Truth or Fiction?
They aren’t good for our native two-spots, but do harlequin ladybirds really pose a threat to our homes, pets or even ourselves? Helen Roy enlightens.
Are harlequin ladybirds really the villains that they have been made out to be?
THE GLORIOUS SUMMERS OF 2018 and 1976 have something else in common – ladybirds (and lots of them). In the 70s, it was native seven- and 11-spots. This time, it’s harlequin ladybirds – introductions from Asia – entering our homes en masse to overwinter.
If news reports are to be believed, this ‘cannibalistic’, ‘STD-ridden’, ‘biblical plague’ is stinking out our homes, staining our furnishings, poisoning our pets, biting people, inducing allergic reactions and generally ‘wreaking havoc’. But are the reports to be believed?
Not according to ecologist Helen Roy, who explains that there may be little doubt that harlequins are having an impact on our wildlife – they eat and outcompete native two-spot ladybirds. “But from the human perspective, they are nothing more than a very minor nuisance,” she says.
True, some people might not like the smell, which derives from a yellow defensive secretion that can indeed cause stains. “All ladybirds have a slight taint to them,” says Roy. “If you have 200 in your window frame, it’s going to be stronger, but it doesn’t travel far. And hoovering them up probably makes it worse.”
But what if you’re allergic to them? “I’m sure every insect bite could produce an allergic reaction in some people,” says Roy. “But it’s so rare that I’ve only heard of two or three cases.”
Similarly, the chances of a pet being poisoned are vanishingly small. “The only case I’ve come across was a dog that got a mouthful of them.”
Neither will they be spreading sexually transmitted diseases. The fungal infection in question is, says Roy, “absolutely no risk whatsoever. It’s barely transmissible to other ladybird species, let alone anything else.”
The risk of bites has also been greatly exaggerated. “In all the decades I’ve been working with ladybirds, I’ve had one bite – from a seven-spot. I can’t begin to describe how minor it was.”
The only ones benefitting from the scare stories are pest controllers. “The great shame is that they could be harming other species as well. There’s no specific control method for harlequins, and two-spots also like to overwinter in houses.”
In all the decades I’ve been working with ladybirds, I’ve had one bite – from a seven-spot.
HELEN ROY
is an ecologist at the Centre for Ecology and Hydrology in Wallingford.