Bill Grange
The picture changed greatly in the two years following 2005, with the harlequin steadily moving up-country and increasing greatly in numbers. The midlands were thoroughly colonised, with the invasion eventually spreading up into the north of England and invading Scotland.
Because it preys on a wide range of other insects, and has no known enemies of its own, the Harlequin threatens to cause an ecological imbalance of who knows what extent. In North America, where it was also introduced as a pest control agent, it is now the most common species of ladybird.
The picture here will help you identify the Harlequin, but the insect is extremely variable, so a list of defining characteristics will be helpful:
1. They are relatively large (6-8 mms), the length of the
Seven-spot ladybird (our commonest native species), or slightly longer.
2. Their bodies are distinctly rounded.
3. Their legs are brown (only partly in melanic specimens).
4. They may have 0-19 black spots on red or orange or two
or more red patches on black.
5. Their heads have a conspicuous white marking with a
small triangle in the centre - which remains on the melanic specimens.
6. Their pronota (front part of thorax) have a lot of white, the side margins remain
on melanic specimens.
The website of the National Harlequin Survey (yes, there is a government funded 'department' devoted to monitoring the spread of the species) is most helpful in identification and for the latest information on the current situation.
Go to:
Early in June of 2011, I noticed that a pupa of the harlequin - on nettles - on the margin of the field near the Evergreen Hall entrance was being examined by a tiny braconid wasp (related to the better known ichneumon wasps).On taking some close-up photographs, it was clear that the wasp was circling the pupa and periodically stabbing it with its egg-laying tube (ovipositor). Like ichneumons, braconiods lay their eggs inside the bodies of other insects. The larvae which hatch feed on the living tissues of the host, eventually causing the former's death. In this case, instead of a ladybird, a braconid wasp emerges. A few days later Ii collected the pupa and brought in home, putting it in a container and waited to see what happened. After a week or so, I saw the characteristic yellow larva of the braconid wasp on the surface of the harlequin pupa. Hoever, no adult wasp eventually emerged.
Helen Roy of the National Ladybird survey was quite excited by this observation, as very few people have seen harlequins being the victim of the parasite, which normally attacks our native ladybirds. It does provide some hope that tables may be being turned on the the alien harlequin.
PICTURE: Oon the left is of the braconid attacking the pupa - it shows the wasp in the act of bending its abdomen under its legs and driving its ovipositor into the pupa at the weak point between the upper and lower plates. On the right is a drawing of the braconid wasp Dinocampus coccienllae.
PICTURE: Harlequin Ladybird: A larva (centre)- with its bright orange processes on the abdomen, with two colour forms of the adult - succinia and conspicua - showing how variable it can be.
On a fence post at Woodlands field, Allestree Park, 18th October, 2011 by Bill Grange
UPDATE - October, 2011:
During the inconsistent summer of 2011, the Harlequin seems to have made a modest comeback, though it was overwhelmingly outnumbered by our native seven spot ladybird. If we have a mild winter, I expect the harlequin to start builing up it numbers to 2005 levels.
UPDATE - April 2012:
We did indeed have a mild winter - and this has been reflected by a slight increase in the number of sightings of Harlequin Ladybirds in the Park. However, it is still greatly out-numbered by the native Seven-spot Ladybird.
Harlequin Ladybird - Harmonia axyridis form conspicua
A fairly uncommon form of the Harlequin ladybird
Allestree Park, near Woodlands Lane Car Park, 20th April 2012 by Bill Grange
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