Scarce Swallowtails' Violet Tinted Vista of Butterfly Bushes, English Lavender, and Lilacs

Iphiclides podalirius is commonly known in English as scarce swallowtail or sail swallowtail or pear-tree swallowtail.

The common name of scarce swallowtail derives from the scarcity of this swallowtail's appearance in the British Isles, where it apparently makes stray pilgrimages or inquisitive explorations yet does not establish new colonies.

Another common name, sail swallowtail, describes the butterfly's graceful flight pattern of rapid wing flutterings followed by extended gliding. Taking advantage of upward air currents as well as its own propulsion, Iphiclides podalirius sails majestically and effortlessly across the sky.

As they float across the sky, with their triangular forewings resting in a straight line from tip to tip, scarce swallowtails resemble large, zebra-striped kites with streamers flowing from behind, unattached and free in blissful escapes from earth's gravitational pull.

An alternative common name, pear-tree swallowtail, recognizes the proclivity of the caterpillar and butterfly stages of Iphiclides podalirius for cultivated and wild species of pear trees. In particular, caterpillars frequently may be found on the common pear tree (Pyrus communis). Less often, although not rare, are their appearances on wild apple, or crab-apple, trees (Pyrus malus). Scarce swallowtail butterflies also extract nectar from other species of pears, such as the ornamental Pyrus ussuriensis, commonly known as Chinese pear or Manchurian pear or Siberian pear, which produces heart-shaped leaves, masses of fragrant white flowers, and small, hard pears of decided unpalatability to humans.

This affinity for pear trees was acknowledged in the delicate drawing by English entomologist-illustrator John Curtis (September 3, 1791-October 6, 1862) that was incorporated in 1836 into the thirteenth volume of his sixteen-volume masterpiece, British Entomology, Being Illustrations and Descriptions of the Genera of Insects Found in Great Britain and Ireland.

Interestingly, scarce swallowtail caterpillars actually display the greatest preference for host plants in the Prunus genus, such as almond (Prunus amygdalus), European, or common, plum (Prunus domestica var. domestica), St. Lucie, or rock, cherry (Prunus mahaleb), sour cherry (Prunus cerasus), and sweet cherry (Prunus avium). In particular, scarce caterpillars are associated with blackthorns (Prunus spinosa), which inevitably are studded with eggs or crawling with larvae when their habitats overlap.

The original scientific name of Papilio podalirius was bestowed by the father of modern taxonomy, renowned and ennobled Swedish botanist-physician-zoologist Carl Linnaeus (May 23, 1707-January 10, 1778), in 1758. Sir Linnaeus' description was based upon a specimen collected in Livorno, Italy by esteemed English naturalist John Ray (November 29, 1627-January 17, 1705). The genus name, Papilio, is derived from the Latin word for butterfly, which also had determined the family name of Papilionidae.

Sir Linnaeus selected the species epithet, podalirius, to honor Podaleirios (Ποδαλείριος), a legendary healer in Greek mythology who was the son of Asclepios (Ασκληπιός), the god of medicine and healing.

In 1807, German entomologist-illustrator Jacob Hübner (June 20, 1761-September 13, 1826, Augsburg) devised another genus under the subfamily Papilioninae and named it Iphiclides in honor of Iphicles (Ιφικλής), half brother of Heracles (Ηρακλής), the strongest and one of the greatest heroes of ancient Greece.

The genus Iphiclides now consists of two to three species. In addition to podalirius, a sister species, Iphiclides podalirinus, commonly known as Chinese scarce swallowtail, is found only in China and southeastern Tibet.

Identified in 1832 by French entomologist Philogène Auguste Joseph Duponchel (1774-January 10, 1846) as a subspecies of the scarce swallowtail, Iphiclides podalirius ssp. feisthamelii restricts its homeland primarily to the Iberian Peninsula, the department of the Eastern Pyrenees (département des Pyrénées-Orientales) in southwestern France, and the North African countries of Algeria, Morocco, and Tunisia. Commonly known as Spanish swallowtail or Spanish scarce swallowtail, this butterfly is regarded by some entomologists and taxonomists as distinct enough from scarce swallowtails to be considered as a separate, and therefore third, species in the Iphiclides genus.

