Despite the rain and chilliness of the last three months, ladybird larvae have appeared at almost the same time as they did in 2010. Back then, the first sighting was on the 12th of July and this year I spotted the first one on the 18th of July. But,it wasn’t a British ladybird larva, it was a harlequin ladybird (Harmonia axyridis) larva, an invasive species which has been spreading north and west throughout the UK since it was first sighted in the south east of England in 2004.
Harlequin ladybird larva
It’s interesting to look at the difference between the two. The native larvae are a paler grey than harlequin larvae and the harlequin larvae are noticeably spiky looking, with much longer legs.
Native UK ladybird larva
Finding the harlequin ladybird larva sent me on a search in the garden at home, where we have broad beans growing, broad beans with aphids on them. Sure enough, there were dozens of ladybirds of all types, both the UK ladybirds and harlequin ladybirds. They were all busy – some were eating aphids on the leaves and pairs were mating on the stems. Mating ladybirds should mean eggs, so I started checking the underside of the leaves and found half a dozen clusters of upright, yellow to orange, pointy oval eggs, each about 1mm long. Some of the egg clusters were darker than others and it remains to be seen if the reason is the age of the eggs or that a different species of ladybird laid them.
The eggs should hatch within 1-2 weeks and the larvae will then get busy eating as many aphids as they can get hold of and, during the 3-4 weeks of this stage of life, the larva will consume up to 500 aphids. This gives it the energy to metamorphose into its next form and it attaches itself to a leaf and becomes a pupa. Within the pupal case, the adult ladybird is forming and will emerge in August. All being well, it will continue eating aphids until the autumn cold sends it into hibernation until the following spring.
A ladybird pupa attached to a nettle leaf.
You can find out more about harlequin ladybirds at The Harlequin Ladybird Survey.