Click beetle (Lacon quercus)
| Synonyms: | Adelocera quercea, Agrypnus varius |
|---|
| Kingdom | Animalia |
|---|---|
| Phylum | Arthropoda |
| Class | Insecta |
| Order | Coleoptera |
| Family | Elateridae |
| Genus | Lacon (1) |
| Size | Length: 10 - 12 mm (2) |
Classified as Endangered in Great Britain (3).
This click beetle is generally brown in colour, with yellowish blotches and flecks, and a yellow band passing across the far end of the wing cases (elytra) (4). Like all click beetles it has a 'spring' device underneath the body, which allows it to flip into the air should it fall onto its back. This feat is accompanied by an audible 'click', referred to by the common name of the family, click beetles (5).
This species was first recorded in 1830, and was not seen again for around 100 years (6). In Britain, it is currently found only in Windsor Forest and Windsor Great Park (7). Elswhere, the species is 'scarce and sporadic' in central Europe (6).
Associated with red-rotten wood on veteran oak trees and fallen branches (7), it inhabits ancient broadleaved woodland as well as pasture-woodlands (1).
This click beetle breeds in standing and fallen dead oak trunks and boughs, however it does not breed in stumps (6). It is thought that the larvae are predatory, feeding on the larvae of other beetle species, such as Mycetophagus piceus. When the larvae are fully developed towards the end of the season they pupate. The adults then hibernate inside the cell formed by the pupa. After emerging, they are nocturnal (6).
All beetles that depend on dead wood habitats are threatened by the loss of old woodlands and parklands, due to development or agricultural expansion. Old trees and fallen dead wood are often removed from woodlands, reducing the available habitat for these beetles (7). Furthermore, the age structure of trees within sites may be skewed, and as a result, a constant supply of old wood may be lost (7).
This beetle is a priority species under the UK Biodiversity Action Plan (UK BAP); the group Species Action Plan that has been produced for 10 beetles dependent on dead wood, aims to maintain the current range of this species (5). Windsor Forest and Great Park are now managed in ways that retain dead wood habitats; there is also a non-intervention area in Windsor Forest (5).
The group action plan for saproxylic (associated with dead wood) beetles is available on-line at:
http://www.ukbap.org.uk
For more on English Nature's Species Recovery Programme see:
http://www.english-nature.org.uk/science/srp/default.asp
Information authenticated by Dr Roger Key of English Nature.
www.english-nature.gov.uk
- Elytra: in beetles and earwigs, the hard fore wings. They are held aloft when the insect flies, and are often coloured or patterned.
- Hibernate: a winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
- Larvae: stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Pupate: the process of forming a pupa, the stage in an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
- National Biodiversity Network Species Dictionary (September 2002) http://www.nhm.ac.uk/nbn/
- Key, R. (January, 2004) Pers. comm
- Shirt, D. B. (1987) British Red Data Books: 2 Insects. Nature Conservancy Council, Peterborough.
- Personal observation from images.
- Harde, K. W. (2000) A field guide in colour to beetles. Silverdale Books, Leicester.
- Cheesman, O.D (2003) (unpublished). Research on saproxylic invertebrates and their conservation in the UK (contract FST 20-37-02) Final report. CABI report xB1992. CABI Bioscience. Egham Surrey.
- UK BAP (September 2002) http://www.ukbap.org.uk