Species Statement

The rainbow leaf beetle is a species of montane grassland. The larvae and adults feed on wild thyme, preferring flowers to leaves. During the day, larvae have been found on plants growing in deep, narrow crevices between large boulders, and under stones lying on the grassland surface. Adults are found between April and September, and oviposition occurs during June. In captivity, eggs were mainly laid towards the tip of, and in parallel with, grass blades. On Snowdon, larvae have been found in September and October, also suggesting that this is the main overwintering life stage. However, the presence of fecund adults in April, suggests overwintering as young adults as well as larvae.

The species is known in the UK only from Caernarvonshire. There are post-1980 records from 6 one km squares, four on Snowdon and two on Cwm Idwal. The site on Snowdon where most adults have been collected is at 630 m above sea level, with a westerly aspect. Here it is considered well established, with one recorder estimating a population of perhaps 1000 individuals in about 1978. Generally, populations remain sparse, in spite of extensive searches. However, this is a difficult species to locate in the field and there is no reliable evidence of decline. This species is widespread throughout northern, central and southern Europe, including the Mediterranean region.

In Great Britain this species is classified as Endangered. The rainbow leaf beetle is specially protected under Section 5 of the Wildlife and Countryside Act 1981.

Not known.

Both Cwm Idwal and Yr Wyddfa (Snowdon) are NNRs.

CCW has trialled several monitoring strategies on the Snowdon population in recent years.

ITE has been observing this species as part of its investigations into the effects of climate change on the distribution of montane invertebrates.

No local implementation.

Originally published in: UK Biodiversity Group Tranche 2 Action Plans - Volume IV: Invertebrates (March 1999, Tranche 2, Vol IV, p140)