SOUTH AUSTRALIAN MOTHS
|Moths can be as pretty and intriguing
as butterflies. Most moths have evolved to fly at night but there are also day
flying moths. The night moths tend to be drab coloured, especially their forewings,
usually having a cryptic pattern that blends in with green foliage or brown bark used by
the moths for camouflage protection when they are resting during the day. But quite often
their hindwings are brightly coloured which they can use as a sudden flash-display
mechanism when they are in a resting position, to startle predatory birds that are looking
for an easy meal. Day flying moths however, can be brightly coloured and just as beautiful
as butterflies. Often these bright colours in the larger moths signify they are
distasteful, and some moths like the day flying black and white/yellow Agaristid moths can
also have aposematic coloured black-red-orange-yellow marked bodies signifying their
distaste. When disturbed, such moths flagrantly expose their abdomens to predators
to warn them of their distaste. The smaller bright coloured day flying moths use their
colours to blend in with flowers. Some larger moths are tailed, such as the giant
male Australian Atlas Moth or Hercules Moth and the Brown Swallowtail Moth occurring in
the tropics. When settled, most moths rest with their forewings folded over their
hindwings in the shape of a pitched tent or roof, with their antennae folded out-of-sight
beneath their wings. Some moths like the Geometridae rest with flattened wings, but
very few rest with wings fully open.
A lot less is known about South Australian moths than butterflies, which is largely due to a lack of published information and images. But in recent years there has been a marked improvement in information in both books and on the Internet. About 10,000 moth species are known from Australia, and there are many moths still undescribed. More detailed information is still required on the biology and food hosts of South Australian moths, which can be published in the newsletter of Butterfly Conservation South Australia. For information on how you can further take an interest in moths and butterflies refer to Butterfly Conservation South Australia.
Moths comprise both the smallest and the largest of the Lepidoptera, from a few millimetres to as large as a dinner plate. Their ancient ancestors flew alongside dinosaurs. They can be solitary or they can occur in massive migratory swarms, the latter often unnoticed during the night. They are a large food source for night flying birds (owls) and animals (bats), and also our nocturnal, native marsupial animals. Most moths have coupled fore and hind wings, usually by a spine-like frenulum process on the hindwing that fits into a groove on the forewing underside, effectively forming a more efficient single wing. Some moths make a clicking noise when flying, and some can make a whistling sound. Some, like Hawk Moths, can hover like a humming bird or helicopter. Some moths (particularly the females) do not have wings or are rudimentary. Some have clear wings or large clear windows inserted into their wings (Hercules Moth), others have plume-wings like the feathered wings of birds. Others have large ocelli 'eyes' on their wings (Emperor and Granny or Old Lady Moths) that mimic the eyes of lizards, night birds or small animals.
Some moths, like Bardi, Rain, Wood and day flying Sun-moths, may not have a proboscis for feeding and live off stored fat accumulated during their larva-pupa stage. Those with a proboscis feed mostly on flower nectar, but some feed on ripe fruit (fruit piercing moths), plant sap, 'honey-dew' of sap-sucking insects, animal sweat and fresh excrement, and even animal blood (similar to vampires). Some moths can run quickly like a cockroach. Moths hear by picking up sound vibrations on specialised auditory hairs on their bodies, and some moths have specialised tympanal ears capable of picking up the ultrasound of flying bats and can thus evade these predators while in flight. The males often have comb-like or pinnate antennae that are capable of detecting female pheromones (scents) from very large distances up to about 20km! Some moths are mimics and resemble bees and wasps to escape predation, while some larger tropical moths mimic poisonous swallowtail butterflies. A few moths at rest mimic bird droppings.
Female moths usually lay their eggs carefully on or near their host, singly or in small to large batches, but some like the large Rain Moths are often capable of randomly laying vast numbers of tiny eggs. Moth eggs come in a variety shapes and can be smooth or ornamented. Some females are parthenogenetic, reproducing themselves without cross gamete fertilisation. Moth larvae (caterpillars) are usually herbivorous and are sometimes a pest of our crops, but sometimes they also feed on fungus or algae, or can be carnivorous (on other insect or moth early stages) or feed on animal matter, corpses and excrement (Clothes Moths). They can feed above ground on bark, foliage, flowers, seeds, or feed on the ground on leaf litter, or bore into stems, trunks and seed-pods, or even live underground on roots and tubers. Others can be found in our homes living on our carpets and clothes, and in the pantry. Some even live under-water feeding on aquatic plants, and are capable of extracting oxygen from the water via filament-like gills. Some larvae (particularly the witchetty grubs) can take several years to mature, and the larva-pupa stage of the Yucca Moth in North America can live for 30 years. Bright coloured larvae are usually distasteful to predators.
Different groups of moths usually have distinctive types of larvae or larval shelters. Larvae can be smooth or hairy, the latter can be sparse or dense (woolly bears) or consist of tufts. Some larvae can have a velvet appearance like the large Snout Moth larvae. The pest Noctuidae moths have the cutworm or armyworm larvae, while the Geometridae have the looper larvae. The Ghost, Goat, Rain, Swift, Wood, and day flying Sun Moths have large witchetty or bardi grub larvae. Cup Moth larvae are brightly coloured and slug-shaped having extendable stinging tentacles like a sea anemone, while its pupa shelter has a small cup or gumnut shape. Bag Moths live in large communal bag-like silk shelters in the foliage of the host plant. The Case Moths have larvae that live in long portable shelters formed from cut-off twigs or leaves. The large Hawk Moth larvae have a dorsal spine at their rear end, while Tiger and Anthelid Moths often have woolly-bear larvae. Some larvae like the Fruit Piercing and Hawk Moths can have large eye-spots. The very small moths can have the wriggling leaf-roller larvae, or leaf miners that 'mine' beneath leaf cuticle creating clear windows in leaves, or eat the new growth tips or tunnel into stems and green fruit (Codling and Fruit Moths).
Most moth larvae construct some form of a silken cocoon within which they pupate. Many moths pupate within soil. Those larvae that are already protected by bags, cases, cups, holes and tunnels etc, will still line their final resting place with silk.
Few moths are seen flying during the day in South Australia, but on suitable nights an outside light can attract many local moths. An ultraviolet light and the bright mercury vapour lights to be found on certain roads will attract even more numbers. Moth numbers and diversity increase significantly as one enters the realm of native vegetation habitat such as the Mt Lofty Ranges and country areas. Moths can fly during hot or cold weather, and even tolerate light rain.
CSIRO Moth Image Gallery [Good]
CSIRO Search for information on moth (or butterfly) [Good, if you know what you want]
More information and images are available via Google, Flickr, TrekNature, Webshots, Wikipedia etc but you need to know what you are specifically looking for when you do a search.
McQuillan PB and Forrest JA (1985) A guide to Common Moths of the Adelaide Region. Special Educational Bulletin Series (No. 5), 52pp. South Australian Museum, Adelaide. [A good quick reference to some South Australian moths, with colour and b/w images, although some scientific names are no longer correct]
Links last checked 18 May 2009
Author: R. GRUND, © copyright 16 May 2009, all rights reserved. Last update 23 May 2009.