Distribution: an Old World native

Scarce swallowtails are an Old World butterfly in the family Papilionidae. They are considered natives of the Palearctic ecozone, which encompasses Europe, Asia north of the Himalayan foothills, and the northern and central Arabian Peninsula. Nevertheless, their natural distribution actually straddles the Indomalaya ecozone of south-southeast Asia with their nativity in Afghanistan, India, Pakisktan, and possibly Cambodia.

While occasionally sighted as far north as the British Isles and Sweden, scarce swallowtails are generally considered to be accidental strays or inquisitive explorers, not conscientious migrants, in those localities. In Belgium scarce swallowtails rarely visit the Flemish Region (Dutch: Vlaams Gewest), in the north, and are considered as a local but endangered species in the south.

While still considered as common with an indeterminate status of endangerment or threat, scarce swallowtails are protected by law in the Czech Republic, Germany, Hungary, Luxembourg, Poland, Russia, and Slovakia. Considered as rare in all of Austria's nine provinces, scarce swallowtails are protected in seven of them. Since 1993 scarce swallowtails, known in French as le Flambé ("flaming, flamed"), have been protected by law in l'Île-de-France (“isle of France”), the wealthiest and most populated administrative region, which is located in the northwest and includes Paris.

Habitat: a preference for blackthorn thickets and no fear of mountainous heights

Scarce swallowtails comfortably inhabit both lowlands and highlands. Drawn to gardens, meadows, orchards, steppes, and open woodlands, they especially favor blackthorn (Prunus spinosa), or sloe, thickets.

Evincing adaptability to a variety of elevations, scarce swallowtails are found at altitudes of 5,249 feet (1,600 meters) in the Alps. Their widespread distribution throughout Bulgaria also encompasses the highest mountain range, at 9,596 feet (2,925 meters), in Bulgaria as well as the Balkan Peninsul, Rila (Bulgarian: Рила), where they freely fly up to 5,577 feet (1,700 meters). Similarly, in Russia scarce swallowtails range from Moscow's plains in the northwest to the rugged peaks of the Altai Mountains in the southeast.

Life cycle: careful selection of birthing leaves

Eggs: Females oviposit, or lay, each egg singly on a carefully considered leaf. The decision to land on a potential plant is determined by sensory cues, such as visual or chemical. After landing, the final decision is based upon stimulants or deterrents detected by chemoreceptors which are located in the antennae, ovipositor (appendaged organ for laying eggs), proboscis (slender sipping tube), and tarsi, or feet (terminal segments of each leg).

Considerable time actually may be devoted to finding proper host plants because the fate of the egg and its larva, or caterpillar, depend on appropriate food sources. Oligophagous (Greek: ὀλίγος, oligos, “few” + φαγεῖν, phagein, “to eat”) in their diets, caterpillars mainly restrict their grazing to certain woody plants in the Rosaceae family, especially blackthorns (Prunus spinosa) and pear trees (Pyrus communis). Thus, the nourishment requirements of the larvae, the second stage of the life cycle, are considered in the fourth stage by the female scarce swallowtail as she makes decisions about the first stage.

Generally eggs are deposited onto the sunny areas of host plants.

Round in shape, eggs have cream yellow or pale green coloration.

Depending upon temperature, eggs hatch within one to four weeks.

Caterpillars: The first instars, or developmental stages, of the caterpillar primarily are occupied with spinning a silk cushion onto their birth leaf as a resting site. Considered to be highly territorial, Iphiclides podalirius caterpillars also spin thread trails which subsequent instars rely upon in their forages to guide them back to their birth leaves. Threads are imbued with a unique volatile marker which ensures recognition by each caterpillar and precludes confusion over resting sites.

Robustly stout in the thorax, caterpillars taper distinctly towards their tail end.

