Harlequin Ladybirds
Identifying a harlequin ladybird
The harlequin ladybird (Harmonia axyridis) is also known as the Multicoloured Asian Ladybird and the Halloween Ladybird. These beetles can sometimes be difficult to identify because of their variations in color, spot size, and spot count. The easiest way to identify an Asian lady beetle is to look at the pronotum (upper surface of the foremost of the three segments) and see if the black markings look like a letter “W” or “M” (depending on if the marking is viewed from the front or the back). Identification chart.PDF (140kb)
Distinguishing the harlequin ladybird from other British species
•If its less than 5 mm (1/5 inch) in length, it is definitely not a harlequin ladybird.
•If its red with precisely 7 black spots, it is a 7-spot ladybird.
•If it has white or cream spots, it is a striped ladybird, an orange ladybird or a cream-spot ladybird.
•If it is large, burgundy coloured and has 15 black spots, it is an eyed ladybird
•If it has an orange pronotum, and fine hairs all over the elytra, it is a bryony ladybird.
• If it is black with four or six red spots, two of which are right at the front of the outside margin of the elytra (the fore wing), it is a melanic (mainly black) form of the 2-spot ladybird.
Description
• Size and shape : large (7-8 mm or about 1/4 inch), round
• Elytra (wing case) ground colour: pale yellow-orange, orange-red, red or black; highly variable
• Elytra pattern: 0-21 orange-red or black spots, or grid pattern; highly variable
• Most common forms in UK : orange with 15-21 black spots: black with two or four orange or red spots
• Pronotum pattern: white or cream with up to 5 spots or fused lateral spots forming 2 curved lines, M-shaped mark or solid trapezoid
• Other characteristics: elytra with wide keel at base; legs almost always brown
Behaviour
Harlequin Ladybirds hibernate in cooler months, though they will wake up and move around whenever the temperature reaches about 50°F (28°C). Because the beetles will use crevices and other cool, dry, confined spaces to hibernate, significant numbers may congregate inside walls if given a large enough opening. They often congregate in sunlit areas because of the heat available, so even on fairly cold winter days, some of the hibernating beetles will “wake up” because of solar heating. These large populations can be problematic because they can form swarms and hover in an area for a long time. Also, the bugs do not understand that glass cannot be penetrated by their small bodies, so many of the bugs will crash into window panes. These bugs will “reflex bleed” when agitated, releasing blood from their legs. The blood has a foul odor (similar to that of dead leaves) and can cause stains. It is believed that some people have allergic reactions when repeatedly exposed to lady beetles (especially dead ones). Sometimes, the beetles will bite humans, although many people feel a pricking sensation as a lady beetle walks across the skin. Bites are believed to do no more harm than cause irritation.
Concerns regarding effects on the UK environment
This species has begun penetrating the UK; first seen in 2004. It has now had confirmed sightings from the South East to the Midlands. This is of particular concern as the harlequin ladybird has the potential to jeopardise the native species due to it being a very effective aphid predator. When this food source becomes scarce, it will eat ladybird eggs and larvae, and butterfly/moth eggs and caterpillars.
What to do
Should I stamp on any harlequins I find?
No. It had already become too widespread and numerous in England before it was discovered for it to be eradicated. Killing them now will not affect its numbers and may lead to other insects mistakenly identified as harlequins being killed.
Do I have to report harlequin ladybirds?
There is no obligation to do so. They can be reported online to www.harlequin-survey.org, giving details of when and where the insect was found (include the postcode for a garden). Alternatively, specimens can be sent, preferably alive in a stout container, to: Ladybird Research Group, University of Cambridge, 219D Huntingdon Road, Cambridge CB3 0DL. For the record to be confirmed it is necessary to send either the insect or a clear photograph. When photographing the ladybird, it is helpful to include a ruler or coin in the picture to give an indication of size.
External Links
- The Harlequin Ladybird Survey
- Royal Horticultural Society - Gardening Advice: Harlequin Ladybird
- Elmbridge Borough Council: The Harlequin Ladybird
- DEFRA: The Harlequin Ladybird