Beetles in the Endomychidae, Lucanidae (stage beetles) and Curculionidae (weevils) families
There are 8 species of beetle in this family in Britain. They are all related to, and resemble ladybirds/ladybugs. The adults live on fungus, especially puff balls and moulds.
Endomychus coccineus on the left and right, is 4 - 6 mm long as an adult, but not as convex as a ladybird, and its antennae are different. It is fairly common in Britain, especially near woodlands and fungus-infested wood, giving it its common name, the Fungus beetle. The larva is brightly coloured and feeds on wood fungus.
Lucanidae Family, Stag beetles
There are around 1300 species of stag beetle worldwide, and 4 British species. They get their name because the massive mandibles of the male (see below) resemble the antlers of a stag, and are used in a similar fashion - for defence and resolving disputes over females.
They have elbowed antennae. The males are always larger than the females. They range in size from 0.6 - 8.5 cm. The adults are nocturnal and either do not feed, or feed only on fluids such as nectar. Adult beetles have a particular fondness for sweet substances. In olden days they were called "cherry eaters", and will lick sweet sap from trees with their feathery tongues. In Northern Europe good sources of sweet sap can become favourite mating sites as numbers of beetles gather together.
The Lucanidae larva (right) lives in the root stock of deciduous trees especially oak, ash, beech elm and hawthorn, and can take 5 years to develop.
It has been found that ginger attracts stag beetles, both larvae and adults (as well as many other insects.
Stag beetle, Lucanus cervus
The stag beetle (left) is now rare, and in the U. K. is mainly confined to south-eastern England. Adult males can reach up to 75 mm long, making it the largest European beetle. The adult females reach up to 50 mm long.
The adults fly at dusk in July making a whirring sound with their wings just before take off and landing. The flight speed has been recorded at 1.5 metres per second. Compare this with other insects.
At the end of summer the adult female beetle will search for some suitable dead wood in which to lay her eggs.
The larvae eat rotting wood, and in the U. K. oak is the wood of choice. The larval stage can last as long as 6 years. The larvae can stridulate by rubbing the 2nd and 3rd leg together, and it is thought that this is a means of communication.
Lucanus lunifer, below. A stag beetle is from India.
Above an Indian stag beetle, Lucanus lunifer
Curculionidae Family, weevils
There are over 50 000 species of weevil world wide, 1 200 in Europe, and 475 in Britain. Many are considered pests, e.g. the vine weevil, left, the granary weevil (below), the cotton boll weevil, the grain weevil and rice weevil.
All Curculionids are vegetarian - mainly on plants, but a few eat fungus, and just a few are predatory. The females lay their eggs inside a plant by biting a hole first, or on their foodplant. Most adults have the characteristic snout (also called the rostrum) with jaws at the end, and elbowed, clubbed antennae extending from the snout (see left and below) usually with 11 segments. Adults range in length from 1 - 40 mm. The larvae (below right) generally live in plants are are usually short, round, fleshy, legless and milky coloured. The adults generally feed on the outside of plants. Many are decorated with colourful scales which tend to rub off with age.
On the left is Otiorhynchus sulcatus, the vine weevil. It belongs to the Curculionidae family. The adults are dull black with small patches of dirty yellow on the elytra. The adults are flightless. The adults range in size from 8.0 - 10.5 mm.
They are slow moving and usually active after dark. Sometimes an adult will be found on the inside of a closed window when you get up in the morning. This probably means that you have an infested indoor pot plant. If you re-pot the plant you may find 10s - 100- of fat grubs. Don't throw them out. Put them in a dish and leave them out for the blackbirds - they love them! The larvae feed below the soil surface and the adults eat the leaves. Most vine weevils are females and they can reproduce parthenogenetically - so no need for a male or sex. The eggs are usually laid on the soil surface. Ground beetles are a major predator, as are commercially available nematodes.
On the left is Phyllobious sp. another weevil. Like many weevils it is covered in colourful scales. These can wear off with age leaving black patches.
The drawing on the right shows the typical body shape of a weevil larva.
On the right is an adult granary weevil or grain weevil, Sitophilus granarius. It is a pest of stored grain, and its body length is 2.3 - 3.5 mm. Adults emerge from a grain, then mate - they cannot fly, so a mate is found by walking. The female drills a hole in a grain and lays a single egg, then plugs up the hole. The egg hatches and the larva begins to eat its way through the grain. It pupates inside the grain, and then emerges as an adult to start the cycle again.
A female can lay up to 250 eggs at a rate of 2 - 3 a day. The length of life cycle depends on temperature, but is 30 - 40 days in summer and 120 - 150 days in winter. A single breeding pair can give rise to over 6000 beetles in a single season if the conditions are right. In the U. K. it cannot breed outside.
Sitophus granarius is sometimes placed along with some other grain weevils in a separate family called Dryophthoridae or Rhynchophorinae.
On the left is Phytobius waltoni, a tiny, 2 mm long, aquatic weevil that lives on aquatic plants.
Hylobius abietis, the Pine weevil, Large pine weevil, and spruce weevil
On the left is an adult Pine weevil, also sometimes called the Large pine weevil or Spruce weevil. The body length is from 8 - 14 mm. It is common in Scotland, but less common in England. Adults are seen mainly from April to June. Females lay eggs on pine and spruce roots, although they can also eat larch. The adults prefer trees less than 6 years old, and can cause the death of a young tree, so are considered a pest.
The photograph on the right is a close-up showing the long, yellow, hair-like scales on the elytra.
The larvae feed on the inner bark and then the sap wood, and pupate inside the tree. They can grow up to 18 mm long.