David Element's Wildlife Web Page Beetles 7

David Element

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_____________________ Beetles 7 - Ladybirds 2

TWO-SPOT LADYBIRD Adalia bipunctata (TYPICAL)

TWO-SPOT LADYBIRD Adalia bipunctata (LARGE SPOTTED, BANDED)

TWO-SPOT LADYBIRD Adalia bipunctata (FOUR-SPOTTED MELANIC)

TEN-SPOT LADYBIRD Adalia decempunctata (TYPICAL)

TEN-SPOT LADYBIRD Adalia decempunctata (CHEQUERED FORM)

These illustrations do not show a full range of the genetically inherited colour forms of these very variable species, merely a selection. Some forms have been named, but they tend to merge into one another, so these definitions are really rather artificial. It is likely that the darker forms may gain a slight advantage early in the year when they emerge from hibernation as they should warm up more quickly in weak sunlight, but whether this has ever been scientifically proven is another matter - and the tolerance of cold weather may have more to do with the naturally occurring glycols in the haemolymph (blood). Certainly the different colour forms seem to mate with each other without any obvious preferences and the apparent spot-pattern overlap between the species doesn't seem to confuse them as they presumably mate in response to pheromonal signals rather than spot numbers. Students of ladybird genetics will find a great deal to delight them in Dr. Michael Majerus' superb 'LADYBIRDS', NEW NATURALIST, HARPERCOLLINS, 1994. ISBN 000 219934 3 (HARDBACK); ISBN 000 219935 1 (PAPERBACK) which is now out of print and attracting high prices on the second hand book market (particularly the hardback which is highly collectable). Quite apart from the pattern variations, the colours may alter with the age of the insect, as will be evident from the final three photographs of the Ten-spot Ladybird (chequered form). Very fresh adults appear to be creamy white and then as the pattern develops the background shade turns to pink (although this may be the colour of the spots in melanic forms).

Fully melanic Ten-spots have not been included here. The faintly spotted typical form Ten-spot ladybird (first picture) appears to have some sort of fungal infection on the top of its head. Two-spot, Ten-spot and Pine Ladybirds often associate together on tree trunks, frequently close to scale insects, and the melanic forms in particular may be hard to identify.

The number of spots alluded to in the common names may be thoroughly misleading and beginners should not feel any embarrassment if they are confused by these classifications! After all there are only another 45 British ladybird species (and only 23 big ones) once these two have been cracked...

Even the scientific names of ladybirds often get the number of spots wrong in the variably marked examples - and students of Latin may notice some spelling corruptions which have perpetuated since the original names were allocated. The use of the suffixes 'punctata', 'guttata', 'maculatus' and 'pustulatus' all mean much the same thing, and once 'punctata' had been used for a species with a given number of spots another suffix would have been employed for a more recently named species with a similar number of spot-like markings.