Moths and butterflies - the difference



So, what's a moth?  By which most people mean: how are they different from butterflies?


Not all moths are small. OK, the bus is a Dinky-type toy but the Great Atlas is still VERY big


There are thousands of articles online about the difference between butterflies and moths and I hesitate to add to their number. But I am persistently asked the question and so here is my reply which is based on a belief that non-specialists prefer to keep things simple.

Butterflies fly by day; moths by night

Butterflies have larger wings and float and flutter like gliders; moths are streamlined, purposeful and zoom and jink like jets

Butterflies have larger areas of clear, bright colour; moths appear dun and dull and their colours (a marvellous spectrum including shiny gold, silver and brass) are subtle and hard to see in flight

Butterflies have slender bodies; moths' bodies are dumpy and fat

Butterfly antennae are simple with a club at the tip; moths' antennae come in a fantastic variety of shapes

Butterflies have fewer than 60 different species in the UK; moths have over 3,500.

Butterflies fold their wings vertically above their bodies at rest; moths fold them horizontally over their backs.

Butterflies pupate in a hard, shiny chrysalis; moths use a furry cocoon.

There are exceptions to all these rules, to which the simple-minded such as myself reply triumphantly: "Indeed! And it is the exception that proves the rule."

Armed with these slightly flawed but essentially correct comparisons, the reader seeking further truth may then befriend a scientific colleague. They will learn fascinating further details which relate to the general differences described above.

For example, the different methods of flight are in part due to the fact that most moths but (so far as I am aware) no butterflies have a linking muscle called a Frenulum which hooks their forewings to their rearwings - ie one frenulum on each side of their bodies - and this enables them to harness all four wings in a rapid and co-ordinated manner.

Or, while all insects have compound eyes, most moths have Superposition eyes which improve night vision, while butterflies have Apposition eyes which are better suited to a life spent mostly in daylight.

If you pass on any of this priceless knowledge during conversation, you may well be challenged by another enthusiast. Have no fear! Even the greatest experts are divided on the subject and especially on those species which appear to disobey the rules. The scientific community often discusses exactly where butterflies and moths should be placed in the international classification of animal species.

However, I failed physics-with-chemistry O Level and never even took biology, so I will not go on about these things.






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