Australian moth headed south

Last week, I was sent from Christchurch a photograph of the grass-eating caterpillar of a recently introduced Australian moth. This is the blood-spotted noctuid moth Proteuxoa sanguinipuncta (Guenee, 1852), family Noctuidae, which is native to Australia.

The caterpillar is striped brown, black and off-white (or cream). Its head and thorax are both narrower than the abdomen and darker in colour. A distinctive feature used in its identification is the white diagonal stripe on the side of the seventh abdominal segment. The fully grown caterpillar grows to about 4cm long. These caterpillars feed solely on grass and are a minor pest of pastures.

The adult moth has a wingspan of about 4cm and is distinctively marked, when live and not faded. The opulent brown forewings are crossed by three thin white wavy lines, bordered by rows of black, v-shaped marks. Each forewing bears two black spots ringed with red. There are also smaller, scattered, red dots and flecks. This bright coloration soon disappears after death. The hind wings are a tawny grey.

The male moth has dense fluffy scales like bushy hair on the tibia of the fore legs, this feature being very distinctive — there is nothing like it on other moths with which it might be confused. These hair-like scales eventually fall off dead male specimens, including those in institutional collections.

In Australia, the blood-spotted noctuid moth occurs in Queensland, New South Wales, Victoria, Tasmania, South Australia, and south Western Australia. It was first found in New Zealand in Hawke’s Bay in 2007 and is now found throughout most of the North Island.

By 2017, it had spread to the upper South Island and in 2021, it reached North Canterbury.

In February this year, Hugh Wilson reported numbers of adults seen for the first time in Hinewai Reserve on Banks Peninsula.

Very quickly moving south, the blood-spotted noctuid moth will soon reach Otago and become firmly established.

 

Anthony Harris