The Striped Hawk-Moth: A Fascinating Migrant of the Skies
The striped hawk-moth Hyles livornica is a captivating member of the Sphingidae family, known for its swift flight, striking appearance, and remarkable migratory behaviour. This blog post explores its global range, migration patterns, preferred conditions, food plants, occurrence in Britain, and identification features, drawing on scientific literature to provide a comprehensive overview.
Global Range
The striped hawk-moth boasts an extensive global distribution, primarily residing in warmer regions of the Old World. Its range spans southern Europe, Africa, the Middle East, and parts of Asia, including India and Central Asia. It is a common resident in Mediterranean countries and North Africa, where it breeds in warm, open habitats such as coastal areas, gardens, and woodland rides. In colder regions, such as northern Europe, it appears as a migrant, unable to establish permanent populations due to harsh winters. Occasionally, vagrants have been reported in far-flung locations, including Iceland and the Canary Islands, showcasing its impressive dispersal capabilities (Pittaway, 1993).
Migration Patterns
The striped hawk-moth is a renowned long-distance migrant, with movements driven by seasonal and environmental factors. Migration typically begins in spring, as early as February, with moths moving northward from breeding grounds in southern Europe and North Africa. Multiple waves of migration occur during settled periods of fine weather, particularly along the south coasts of Europe. These migrations can result in significant influxes in northern regions, including Britain, where the species is not a resident.
Unlike some migratory species with predictable return journeys, the striped hawk-moth’s migration is often described as an “irruption,” where individuals disperse widely without necessarily returning to their origin (Pittaway, 1993). The moths cannot survive cold northern winters, so populations in places like Britain rely on new arrivals each year. In exceptional years, offspring from early migrants may produce a second generation locally, but these larvae rarely survive winter conditions.
Migration Conditions
Successful migration depends on favorable weather conditions. Warm, stable weather with light winds facilitates the striped hawk-moth’s northward flights. Southerly winds, in particular, aid their dispersal from Mediterranean and African breeding grounds to northern Europe (Waring et al., 2009). High temperatures also enhance flight activity, as hawk-moths maintain thoracic temperatures above 45°C during flight, among the highest recorded for insects (Heinrich, 1971). These physiological adaptations allow them to undertake long journeys, often covering hundreds of kilometers in a single season.
Food Plants
The striped hawk-moth is polyphagous, meaning its larvae feed on a wide variety of plants. In the British Isles, caterpillars are commonly found on bedstraws Galium spp., such as lady’s bedstraw Galium verum and hedge bedstraw Galium album, as well as dock Rumex spp.. Across its global range, larvae consume a broader array of herbaceous plants, including rosebay willowherb Chamerion angustifolium, fuchsias, snapdragons, buckwheat, and sorrels. In hotter climates, large larval populations may feed on flower heads and seed heads, occasionally causing minor agricultural damage (Pittaway, 1993).
Adult moths, equipped with a long proboscis, feed on nectar from flowers with deep corollas, such as red valerian Centranthus ruber and petunias. Their feeding behaviour, often at dusk or early dawn, makes them important pollinators in their habitats.
Occurrence in Britain
In Britain, the striped hawk-moth is a scarce immigrant, appearing in small numbers most years, predominantly in southern England, southwest England, and southern Ireland. It is classified as a migrant species in surveys of British macro moths, with records peaking during strong migration years. For example, significant influxes were noted in 2000, 2003, and 2006, when moths were observed across parks and gardens (Waring et al., 2009).
Adults are typically seen between May and October, attracted to light traps or nectar-rich flowers. Caterpillars, the offspring of earlier arrivals, are occasionally found in June–July and September–October, feeding on low-growing plants like bedstraw and dock.
Identification
The striped hawk-moth is a striking insect, both as an adult and a caterpillar, making it relatively easy to identify.
Adult Moth: Adults have a wingspan of 6–8 cm. The forewings are greyish-brown with distinctive white veins and a prominent white stripe running from the base to the apex. The hindwings are pink with black bands, though these are often hidden at rest. The abdomen features black and white chequered markings, and the body is robust, typical of hawk-moths. Their rapid, agile flight and ability to hover while feeding resemble that of hummingbirds, a hallmark of the Sphingidae family (Heinrich, 1971).
Caterpillar: Larvae grow up to 85 mm and are highly variable in colour, ranging from green to brown or black. They feature a characteristic horn at the tail end, which is black with a yellow tip in mature larvae. The body is adorned with white and yellow markings, often in chevron patterns, and a pale stripe runs along the sides. In Britain, they are most often found on bedstraws or dock.
Similar Species: The striped hawk-moth can be confused with the silver-striped hawk-moth Hippotion celerio, a rarer migrant to Britain. However, H. celerio has a more silvery appearance and lacks the bold white stripe on the forewings (Pittaway, 1993).
Striped hawkmoth in a hotel in Menorca, an individual which was part of a good influx of this species on the island during June, likely from North Africa.
References
Pittaway, A.R. (1993). Hawkmoths of the Western Palearctic. This comprehensive guide details the biology, distribution, and migration of Hyles livornica and related species, serving as a foundational text for lepidopterists.
Waring, P., Townsend, M., & Lewington, R. (2009). Field Guide to the Moths of Great Britain and Ireland. This field guide provides detailed descriptions and distribution maps for British moths, including migrant species like the striped hawk-moth.
Heinrich, B. (1971). “Temperature regulation in the sphinx moth, Manduca sexta.” Journal of Experimental Biology, 54(1), 141–158. This study explores the physiological adaptations of hawk-moths, shedding light on their high-energy flight and migration capabilities.
Porter, J. (1997). The Colour Identification Guide to Caterpillars of the British Isles. A valuable resource for identifying hawk-moth larvae, including H. livornica, with detailed illustrations.
Porter, J. (1997). The Colour Identification Guide to Caterpillars of the British Isles.
