Ground beetles and rove beetles

What are they?

Ground beetles (Carabidae) and rove beetles (Staphylindae) are families of beetles which are largely ground dwelling, most are predatory and so should be considered gardener’s friends: Adults and larvae of many species in these families eat insects, slugs and other invertebrates. There are about 350 species of carabid and 1000 species of staphylinid beetles in Britain.

These beetles can be encouraged in gardens by providing habitats for wildlife particularly wood piles, compost heaps and leaving some leaf litter in gardens borders.

Rove beetles have elongate bodies with short wing-cases that leave most of the abdominal segments uncovered. They are 2-30mm (up to 1¼in) long and most are black or brown in colour, but some have red wing-cases and markings. The matt black devil’s coach horse (Ocypus olens) is Britain's largest rove beetle and is often found in gardens under logs or pots. A smaller species, Atheta coriaria, is sometimes supplied as a biological control agent for fungus gnat larvae, glasshouse red spider mite and aphids in glasshouses.

Ground beetles are 2-25mm (up to 1in) long many are black but some are brown, green or blue, often with a metallic sheen. Most feed at ground level, but some will climb plants to feed on aphids and small caterpillars. One common garden species, the violet ground beetle (Carabus violaceus), has metallic-purple edges to the wing-cases and thorax. Being one of the bigger carabids, 20-25mm long, it will feed on some of the larger garden invertebrates, including slugs, leatherjackets, cutworms and other caterpillars. Its long legs and powerful jaws mark it out as an active predator.

Biology

Ground beetles and rove beetles typically;

• Lay eggs in the soil or in accumulations of organic matter
• Have larvae which are elongate, relatively soft-bodied and have three pairs of legs near the head end
• The head, thorax and usually some of the abdominal segments of larvae are often brown or black but the underside is creamy white
• The larvae generally remain in the soil or leaf litter, where they feed on small invertebrates and their eggs
• As adult beetles, especially ground beetles, they are much more active and may be seen running over the soil surface

See also...

Aphids
Aphid predators
Biological control
Earthworms
Earwigs
Encouraging amphibians
Encouraging garden birds
Encouraging moths into your garden
Fungus gnats
Harlequin ladybird
How Gardeners can help declining bees and other pollinators
Ladybirds
Millipedes
Pollinators: Decline in numbers
Wildlife in gardens