Wednesday, 14 September 2011

Ladybirds get their own atlas


It is at this time of the year that I start to notice ladybirds around the house. Most of these are the Harlequin Ladybird, a non-native species whose arrival in 2003 resulted in a rapid and worrying colonisation of most of England and much of Wales. That we have been able to chart the spread of this species is largely down to the organisers of two national ladybird survey schemes: the Harlequin Ladybird Survey (www.harlequin-survey.org) and the UK Ladybird Survey (www.ladybird-survey.org). Because most ladybirds are large, colourful and recognisable (as being a ladybird), the surveys have been able to tap into people’s enthusiasm for these insects. Submit a record of a ladybird, perhaps with a photograph and perhaps of a species you do not recognise, and you’ll receive an identification and have your record added to the ladybird dataset.

Eyed Ladybird

The efforts of all this hard work have just been published in a new ladybird atlas, which not only reveals where the different species occur, but also gives pointers to their identification, seasonality and habitat preferences. Flicking through the atlas reveals the presence of many ladybird species in Norfolk that are easily overlooked. In fact, it might surprise many readers to discover that there are 47 ladybird species in the UK (and more than 4,500 worldwide). Roughly half of our ladybird species are instantly recognisable as being ladybirds, with brightly coloured and spotted elytra (the hard wing cases that form the back of the ladybird). The remainder are typically small, dull in colour and readily dismissed as being some other form of small beetle, unless you know what to look for.

The arrival of ladybirds in the house suggests that the season is changing and that the ladybirds are preparing for the tough times ahead. The unfavourable winter weather and scarcity of food, prompts ladybirds to enter a dormant state, often in aggregations of a dozen or more individuals. Most enter this period of dormancy towards the end of September, remaining in this state until the warming days of spring.

Many of our ladybirds are associated with particular plants, where they feed on aphids and scale insects. Knowing these preferences should allow you to seek out individual ladybird species, from the gorgeous Orange Ladybird, which favours Ash and Sycamore, to the narrow-bodied Water Ladybird associated with reeds and other waterside vegetation. Others can be swept from low vegetation with a net or sought on the trunks of Larch.

For a budding naturalist, the ladybirds form an excellent group. There are not too many species; identification is not that difficult and you can quickly make a very valuable contribution to our knowledge of the distribution and habits of these beetles.

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