Rose Chafer

• GeneralA metallic green beetle, very common on roses and elder blossom.
• It flies with its elytra closed, pushing its membranous wings out through side grooves, something very few beetles do and that gives it a fast, noisy flight.
• As a defence it excretes uric acid and formic acid from the anal cavity, which give it a smell its predators find unpleasant.
• Its mandibles are reduced: it cannot chew as carnivorous beetles do and is limited to pollen, nectar, petals and soft fruit.
• Its metallic green is not a pigment but structural colour: the cuticle is made up of layers of chitin arranged in a helix that reflect light selectively.
• And there is a striking optical detail: it reflects left-handed circularly polarised light, a property that is vanishingly rare in nature and well understood only in this group of beetles. Whether it has a biological function or is a by-product of the structure is still debated.
• It flies without opening its elytra. Unlike almost all beetles, it has a lateral notch that lets it slip its wings out while keeping the elytra closed, giving it a fast, stable flight more like a bumblebee's.
• Its larva is a useful decomposer: it lives in compost and rotten wood and speeds up the recycling of organic matter, so it is best not to remove it from compost bins.
• The adult eats pollen, nectar and ripe fruit, and is an occasional pollinator.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat and environment

Gardens, flowery meadows and woodland edges

Litter / clutch size

The female lays her eggs in decaying organic matter and then dies. The larvae overwinter in the same place where they fed and pupate in June or July

Sources consulted: Natural History Museum (Londres) · Fauna Europaea · Asturnatura · Società Entomologica Italiana · El medi natural del Bages i del Moianès

Best time: From April to September, mainly from May to July and on sunny days