DISTRIBUTION:

Opodiphthera helena (wingspan 14-17 cm), the Helena Gum Moth, flies in Tasmania up to Central Queensland. It is reported from southern Queensland to Victoria, Tasmania, and from South Australia and south-western Western Australia.

Opodiphthera helena male, Tasmania, Beechford, North East Coast,
20. Dec. 1979, CSIRO

FLIGHT TIMES AND PREFERRED FOOD PLANTS:

Helena fly from October-November until January-February, apparently as a single brood.

Larvae feed on a number of Eucalyptus species: E. viminalis, E. obliqua and E. ovata.

Opodiphthera helena female, New South Wales, Armidale, 1. Feb. 1956, CSIRO

ECLOSION, SCENTING AND MATING:

Males and females feature different colouration. Females are usually less rusty red and more brown, with more prominent eyespots.

Photo (female) courtesy of Miguel de Salas.

Opodiphthera helena female, courtesy of Bart Coppens.

Emergence takes place during the early afternoon, when the eclosing adult softens the cocoon shell with a secretion of cocoonase, and cuts a circular hole with a hard hook at the base of the wing. Wings are fully dry the same evening, and females call about two to four hours after sunset.

Pairing is quite brief (half an hour to 1.5 hours) and difficult to witness. Some females lay most of their eggs that same evening. This male displays a posture which has been documented as typical of O. helena: squeezed abdomen, holding tight to whatever surface it is on, and rhythmically raising and lowering the forewings to expose the ocelli on the hindwings.

EGGS, LARVAE, COCOONS AND PUPAE:

Females deposit 150-200 large (3 mm x 2 mm) creamy-yellow eggs with a red-brown gum. Incubation is two to three weeks.

Larvae are predominantly black in the first instar with large "warts" and yellow-orange spots. The first instar last approximately seven days. Images and information on this page are courtesy of Miguel de Salas.

Growth is rapid and second instar larvae are mostly green, with red warts and a little black. By third instar all the black is gone. The red scoli with blue bases remain, and a light band appears, running the length of the body on both sides, just above the prolegs.

Curiously after every moult larvae almost always eat the exuvium, except the old head capsule. This newly moulted third instar larva will shortly turn and consume the discarded skin.

Fourth instar larvae are a darker shade of green, which camouflages them very well amongst non-glaucous Eucalyptus leaves. They have a pink/white band running all along the side, just above the prolegs, and the remaining scoli, on the thorax and the 11th segment, are now blue.

Tracheal openings are red, and the whole body is covered in short, creamy-white primary setae. The 5th instar, reaching 8 cm in length, is very similar to the 4th, just larger.The first four instars last approximately seven days each, but the 5th instar can last up to three weeks.

Opodiphthera helena, parasitized fifth instar, Shearwater, Tasmania,
March 5, 2010, courtesy of Kristi Ellingsen

Opodiphthera helena fifth instar, courtesy of Jim Tuttle.

Cocoons are spun wrapped among several leaves, the male and female differing in size quite obviously. Moths eclose in three weeks during continuous brooding or may stay in diapause for as long as two years.

Larval Food Plants

It is hoped that this alphabetical listing followed by the common name of the foodplant will prove useful. The list is not exhaustive. Experimenting with closely related foodplants is worthwhile.

Betula Eucalyptus baxteri..... E. obliqua E. odorata E. ovata E. viminalis

Birch Gum Messmate Gum Gum Manna gum

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