Six-spotted pot beetle  (Cryptocephalus sexpunctatus)

Six-spotted pot beetle

Facts

Kingdom Animalia
Phylum Arthropoda
Class Insecta
Order Coleoptera
Family Chrysomelidae
Genus Cryptocephalus
Size Body length: 4.5 - 6.5 mm

Status

Classified as Vulnerable in the UK.

Description

This shiny beetle has a yellow thorax and yellow wing-cases, which are each marked with three black spots. However, despite the common name, the number of spots on each wing-case may vary from three to four.

Range

From historical records, this appears to have been a widely scattered species in the UK. There are records from Ayrshire and Dumfriesshire in Scotland, Wiltshire, Dorset, Hampshire, East and West Sussex, Essex, Suffolk, Gloucestershire, Worcestershire, Warwickshire and Lincolnshire. Since 1970 however, there have only been sightings in Essex, West Sussex, Hampshire and Kirkcudbrightshire, with only a single recent record coming from Kirkcudbright in 2000. Elsewhere, this species is found in northern, central and southern Europe.

Habitat

The six-spotted pot beetle is a species of scrub margin on calcareous grassland and woodland edge, and has been found on hazel, birch, aspen, crack willow, hawthorn and young oak. It has also been found on the flowers of wood spurge. The species possibly occurred previously in coppiced woodland.

Biology

Adult beetles emerge around mid-May to mid-June, and the females lay their eggs whilst perched in low foliage. Each egg is held between the hind legs and a 'pot' made around it with the beetle's own droppings. This pot is then dropped into the leaf litter under the bush. The eggs hatch within three to four weeks. The larvae also construct pots for themselves out of droppings and this is thought to act as a defence mechanism. When danger threatens the larva retreats into its pot. Before pupation, the larva seals the pot. The adult beetles emerge from their pots, after a total development period of between 12 - 21 months, by cutting a hole at one end.

Threats

The main threats to this species are the lack of management of its preferred woodland. The cessation of coppicing probably contributed to the beetle's earlier decline.

Conservation

The six-spotted pot beetle is listed in the UK Biodiversity Action Plans and included in English Nature's Species Recovery Programme. It is important that more information is gathered about this species' habitat requirements and its ecology, as well as the other members of the Cryptocephalus group of leaf beetles. It is also possible that other populations still exist within the beetle's historical range, and a number of surveys are being carried out to assess the true status of the species.

Information supplied by English Nature:

http://www.englishnature.org.uk/

Antennae: pair of sensory structures on the head of invertebrates.
Calcareous: containing free calcium carbonate, chalky.
Coppiced: coppicing is a traditional form of woodland management in which trees are cut close to the base of the trunk. Re-growth occurs in the form of many thin poles. Coppiced woodlands are cut in this way on rotation, producing a mosaic of different stages of re-growth.
Thorax: part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.