Homes across the United Kingdom are experiencing an unusual influx of ladybirds as cooler autumn temperatures prompt the insects to seek sheltered locations for winter. Experts identify many of these visitors as harlequin ladybirds, an invasive species that has become prevalent in Britain since its arrival in 2004.
These ladybirds are larger than native species and may deliver a bite if handled, though it typically results in a minor red mark. As the weather cools, the insects search for dormant sites, and houses offer the warmth and protection they need. John Whiteley-Wilkson, managing director of Acorn Environment Services, notes that while the numbers can seem alarming, it is normal behavior as the insects seek safe, dry places to overwinter.
The dramatic appearance of numerous ladybirds is often because they do not hibernate alone. They frequently gather in large groups, leading to dozens congregating on a single wall or window frame. "It's completely normal for ladybirds to gather together before hibernation," Whiteley-Wilkson stated, adding that this seasonal behavior should not be mistaken for a pest infestation.
Homeowners often first notice ladybirds on south-facing walls, which absorb more solar heat during the day, helping the insects conserve energy. "You'll often notice ladybirds gathering on the warmest side of a property," an expert explained, as they utilize any remaining warmth before temperatures drop further.
According to the Natural History Museum, harlequin ladybirds are particularly known for entering buildings in autumn. Max Barclay, a senior curator of beetles, described harlequins as distinctive, with various color forms ranging from red with black spots to orange or black with red spots. A key identifier is their underside: most harlequins are orange underneath with orange legs, unlike native species which typically have black undersides and legs.
Harlequin ladybirds can carry a fungal infection called laboulbenia, which affects their wings. However, this fungus is specific to ladybirds and does not infect humans.
These insects typically enter homes through small gaps around windows. Experts advise against killing them, as squashing them can release a slightly smelly yellow secretion that may stain walls. Instead, it is recommended to help them find a way out of the home. Barclay suggested that released ladybirds might even help by consuming greenflies from roses.
To prevent ladybirds from entering homes, experts recommend sealing small gaps around doors, windows, and air vents. "Ladybirds aren't trying to invade your home – they're simply looking for somewhere protected to spend the winter," Whiteley-Wilkson concluded. "Preventing them from getting inside is usually just a case of sealing the small gaps they use to enter."