Ten-spotted pot beetle  (Cryptocephalus decemmaculatus)

Classified as Vulnerable in the UK.

The ten-spotted pot beetle has the typical 'beetle' shape and comes in two colour forms: one is almost pure shining black; the other is yellowish-orange in colour, with a black head and antennae, as well as black edging to the yellow thorax, which has four black spots. There are five large black spots on each of the two yellow wing cases. The whole body has a shiny appearance.

This is a widely distributed species across northern and central Europe, but in the UK it has a curious distribution. It has been recorded from Rannoch and Braemar in Scotland, and from Staffordshire and Cheshire in England. There is also a record from the nineteenth century in East Sussex. It is currently known from only two sites, one each in Scotland and England.

You can view distribution information for this species at the National Biodiversity Network Gateway.

The beetles have been found on sallows and birch trees growing in bogs.

The adults are active beetles, and fly or drop to the ground when disturbed. The eggs are also dropped to the ground, in 'pots' formed from the female beetle's droppings. The larvae also live in pots, and feed on fallen sallow leaves. They take about a year to develop.

The ten-spotted pot beetle is threatened by inappropriate drainage schemes, and the loss of the natural woodland on their wetland habitat. Habitat fragmentation seems to be a very significant threat. Although adult beetles are active fliers they seem to be very poor at dispersing, and there is little evidence that they readily colonise new habitats, even over short distances. Genetic studies have revealed there is very little gene-flow between populations.

The ten-spotted pot beetle is listed in the UK Biodiversity Action Plan (UK BAP), and included in English Nature's Species Recovery Programme. The areas where the beetle is currently known to occur are either National Nature Reserves (NNRs) or Sites of Special Scientific Interest (SSSIs), and research on this species and others in the genus Cryptocephalus is being carried out at the University of Leeds. Work is under way to re-establish an additional population at a former site in Staffordshire. Whilst the beetle's numbers continue to be monitored, its future will be linked to the action plan for lowland raised bogs, its favoured habitat.

The UK Biodiversity Action Plan for this species is available at UK BAP.

There may be further information about this species available via the National Biodiversity Network Gateway.

Further information:
http://www.coleopterist.org.uk