Tuesday, 24 March 2009

A Couple of neat moths

A Couple of neat moths

Murdock de Baar recently published notes on the biology of two rainforest moths in the Australian Entomologist. Both moths occur in the Kuranda rainforest as noted below.
Bracca rotundata (Butler) appears at the light sheet nearly every night. It is a geometrid with a wingspan of around 50 mm but for some reason does not look much like a geometrid. It usually rests quietly and remains well after the lights go off in the morning. It must be distasteful to birds and lizards because the moths often remain on the sheet throughout the day even though honeyeaters and other small birds continually visit the smorgasbord of small insects. De Baar reports that the larva (caterpillar) of B. rotundata was found on the rainforest vine, Austrobaileya scandans and were brightly coloured black and white and brilliant orange. It would seem that they are aposematically coloured and distasteful to birds as the adults seem to be. Buck Richardson has used this moth in his Mobile moth Mandela #2.

Bracca rotundata

The Large Leaf Moth Oxycophina theorina has a different story. This moth is a member of the Thyrididae, a diverse family with some destructive species. O. theorina rarely comes to our lights. It is a little smaller than Bracca but much more robust. We would average no more than two per year. De Baar found them feeding on street plantings of Macarangia tanarius in Normanton, Qld., a locale far-removed from rainforest. M. tanarius is a rainforest primary understorey tree. The caterpillars feed inside the stems of the trees and cause damage.

Oxycophina theorina

de Baar, M. 2008. Life history notes on Bracca rotundata (Butler) (Lepidoptera: Geometridae) and Oxycophina theorina (Meyrick) (Lepidoptera: Thyrididae) Australian Entomologist, 35: 141-143.

1 comment:

Ian McMillan said...

These are both moths I would never see at these latitudes. Most of my geometrids must be edible: if I don't get up early a range of birds from kookaburras to peewees comes to visit the sheet on my verandah wall and they all disappear.

I have attracted a regular clientele of green tree frogs, velvet geckos, and small bats, who all find my UV light to be a very useful delicatessen.