Friday, 21 September 2007
Hercules Moth: male top, female below.
Donuca rubropicta (Butler)
Hypsidia erythropsalis (Rothchild): Head-on view top, dorsal view below.
More on moths
One of the icons of the northeastern Australian rainforests is the Hercules Moth, Coscinocera hercules, one of the world’s largest moths. Females are larger than the males, often attaining more than 20 cm across and have shorter tails. Males are usually darker than the females. These moths seem to be most active on cooler nights. Adults do not feed. They, like many other moths, survive for a few days on fats stored during the caterpillar stage. Males are more commonly found at lights. If they are recognised in the morning, the Butcherbirds finish them off. Females lay about 200+ large eggs on a variety of trees, both native and introduced. Size of the adult moths varies, probably based on the quality of the food they have eaten.
The family Oecophoridae is probably the most diverse family of moths in Australia. The larvae seem to be leaf litter feeders and occur in regions outside of the rainforests. The most common families in the rainforests seem to be the Noctuidae and the Geometridae. The oecophorids are present but in numbers less than encountered elsewhere. Perhaps, that is because leaf litter is more promptly processed in the rainforests. In the eucalypt woodlands where oecophorids predominate, leaf litter is deep and not so quickly processed. Who knows? Donuca rubropicta (Butler) is a beautiful noctuid moth that frequently comes to lights. It seems to combine cryptic, disruptive and startle colour patterns.
Hypsidia moths have been bandied about from the Noctuidae to the Pyralidae but are now placed in the Drepanidae, the Hook—tip moths. H. erythropsalis Rothchild is a common visitor to lights in the Kuranda rainforest. But it really does not have hook-tipped wings! Maybe it is still misplaced in the Drepanidae. But as I have noted previously, though common, it is one of those moths that I have never encountered during the day. It must be distasteful as birds avoid eating the moths from the light sheet.
Thursday, 20 September 2007
One of the many colour phases of Syntherata janetta (White) (Saturniidae)
“Australia has somewhere between 20,000 and 30,000 species of moths (a number comparable to the number of flowering plants)….” A quote from the recent book by Zborowski & Edwards (2007). So it’s not too bold to suggest that there might be 1,000 species living in the rainforests and associated woodlands around Kuranda. In fact, there may be many more than that! I have been collecting moths for the Australian National Insect Collection, CSIRO, Canberra, every night for more than 4 years and not a night goes by that I don’t find one or more species that I had not seen before. They are so diverse in size, colour pattern, habitus and behaviour that one local artist has adopted them as an artform. His mothology site mothology is well worth a look. All the moths he uses in his art are from the Kuranda environs. Remarkable!
This is the first in a series of blogs on the moths of Kuranda.
The majority of moths are active at night. You see very few of them during the day. Most of the moths I find I have never seen in nature-only at the light sheet. Their diurnal activities, if any, are not known. It is assumed that most sit motionless to avoid predation. The wide range of colour patterns suggests a variety of strategies. Brightly coloured, often reddish or orange, moths are usually distasteful to birds and lizards. That this advertising strategy works is seen each morning on the light sheet. The moths are often the only ones that birds and lizards have left there.
The larvae (caterpillars) of most moths have not been seen. Some of the more prominent species Hawk and Silk Moths have large and obvious caterpillars and they are common if you find the appropriate host plants. But the great majority of caterpillars are hidden and have never been seen.
Some moths are seasonal, others can be found at most times of the year. And there are some that are vagrants. That is they are just flying through and are attracted by the light. The group of moths above illustrates what one might expect on a night in the rainy season. They are mostly noctuids feeding on fruit in the bird feeder. The largest moth is Ischyja neocherina, one of the fruit moths that causes damage in orchrds due ot its feeding activities which allow fungi to damage the developing fruit.
Zborowski, P., Edwards, E. D. 2007. A Guide To Australian Moths. CSIRO Publishing, Melbourne.