The goldwing moth

Goldwing (Synthymia fixa)

The goldwing is a very common moth seen mainly in April and May. Like most other moths it is a nocturnal insect. It spends the day resting on vegetation. If disturbed it flies for a short distance and lands on another piece of vegetation trying to blend again with its surroundings.

When it is resting in vegetation it is not easily seen. It has a pair of orange under-wings, which it keeps hidden under the forewings but when it is disturbed and flies off these become suddenly visible startling any would be predator.

It lays its eggs on the pitch trefoil, a leguminous plant known in Maltese as silla tal-mogħoz hence its Maltese name baħrija tas-silla tal-mogħoz.

Most species of moths are nocturnal, but there are crepuscular and diurnal species. The hummingbird hawk moth can often be seen during the day inserting its proboscis into a flower while hovering in front of it.  

Although butterflies and moths are in many ways similar it is relatively easy to distinguish one from the other. The most obvious difference are the antennae. Butterflies have thin filamentous antennae, which are clubbed at the end whilst moths have comb-like or feathery antennae and if filamentous they are always unclubbed.

In most cases moth caterpillars spin a cocoon made of silk within which they turn into pupae. The butterfly pupae are usually exposed, although the skipper butterflies make crude cocoons in which they pupate.

Another important difference is the wing colouration. Butterflies are usually very colourful whilst moths are usually plain brown, grey, white or black patterned in such a way so as to aid camouflage whilst they are resting during the day.

Most butterfly and moths can also be told apart by the shape of their bodies. Moths tend to have stout hariy bodies whilst butterflies have slender and smoother abdomens. As a rule moths usually rest with their wings spread out to their sides whilst butterflies hold their wings vertically above their body unless they are basking in which case they hold their wings flat on the side to absorb the heat of the sun like solar water heaters. 

This article was published in The Times on 01.04.09.