Harlequin Ladybird

The Harlequin Ladybird (Harmonia axyridis) is one of the most invasive insect species in the world. To provide context: it took the Grey Squirrel 100 years to spread throughout the UK, and it took the Harlequin Ladybird less than a decade to do the very same.

The species was introduced to North America from Asia in the 1980s to help control aphids that were damaging crops. Thereafter, they rapidly became the most common species of ladybird in the North American continent. Due to the US success with them in aphid control, they were then introduced in Europe and arrived in Britain in 2004.

The Harlequin Ladybird is a voracious predator and will quickly move from feeding on aphids to other ladybird eggs and even the eggs and caterpillars of moths and butterflies. They can easily out-compete our native ladybirds for food and are thought to be the main reason for the increasing scarcity of the UK’s Two-spot Ladybird (Adalia bipunctata).

Harlequins are orange /brown on the underside and have orange legs. However, over 100 different colour patterns have been recorded which can makes them challenging to identify. Harlequin Ladybirds can have anywhere between 0 and 21 spots on their elytra.

The Harlequin Ladybird serves as an example on the potential negative impacts that invasive non-native species can have.

• Size: Up to 8.5mm
• Life span: up to 1 year.
• Diet: Harlequins will prey on aphids but will also eat other ladybirds, moths and butterfly eggs and larvae.
• Reproduction: The lifecycle consists of four phases: egg, larva, pupa and adult stage. Female ladybirds lay bright yellow eggs on the underside of leaves in clutches of up to 40, usually in June and July. Harlequin Ladybirds can have multiple broods throughout March-October, which gives the species another competitive edge against native ladybirds.
  
• When to see: March to November. It is now one of the most common species of ladybird that we see in our towns and gardens.
• Population Trend: Increasing
• Threats: Not known.
• Interesting Fact: In North America, the Harlequin Ladybird is sometimes known as the ‘Halloween bug’ because it congregates in large numbers during autumn.

How can you help:

Submit your ladybird sightings to the UK Ladybird Survey. By building up a database of records, we can better understand how ladybirds are responding to threats like the invasive Harlequin. You can submit your ladybird sightings on iRecord.

While it can be hard to distinguish Harlequin Ladybirds from native ladybird species, the UK Ladybird Survey offers the following advice in identification:

• If it is less than 5 mm 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, it is a melanic form of the Two-spot Ladybird.

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You might also be interested in

Two-spot Ladybird

Adalia bipunctata

Seven-spot Ladybird

Coccinella septempunctata