Adalia decempunctata (Linnaeus, 1758)

Abundant and usually very much so throughout the British Isles in most types of habitat; in summer the adults are highly adventitious although in general they tend to be more arboreal than the two spot. They appear during the first warm days of March and from then are common, increasing in numbers as the warm weather proceeds, by late July or August they are found in numbers everywhere. Beating or sweeping vegetation throughout Watford during the summer is very likely to produce them; they are common in town centre gardens and occasionally come to M.V. Adults overwinter among leaf litter or vegetation (within beech nuts has been quoted, Majerus and Kearns). We have yet to find them under bark or among vegetation around logs, material we frequently sample during the winter and among which we often find other coccinellid species. Development follows the typical ladybird cycle with eggs laid in the spring and larvae developing according to temperature and food (aphid) availability.

Variation in pattern and colour is considerable although there are three main forms all of which occur commonly:
Decempunctata is probably commonest, with a red, orange or brown ground colour and between 0 and 12 distinct dark elytral spots, although rarely more spots have been recorded.
Decempustulata has a dark grid like pattern overlaying the red, orange, yellow or brown ground colour. The strength and width of the pattern varies.
Bimaculata is a melanic form with broad transverse subhumeral marks of red or yellow, obscure in immature specimens. Ground colour varies from black to red-brown.
Forms intermediate beween these do occur but rarely.

3.5-5mm. Glabrous. Body form almost round (A. bipunctata), with a short transverse elytral ridge subapically (Harmonia axyridis). Legs and antennae brown or orange, extremities darker. Underside of abdomen yellow or orange, mesosternal epimera light; yellow, orange or light brown (A.bipunctata). Upper surface markings, including pronotum, very variable, as above.

Description from 10 Watford specimens at X10