent eremic refugia.
Wingspan: 70--85mm. Very similar to the other subspecies and to Hyles tithymali, Hyles centralasiae and Hyles nicaea. Normal specimens of each are illustrated in Pittaway (1993) but, due to the great wing-pattern variation exhibited by Hyles euphorbiae euphorbiae, some confusion may arise. Such variation includes wings with no trace of red; wings deeply flushed with red (f. grentzenbergi Staudinger); hindwings rust-brown (f. brunnescens Schultz), or yellow (f. lafitolei Thierry-Mieg) in place of the normal red. All other coloration can vary widely, while in the most extreme form the entire forewing is brown with a series of small, cream, dagger-like markings replacing the oblique median stripe (f. restricta Jordan).
Many Chinese individuals are more heavily spotted in a manner similar to Hyles nicaea sheljuzkoi Dublitzky, 1928 (Pittaway, pers. obs.).
Can be very common in warm, dry years but very scarce in cold, wet ones. Found where perennial herbaceous Euphorbia species are present, with open, sunny locations being preferred, such as along the edges of fields and woodland, on coastal sand-dunes and on mountain-sides up to 1900m in the Alps.
By day, most individuals rest on stones, low walls, amongst low vegetation, or even on the ground, taking flight just after dusk for a short period and again later, in three or four bouts of activity which, in the males at least, usually cease by midnight. It is during one of these that pairing takes place, usually four to five days after emergence and usually between 22.00 and 24.00 hours (Harbich, 1994), although Friedrich (1975, 1982, 1986) quotes 21.00 -- 23.00 hours. The pair remain in copula for up to three hours. Following separation, females begin oviposition almost immediately, laying a few eggs on the first night and more on subsequent nights. Although this species is attracted to flowers and feeds avidly from beds of, for example, Petunia, Oenothera, Echium, Epilobium, Nicotiana or Silene, few come to light.
Univoltine in its northern range, mainly from mid-June to the beginning of July, although individuals can be found as early as mid-May. Farther south, two generations are normal, one in May/June, the other in August/September. However, at higher altitudes in southern Europe there is only one generation during June and July (Ganev, 1984). In the southern Urals, from late May until early July, late July, with a partial second/third generation in late August--early September (Nupponen & Fibiger, 2002).
OVUM: Almost spherical (1.1 x 1.0mm), light glossy blue-green. Deposited either singly or in small clusters at the tip of a shoot of the hostplant, hatching about ten days later. Interestingly, the eggs of this species are extremely hard; if dropped on to a hard surface they will rebound to a considerable height.
LARVA: Full-fed, 70--80mm. Polymorphic.
The newly-hatched larva measures approximately 4mm and is off-white with a black head and horn. With feeding, this primary colour is soon replaced by dark olive black which then lightens with further feeding. At this stage it rests low down on the hostplant during the day, at dusk moving up the stem to feed during darkness in the company of others. After the first moult, the characteristic bright pattern appears, superimposed on a now light greenish yellow-brown background. With each successive moult this becomes more startling until, eventually, the fully-grown larva can feed quite openly, relying on its aposematic coloration for protection. Although the basic pattern remains the same, size and colour are just as variable in the larva as in the adult insect (see Buckler, 1887). The dorso-lateral line of eye-spots may be red, yellow, green, white or orange, set in a ground colour which varies from green through light yellowish brown to black.
At all stages, its feeding powers are prodigious. Vast quantities of leaves and also soft stems are consumed between spells of basking, which it does more frequently as it grows. If disturbed, a thick stream of dark green fluid is ejected from the mouth towards the attacker, accompanied by violent body twitching from side to side. Hundsdörfer, Tshibangu, Wetterauer & Wink (2005) have demonstrated that although this species does not sequester plant toxins in its body tissues, the green plant slurry present in the anterior gut is rich in phorbol esters, which are potent toxins and irritants. Protection by toxic gut contents (and not sequestered toxins) is also found in the larvae of Daphnis nerii.
Prior to pupation, the larva is very active and wanders a great distance at a very fast pace, finally pupating a considerable way from the hostplant.
The larvae are very sensitive to photoperiod and temperature, and will not go into diapause if exposed to long-day conditions of 17 hours light and 7 hours darkness and >18 degrees C (Harbich, 1976b).
Occurs in most areas throughout July and August; in June and August/September where two generations are present.
Major Hostplants. Herbaceous species of Euphorbia, especially E. paralias, E. cyparissias and, in southern Europe, E. characias.
Minor Hostplants. Very occasionally, Rumex, Polygonum, Vitis, Mercurialis and Epilobium. In Switzerland it is not infrequently found on Polygonum aviculare (Schweizerischer Bund für Naturschutz, 1997).
PUPA: 45--50mm. Light yellowish brown with fine, dark striations. Formed within a loosely spun, net-like cocoon, incorporating leaves, soil and other debris, on the surface of the soil. The time spent in this stage can vary considerably -- from two weeks to two years. Overwinters as pupa.
Braconidae: Cotesia nigriventris (Nees), Cotesia saltator (Thunberg); Tachinidae: Blepharipa pratensis (Meigen), Blondelia nigripes (Fallen), Drino galii (Brauer & Bergenstamm), Exorista larvarum (Linnaeus), Masicera sphingivora (Robineau-Desvoidy), Pales pavida (Meigen), Winthemia cruentata (Rondani).
From western Europe (Portugal (Corley, 2004)), and southern and central Europe to the Urals (Kumakov, 1977; Nupponen & Fibiger, 2002), southern western Siberia (Zolotarenko, Petrova & Shiryaev, 1978; Izerskiy, 1999), the western fringes of the Altai Mountains (Izerskiy, 1999) and western China (Xinjiang Province). Also, Turkey (Daniel, 1939; de Freina, 1979) Transcaucasia, northern Afghanistan (Ebert, 1969), Kyrgyzstan (S. Toropov, pers. comm.) and the western Tian Shan (Alpheraky, 1882; Derzhavets, 1980). Not found in Corsica, Sardinia or the Balearic Islands (Pittaway, 1983b). A migrant to the north.
It should be noted that some populations in Portugal and southwestern Spain appear to be hybrids of this species and Hyles tithymali gecki.
Extra-limital range. The eastern Tian Shan (Bang-Haas, 1936) and much of Xinjiang Province, China (Pittaway, pers. obs).
Also, introduced into many areas of the U.S.A. and Canada to control non-native pest species of Euphorbia (Hodges, 1971; Batra, 1983). It is particularly common in Montana, Alberta and Ontario.
Israel, Jordan, Lebanon, Syria, southern Turkey, northern Iraq and northwestern Iran as subsp. Hyles euphorbiae conspicua, with an isolated population in the south-western mountains of Saudi Arabia.
From Iran and the Kopet Dag Mountains of Turkmenistan eastward to central and eastern Afghanistan, ?Kashmir, the Pamirs and western Pakistan as subsp. Hyles euphorbiae robertsi.
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