Halloween Harlequins

It’s dark outside and you, dear reader, are settled inside for the night. In the corner of your eye you notice a movement. Do you see it? There, lurking by the windows. It’s only small but as you turn your head you realise that there are many of them. The mass appears almost liquid-like as the creatures crawl up and over each other. As you move closer to inspect the source of your curiosity, you feel something hard hit your cheek. Suddenly unconfident, you reach for the light switch, the main light comes on and everything stops! The tight mass that previously was moving can now be clearly seen as a mound of red, orange and black. What are they? They my curious friend are ladybirds, Harlequin ladybirds (Harmonia axyridis), and generally not the source of nightmares.

Four of the hundred or more Harlequin ladybird colour pattern varieties
can be seen at the bottom of our FSC guide.

Alternatively known as the Halloween Ladybug in America - as they often appear in people’s homes around Jack-o’-lantern carving time - homes all around the UK, including FSC Preston Montford, are seeing an influx of these insects colonising the cosy corners by the windows and walls. This season’s abundance is likely induced by the continuous high temperatures over the summer. First arriving on our shores in September 2004, the Harlequin ladybird is native to central and eastern Asia (Kuznetsov, 1997). They were used as a biological control agent for aphids in North America due to their predatory efficiency and ability to colonise a range of habitats (Majerus, M. et al., 2006).

Unlike our native ladybirds that generally hibernate in trees or leaf litter (BBC News, 2018), the Harlequin ladybird prefers to over-winter in our warm buildings. So, does this resident pose a problem to us? For the most part, no, these ladybirds are generally harmless and can be left where they are (BBC News, 2018). If aggravated, the Harlequin ladybirds exude a defensive chemical from their joints which has an unpleasant smell and can stain soft furnishings (Majerus, M. et al., 2006). Not a trick you want played on you this Halloween! One of this ladybird’s favourite treats is the sap from fruits such as pears and apples, which help to build up the Harlequin’s energy reserves but could leave your fruit blemished (Majerus, M. et al., 2006) – maybe cover up your fruit bowl if you notice them taking an interest.

So what can you do until they awake from their slumber and head back into the garden? Well, you can upload your sightings onto iRecord so scientists can monitor the distribution of this invasive species. More information can be found on monitoring UK ladybirds at: http://www.ladybird-survey.org/default.aspx. Alternatively, you can make up your own ghoulish story about the ladybird lodger that appeared unannounced. We’re doing both with ours…Happy Halloween!

Sources

BBC News (2018) Harlequin ladybirds swarm into homes after hot summer. Available at: https://www.bbc.co.uk/news/uk-45766496 [Accessed on: 29^th October 2018]

Majerus, M. , Strawson, V. and Roy, H. (2006), The potential impacts of the arrival of the harlequin ladybird, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in Britain. Ecological Entomology, 31: 207-215.

Kuznetsov, V.N. (1997) Ladybeetles of Russian Far East. Memoir Seis Editor, CSE, Gainesville, Florida.