Norwich scientists have thanked EDP readers for helping to establish a new research colony of the harlequin ladybirds which swarmed across the region last year.

After many people reported their homes being invaded by the invasive beetles during the hot summer, the entomology team at the John Innes Centre issued a public appeal to find over-wintering clusters of them which could help their research.

They said the EDP coverage led to a 'very strong response', keeping researchers busy following up sightings of the insects found clustering in sheds, outhouses, and homes around East Anglia.

With the colony now fully re-stocked, head of entomology Dr Ian Bedford thanked the public and explained why ladybirds can be so important for research to protect crops and beneficial insects in the wild.

'We maintain a ladybird colony within the insectary because they are an important group of aphid predators, vital for maintaining a balanced environment,' he said. 'Commercially they are an extremely useful 'natural enemy', helping with crop protection and integrated pest management programmes.

'When new crop protection products, ideas and strategies are under investigation, it is essential that effects on beneficial invertebrates are investigated.

'We are often involved in these types of experiments and ladybirds play an important part of this research.'

The harlequin is an invasive species, from eastern Russia, China and Japan, which has rapidly spread across the UK over the last 15 years.

This migration initially caused concern that this new species could displace native ladybirds, but Dr Bedford said these concerns have so far been unfounded because the harlequin has native predators which keep its numbers down.

The harlequin varies in appearance making it difficult to distinguish from native species but, unlike native ladybirds, the newcomer often hibernates in large clusters over the winter which makes it relatively easy to collect.

'The harlequin is a perfect candidate species for keeping as a laboratory colony under controlled conditions as it is robust, highly fecund and easy to maintain,' said Dr Bedford.

'However, it is important that every so often, we introduce individuals from other sources to the lab colony to diversify the colony's gene pool. We would like to thank the public and readers of the Eastern Daily Press for their help.'

With the colony now full, the John Innes Centre no longer needs more harlequin ladybirds.