Masters of Darkness

Bay Bugs with Dr Isabella Brey

photo 1 – Cream-spot Tiger (Arctia villica)

The family Erebidae (from ‘Erebus’ – the god of darkness in ancient Greek mythology) is the largest and one of the most diverse moth families in the world. Almost 90 species of erebid moths are found in Britain, among which are some of the most striking and unmistakable native species.

photo 2 – Garden Tiger (Arctia caja)

Few other moths (or butterflies for that matter) are more colourful and memorable than a large tiger moth in full defensive display, when it reveals its almost luminous hind wings from beneath its vividly patterned forewings. One of the most beautiful of the British tiger moths is the Cream-spot Tiger (Arctia villica) (photo 1), which can reach a wingspan of up to 66 mm. While the Cream-spot Tiger is restricted to southern Britain, the slightly larger Garden Tiger (Arctia caja) (photo 2), is found through-out most of the country. Tiger moth caterpillars are quite distinctive too, and are often referred to as ‘woolly bears’ because of their thick covering of long, bristly hair, the density and appearance of which varies between species.

photo 3 – Cream-spot Tiger larva / photo 4 – Garden Tiger larva

photo 5 – Cinnabar Moth (Tyria jacobaeae) / photo 6 – Cinnabar larvae feeding

While caterpillars of the Cream-spot Tiger (photo 3), for example, possess neat tufts of short to medium length ginger hair on a dark background, those of the Garden Tiger (photo 4) sport particularly luxurious, long and thick hair. The hair protects the caterpillars from predators, both by forming a physical barrier against attack by small predators and parasitoids, as well as by causing itching and irritation in larger enemies.

On the other hand, the caterpillars of the closely related Cinnabar (Tyria jacobaeae) (photo 5) – one of the few species which flies on sunny days as well as during the night – are almost bald. Instead of relying on mechanical protection, Cinnabar caterpillars use chemical defences acquired from their toxic food plant. They advertise their distastefulness by means of highly conspicuous warning colours, further enhancing the effect by feeding in groups, often high up on ragwort stems (photo 6).

photo 7 – Pale Tussock (Calliteara pubibunda), larva / photo 8 – Pale Tussock larva curled up in defence

photo 9 – Pale Tussock, adult

photo 10 – Vapourer (Orgyia antiqua), larva / photo 11 – Vapourer, mating pair / photo 12 – Vapourer female laying eggs

Perhaps the most spectacular of all erebid moth caterpillars are those of the tussock moths. Tussock moths are named after the exception-ally thick tufts of defensive hairs (thought to be somewhat reminiscent of grass tussocks) which are a distinctive feature of their caterpillars. Although magnificent in their larval stage, tussock moths are usually well camouflaged as adults. One of the most frequently encountered tussock moth caterpillars is that of the Pale Tussock (Calliteara pudibunda) (photo 7), which develops on a variety of shrubs and trees – often in urban areas – where it usually goes unnoticed until it sets off in search of a suitable place to pupate away from its foodplant. If it is disturbed on its travels, it curls up into a tight ball, protecting its vulnerable underside while spreading its defensive hairs (photo 8). The adult Pale Tussock (photo 9), on the other hand, retains none of its juvenile defences, and is instead covered in thick, silky ‘fur’, particularly on its forelegs.

 

 

 

 

A tussock moth with some very unusual habits is the Vapourer (Orgyia antiqua). The attractive vapourer caterpillars (photo 10) are easily recognizable and behave much like those of other tussock moths. Male Vapourers (photo 11) are somewhat unusual in that they regularly fly during the day, often zig-zagging high in the air and rarely settling. Their motivation are the extraordinary, wingless, furry females of the species (visible to the left of the male in photo 11, and pictured egg-laying in photo 12). Female Vapourers produce a powerful pheromone that allows them to attract males from several kilometres away. Once mating has taken place, they glue up to 300 eggs onto the elaborate cocoon inside which they spent their pupal period. Not long after their work is done, the females pass away. Their distinctive hard-shelled eggs overwinter, and the new generation of caterpillars hatches in spring. Rather than hatching all at once, individuals emerge over a period of several weeks. As a result, adult Vapourers can be found any time from July to October.

photo 13 – Herald (Scoliopteryx libatrix) / photo 14 – Herald, larva

 

The Herald (Scoliopteryx libatrix) (photo 13) can be seen over an even longer period. This elegant species overwinters as an adult, and as such is often one of the last moths to be seen in the autumn, as well as one of the first to reappear in spring. Late in the year when most flowers have gone, it can often be found feeding on overripe blackberries during the night. Its well camouflaged green caterpillars (photo 14) develop on poplar and willow.

While the Herald is easily recognized by its distinctive outline, the unusually named Mother Shipton (Euclidia mi) (photo 15), is equally unmistakable on account of its distinctive pattern, which is thought to resemble the profile of the 16th century witch of that name. The Mother Shipton can be found quite easily because, unlike the majority of its relatives, it flies only in the daytime, usually in open, grassy areas where it can easily be mis-taken for a small butterfly. Approaching it can be difficult, however, because it spooks easily and is prone to flying off at speed when disturbed.

photo 15 – Mother Shipton (Euclidia mi)

With one species or other active at any time of the day or night, in virtually all habitats and throughout most of the year, erebid moths are a very accommodating family to study. This pursuit is made particularly rewarding by the family’s numerous brightly coloured and attractively patterned members, many of which are easily recognizable both in their larval and adult forms, and which are a pleasure to observe for children and adults alike.

 

 

 

 

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