Ladybirds feature ‘aposematic’ or ‘warning colouration’ that gives potential predators advanced warning of their bad taste, and when threatened, they can exude a toxic and foul-smelling alkaloid liquid from their joints. But in spite of their excellent defence system, ladybirds are not without enemies; parasitic wasps and flies occasionally attack them and some ladybirds fall victim to intrepid spiders and toads too.
Many native ladybird species are under threat from another ladybird species – the Asian or harlequin ladybird (harmonia axyridis). These invaders are generalist feeders and can out-compete resident ladybirds in their native range. They’re also somewhat infamous for attempting to hibernate inside human dwellings where they may swarm, stain fabric and even cause allergic reactions.
Currently one-fifth of indigenous British ladybird species are on the decline. In addition to competition with the aforementioned Asian ladybird, climate change and altered land use patterns are likely contributors.
Not all the news is bleak however – a few native ladybirds are expanding their range, and one species – the 13- spot ladybird – previously thought to be extinct has recently been found in Cornwall and Devon.