Swollen-thighed beetle

A glittering green swollen-thighed beetle on a leaf, demonstrating the chunky thighs that earn its name

Male swollen-thighed beetle © Tom Hibbert

A male swollen-thighed beetle feeding on the pollen of a bright yellow flower

Male swollen-thighed beetle © Chris Lawrence

Swollen-thighed beetle

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Enw gwyddonol: Oedemera nobilis
This metallic green beetle can be seen visiting flowers on sunny days in spring and summer.

Top facts

Stats

Length: 6-11 mm

Conservation status

Common

Pryd i'w gweld

April to September

Ynghylch

The swollen-thighed beetle is also known as the thick-legged flower beetle, and it just takes one look at a male to see why — they have huge green bulges on the femora of their hind legs. They were once only found in a few parts of southern England, but have expanded and are now much more widespread, including throughout Wales.

Adult beetles emerge in spring and are most likely to be seen on warm, sunny days. They feed on pollen and visit a range of open-faced flowers, making them excellent pollinators. You will often find them on umbellifers, brambles and oxeye daisies. As a result, swollen-thighed beetles can be seen in just about any habitat that offers plenty of suitable flowers. The larvae of this beetle are rarely seen as they live inside the stems of thistles and other plants.

What to look for

A medium-sized, bright, metallic green beetle that can show a golden or coppery sheen. The wing cases (called elytra) are narrow and don't quite meet in the middle, leaving an obvious gap with the wing membrane below exposed.

Males are instantly recognisable thanks to the large green bulges on the femora (thighs) of their hind legs. Females don't have these and could be mistaken for other similar species, but can be distinguished using the features mentioned above.

Where to find

Widespread in Wales and southern England north to the Midlands.

Roeddech chi yn gwybod?

They are also sometimes known as false oil beetles.

Gwyliwch

Slow-motion clip of a swollen-thighed beetle taking flight © Tom Hibbert