Butterfly or Moth?

When I was a child I thought the differences between butterflies and moths were simple – butterflies flew during the day and settled with their wings closed while moths were nocturnal, attracted to light and rested with wings displayed. Then I discovered that some moths are diurnal. Apparently the antennae give the most obvious clues to the nature of the beastie – usually. Butterflies have long thickened antennae which are club or pin-shaped at the ends. Moths' antennae are comb-like or feathery. There are exceptions – some moths have clubbed antennae and some butterflies from central African forests don't.

The Large or Cabbage White (Pieris brassicae) is an exception in the bright world of butterflies.

Most butterflies have brightly-coloured wings - wing colour and pattern play a major role in courtship. Night-flying or crepuscular moths usually have plain colours – black, brown, grey or white. Females attract males by releasing a chemical signal. Additionally their wings may have swirling or linear patterns which serve as camouflage when they are resting during the day. Exceptions are the day-flying moths which have bright colours, especially if they are poisonous. Moths have a frenulum – a minute hook or bristle – linking fore and hind wings. Butterflies lack this feature – usually. There is an Australian Skipper which has this.

The bodies of butterflies are slim while moths have sturdier often hairy bodies. Moths tend to look quite downy because the scales on their wings are larger, perhaps because they need to conserve heat in the cool of the night. Butterfly scales are smaller and they can utilise solar radiation.

Resting butterflies usually fold their wings though they bask with open wings for short periods. However, the skippers often resemble moths in their resting position while moths may fold their wings when in confined spaces.

The Dingy Skipper (Eryynis tages) looks quite like a moth with its thick body and habit of resting with wings outspread.