The first two instars are largely blackened. Green bodies, which are marked with a yellow line along the middle of their backs, appear with the third instar. Yellow stripes slant across the sides and are spotted with orange to red dots.

Sixteen feet extrude along the bottom of the body. Six emerge from the pectoral region while the abdomen has eight. There are two anal feet.

Typical of the swallowtail species, Iphiclides podalirius possesses an osmeterium (Greek: ὀσμή, osmē, “smell, odor”), a fleshy and forked retractable gland which emits malodorous compounds. Usually concealed behind the head, the osmeterium is everted, that is, turned outwards, and activated as a defense strategy when the caterpillar feels threatened or is alarmed.

Pupation lasso: In the third stage of its life cycle, the scarce swallowtail pupa affixes itself to a surface, such as a leaf or stem, at its tapered tail and lassoes itself around its thorax.

Blending with their surroundings, pupae in late spring are green while those in late autumn, which overwinter, are brown.

The number of generations produced within one year is determined by altitude and latitude. In central Europe and at higher altitudes, only one generation, flying from May to July, is evinced. In the Mediterranean region, scarce swallowtails are multivoltine as two or three generations usually are produced annually. The first flight of the metamorphosis from the overwintering pupae occurs as early as March. The second flight appears in July and August.

Emergence as a butterfly signifies the fourth, or flight, stage in the scarce swallowtail's life cycle.

The ultimate transformation: The winged insect which emerges from pupation bedazzles with its dramatic, distinctive outline and coloration.

A key identification feature of scarce swallowtail butterflies is their antennae, which end in clubheads, reminiscent of golf clubs.

A second key feature is their tails, which may reach 0.59 inches (15 millimeters) in length. Extending from the hindwings, black tails terminate in cream or yellow.

Hindwings are scalloped with cream to yellow or orchre crescents, which are overarched by blue lunules, or crescents, outlined in black.

On each hindwing, about midway between the tip of the abdomen and the tip of the tail, is a blue lunule outlined in black, topped with a burst of orange, and margined in yellow or ochre.

Uppersides of forewings and hindwings are white to cream or yellow to primrose. Black wedge-shaped stripes, which traverse the forewings, radiate outwards from the thorax in three paired sets. A final wedge angles dramatically near the black margin.

Wingspan ranges from 2.36 to 3.14 inches (60 to 80 millimeters).

Nectar sources: the attraction of violet-tinted flowers

In addition to tree flowers, scarce swallowtails are attracted to other flowering plants. Especially tints of floral violet entice and satisfy them. Four violet-tinted flowers which particularly guarantee endless nectarivorous fascination from scarce swallowtails are

*** butterfly bushes (Buddleia davidii),

*** English lavender (Lavandula angustifolia), and

*** lilacs (Syringa vulgaris).

Scarce swallowtails with butterfly bush

Buddleia davidii, or Buddleja davidii, is commonly known as butterfly bush or summer lilac.

An Old World plant, butterfly bushes have a native distribution from central China to Tibet. As one of the cold hardiest Buddleia, butterfly bush flourishes at high altitudes up to 7,800 feet (2,600 meters). The U.S. Department of Agriculture Plant Hardiness Zones Map, which classes plants according to the coldest temperature at which they remain viable, identifies butterfly bush as thriving from Zone 4 to Zone 9 (-30 to 30 °F; -34 to -1 °C).

Long popular as an ornamental since its introduction onto the world garden stage at the end of the nineteenth century, butterfly bush adapts easily to temperate areas as well as to such adversities as drought, intense heat, high humidity, and poor soil.

With so many spectacular cultivars continuously being bred from Buddleia davidii, it is universally familiar and is considered to be integral to attractive, fragrant gardens.

Particularly receptive to full sunlight, butterfly bush reaches a height of 10 to 17 feet (3 to 5 meters) and has a spread of 17 feet (5 meters).

Long, lance-shaped leaves, which are paired oppositely along branches, have medium green to grey green to dark green uppersides and woolly white undersides.

