Insects and their Allies  

Lepidoptera: moths and butterflies

This is one of the most well known and easily recognisable orders of insects and contains about 21 000 species in Australia. Moths and butterflies are grouped together in the order Lepidoptera, which means 'scaly wings'. Below are the main characteristics of butterflies and moths.

Junonia villida calybe
Junonia villida calybe
(meadow argus butterfly)

  • 2 pairs of membranous wings that are covered in tiny scales which overlap like shingles on a roof. A few moths are wingless
  • One ocelli present above each eye
  • Antennae present. Antennae are long and slender in female moths and generally feathery in male moths. Butterflies have clubbed antennae
  • Mouthparts are formed into a sucking tube known as a haustellum

The larvae are typically known as caterpillars and have a sclerotised head with chewing (mandibulate) mouthparts, 3 pairs of thoracic legs and often short, unsegmented prolegs on the abdomen.

Is it a moth or a butterfly? Put simply, butterflies are just day-flying moths. Butterflies have clubbed antennae and the habit of holding their wings vertically when at rest whereas moths sit with their wings flat. Some day-flying moths are brightly coloured and may be mistaken for butterflies.

Bogong moth
Meadow argus butterfly

Life Cycle
Moths and butterflies undergo a complete life cycle that includes four stages: egg, caterpillar (larvae), pupae and adult. The eggs are usually laid on or close to the caterpillar's food plant either singularly or in groups. A female may lay only a few eggs or tens of thousands depending on the species, but several hundred is reasonably typical. After hatching caterpillars usually develop through 4 to 7 instars over a period of a few weeks up to a few months depending on the species, before pupating. When ready to pupate caterpillars generally find a sheltered site to spin their cocoons. Some may pupate attached to vegetation, others in the soil or leaf litter or inside the wood they have been tunneling in. Many moths and butterflies have one or two generations each year while others may breed continuously. Other species such as the large wood-boring Cossidae may take up to five years to develop.

Most larvae of moths and butterflies are herbivores either eating foliage or wood, but some are carnivorous cannibalising other caterpillars or feeding on soft bodied insects such as scale or ant larvae. Adults are generally nectar feeders, although a few have reduced mouthparts and do not eat at all.

Moths and butterflies occur over most of Australia and the range of their food plants largely determines their distribution. As nearly all caterpillars feed on plant material you are likely to encounter them on all plant parts including flowers, seeds, leaves, fruit, bark, wood and roots. Adult butterflies can generally be seen flying close to their food plants during the day, moths are mostly nocturnal and may be attracted to lights at night or observed during the day resting camouflaged on tress trunks and other surfaces, in dark crevices or on their host plants.