just hatched Harlequin Ladybird larvae
Harlequin larva eating aphid
harlequin ladybird eggs
The Harlequin Ladybird is a recent arrival to the UK, but it is already very common in southern England. It loves to overwinter in large numbers in nooks and crannies of houses where it becomes a considerable nuisance. Although it rapaciously devours many garden pests, it is generally considered 'a bad thing' because, when pests run out, it apparently turns on the native British ladybird. Having watched a Harlequin larva feast on one of its own siblings (photo below), I can well believe the smaller British relatives would stand no chance,
However, my greenhouse has plenty of aphids, and I could see no reason against moving a number of adult Harlequins out of a relative's house and into my greenhouse. This is a photographic record of what happened.
The adult Harlequins soon seemed to disappear, but I then noticed a patch of red eggs on an aphid infested citrus where I had released them. A few days later, the black larvae emerged, leaving crumpled, white egg sacks behind. Eggs and the just-hatched larvae are about Imm long.
full grown Harlequin Ladybird larva
The larvae grew rapidly on a plentiful diet of aphids, shedding their skin several times, and developing prominent red markings.  On one occassion, an adult larva was observed  feeding on another of similar size! Length finally about 8-10mm before pupating.
adult Harlequin Ladybird
....friend or foe?
Harmonia axyridis
page created 11th May 2008
Cannibal Harlequin larva
Here is a pupating larva attached to the underside of a leaf, about 4 weeks from hatching. The adult ladybird emerged a week later. To my surprise it had no markings - they were left behind on the discarded pupa case. I'm not sure whether the adult ladybird developed markings in the next few hours. When I searched the next day, I couldn't find a ladybird without spots!
adult Harlequin Ladybird leaving pupa
Harlequin Ladybird and pupa case
Harlequin pupa
spotted Harlequin pupa