Opening profusely and fragrantly by mid-summer, butterfly bush flowers last until the first frost. Small, tubular florets, or tiny flowers, form cone-shaped clusters known as panicles (Latin: panicula, "tuft on plants"). With four spreading petals apiece, each floret petitely measures about 0.5 inches (1 centimeter) in length and 0.1 inches (3 millimeters) in width.

Floral colors range from white to golden yellow and from pink to light blue to lavender and from mauve to red purple. Violet or purple tints such as lavender and mauve especially cast a phenomenally irresistible spell upon scarce swallowtails, which, nevertheless, are completely devoted to any incarnation of butterfly bush.

Scarce swallowtails with English lavender

Lavandula angustifolia is commonly known as English lavender.

An Old World plant, English lavender is native to the Mediterranean region, where it naturally forms intensely fragrant heaths in the wild on rocky outcroppings along the sea famously described as "wine dark" in the circa eighth century B.C. Greek epic, Homer's Odyssey (Ὀδύσσεια, Odysseia).

With its gentle floral pastel and seductive, pleasant fragrance, English lavender has earned worldwide acclaim as a landscape enhancer. According to the U.S.D.A. Plant Hardiness Zones Map, English lavender thrives from Zone 5 through Zone 10 (-20 to 40 °F; -29 to 4 °C).

Exuberantly responding to full sun, English lavender reaches a height of 2 to 3 feet (0.6 to 0.9 meters) and spreads to a generous width of 4 feet (1.2 meters).

Narrow, grey leaves are softened with down.

Flowers open fragrantly in lavender spikes in early summer.

Scarce swallowtails with lilacs

Syringa vulgaris is known in English as lilac or common lilac or French lilac.

Of the almost two dozen species of Syringa, only two are native to Europe: Syringa josikaea, known as Hungarian lilac, and Syringa vulgaris. All the others are primarily native to northeast Asia.

Syringa vulgaris has graced gardens in western Europe since the sixteenth century.

This Old World favorite was transported in the early days of the American colonies as a vital component of herb gardens, which were grown for culinary, medicinal, and ornamental purposes. The enduring appeal of Syringa vulgaris is evinced in the development of over 1,500 cultivars from this amiable shrub.

According to the U.S.D.A. Plant Hardiness Zones Map, lilacs remain viable in Zones 4 through 9 (-30 to 30 °F; -34 to -1 °C).

Appreciating full sun, lilacs have an equiproportional shape with a height and a spread of 20 feet (6 meters).

Dark green leaves are paired on opposite sides of stout stems or branches. Cordate (Latin: cor, "heart") leaves point the tip of their heart shape outwards while the doubly curving top arches away from the petiole (Latin: petiolus, "little foot"), that is, the stalk which attaches the leaf blade to the stem.

In late spring to early summer showy flowers open fragrantly and profusely in cone-shaped panicles of blue, white, lavender, or deep purple.

Scarce swallowtails and favorite nectaries: a floral setting of violet-tinted resplendence

As scarce swallowtails flutter, glide, and swoop through gardens and countrysides, they target three preferential nectar sources which embellish the Old World's iconic architectural and pastoral landscapes with a spectrum of violet tints. All three nectar sources have garnered worldwide acclaim among humans for their unfailingly pleasant fragrances and impressive visual appeal. As such, scarce swallowtails do not have to conduct vain, extensive searches for these nectarous treasures. Moreover, they generously share these violet-tinted settings with other winged admirers. As a result, any and all observers who happen upon the scene are rewarded with a serene vista of stunning natural beauty, fragranced with familiar, enticing aromas and graced with the elegant flow of faunal and floral harmony.

My special thanks to Roger Gibbons for quickly and graciously granting permission to include his http://www.butterfliesoffrance.com/ photo of "Iphiclides podalirius egg on blackthorn leaf", taken on May 20, 2009, in this presentation.

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My special thanks to talented photographers/concerned organizations who make their fine images available on the internet.

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Copyright Thursday, September 22, 2011 by Derdriu