There's no doubt moths and butterflies can look quite similar and it can be quite confusing trying to decide. Here Butterfly Conservation explains how they differ.
How to tell the difference between moths and butterflies
There are several useful rules of thumb you can start with that help you tell a butterfly from a moth:
- Butterflies usually have ‘club-shaped’ antennae, moths meanwhile normally have antennae that taper to a fine point and may or may not also be feathery. The two can have quite similar shaped antenna, however, take the dingy skipper butterfly and six-spot burnet moth, for example.
- Butterflies usually fold their wings vertically above their backs, while most moths hold their wings horizontally when resting.
- Moths also have a frenulum, a tiny bristle that hooks the front and hind wings together – no European butterflies have these.
Are butterflies more colourful than moths?
You can also ignore the common misconceptions about butterflies and moths. For example, many believe that moths are mostly duller colours of browns and greys and that butterflies are more colourful, however, you can get brown butterflies just as you can get moths of all colours of the rainbow.
Do moths just fly at night?
Also, while it is believed that moths only appear at night, there are plenty of species that fly in the daytime (a far higher number than there are of butterflies) and some butterfly species like the red admiral also fly at night when on migration.
Do moths and butterflies share the same diet and habitats?
Different species enjoy a range of different caterpillar foodplants. For example, the Essex skipper butterfly caterpillar enjoys cock’s-foot while the common blue mainly feeds on bird’s-foot-trefoil. Meanwhile, the December moth eats the leaves of broadleaved trees in comparison to the lace border moth that prefers thyme and marjoram.
Therefore, while butterflies and moths broadly enjoy the same habitats there are some differences. Many moths have caterpillars that live on broadleaf trees, whereas this is unusual among native butterflies, and there are far more moth species associated with wetlands than there are butterflies. Overall, both butterflies and moths require a rich and diverse ecosystem with a wide variety of native foodplants for their caterpillars to feed on.
The destruction and deterioration of habitats is the main cause of the dramatic declines that both butterflies and moths have undergone in the UK.
So how different are moths to butterflies?
However, the true answer is that there isn’t much difference at all. They both belong to the group of Lepidoptera, which is one of the most species-rich groups of animals in the world. There are over 165, 000 known Lepidoptera species across the globe, far more that all of the mammals, birds, fish, reptiles and amphibians put together. But only around 18, 000 Lepidoptera species are butterflies; in essence, butterflies are just one particular branch of the moth family tree.
Exactly where the butterfly part of the moth family tree fits is less clear. It is hard to unravel the inter-relationships between Lepidoptera families, mainly because there was extremely rapid diversification among these insects around 100 million years ago. Physical and, in particular, molecular characteristics of modern moths are enabling scientists to chart the evolutionary course of the Lepidoptera. One surprising revelation is that butterflies appear to be much more closely related to various micro-moth families than, as had long been thought, the macro-moths. Essentially, more discoveries and research are needed to reveal a clearer picture of the exact relationship between the families that connect butterflies and moths.
Nevertheless, if you are out and about it is best to remember the rules of thumb and to ignore those common misconceptions if you’re looking to get to grips with telling a moth from a butterfly.
Main image: Garden tiger moth © Getty Images
