This can most often be achieved (except in 'new' individuals) by
comparing leg colour (2-spot always all black; 10-spot pale and brown, often
wholly) or by the pattern on the forebody (pronotum): in the 2-spot this is
black with white patches down both sides: with darker bodied forms, the white
patches shrink and in melanic forms the pronotum is all black. In the
10-spot, the pronotum is predominantly white with spotty black markings; as the
ladybird darkens the black patches enlarged but the pattern still contains
multiple white patches; even in the melanic forms, there is usually a white rim
down the pronotal side.
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The most common form of the 2-spot ladybird, the typica,
has two black spots on a red or orange elytral
(wing-case) background.
The pronotum (forebody) is black with white edges. |
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Two-spot ladybird Adalia
bipunctata
This, the most abundant species in towns, is also the
most variable. Furthermore, the various pattern forms may
be more or less frequently encountered in different parts
of the country (or even across London). The most common
variant is the quadrimaculata melanic (left:
male mating with a 'typical' female) although melanics
with two or six spots are not rare. It is possible to
consider one genetic series of variants as running from
an all black pattern to an all red one (neither extreme
has been found in Britain). Continues ....... |
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Two-spot ladybird (continued)
The typica form (see main page) and the quadripustulatus
(black with four red marks: above left) are towards
either end of a scale of variation which proceeds from a
type with extra small, satellite spots to the weak annulata
form ('extended spot', left) through barred patterns
(intermediate and strong annulata: drawing
right) to types which are predominantly black with red
patterns such as the duodecempustulata with
twelve red patches. There are intermediate
patterns such as that to the above right
with ten red spots (decempustulata?). |
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Small satellite spots are seen on either side of the large spot. As
these enlarge the satellites join up with the central spot to give the
'enlarged spot' or 'weak annulata' form. |
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The annulate series continues with the extension of the mark
across the elytra ('bar annulata') and doubling of this bar
('intermediate annulata'). The white on the pronotum is reduced
to a small rim as the amount of black increases on the elytra. |
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Blackening occurs along the midline (suture) and tip of the elytra:
'strong annulata'. |
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The black areas can become predominant giving a black
ladybird with a few red spots. This sexpustulata form
is quite common.
Note that the white margins of the pronotum have
disappeared. |
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The red spots can be eliminated - from the rear. The
four-spotted, quadripustulata, form is the most
common melanic variant. |
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There is an all black form of the 2-spot but this has
not been recorded in the British Isles. Another interesting variant is
the purpurea form (right, found by Diane Andrews in Alexandra
Park). |
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Some variations are due to genes other than the annulate set.
The 'rabbit's ears' pattern (©
Colin Duke) is, to quote Mike Majerus: a heterozygote between typica
and one of the simulatrix forms, with a modifier allele at another locus
having an effect on the black patterning. It is very rare.
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Adalia decempunctata
(10-spot ladybird) |
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10-spot ladybird Adalia
decempunctata
This has melanic forms (most commonly with two red
spots on a black background, left) but probably the most
common variant is the decempustulata, chequered
form (right). 10-spots are very slow to develop their red
colouration so are commonly seen with yellow or orange
markings. In contrast to the 2-spot ladybird, variations
of this species seem to be constant geographically. Continues .... |
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Ten-spot ladybird (continued)
The species may have between 0 and 14 spots (with the
most spotty specimens, a scutellar spot also develops so
some have 11 or 15 spots in total). The pronotal (forebody)
pattern is usually quite distinctive, mainly white with
small black spots but the amount of black increases . The ladybird is paler than most other
red species being palest, often creamy, around the rim as here:
six-spotted (left) and fourteen-spotted (right). Note the largely
white pronotum and 'creamy' rim of the hindbody. |
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It is quite rare (in my experience at least) to find
10-spot ladybirds with ten spots. They commonly have as
few as four or six (left).
Its pronotum (forebody) is predominantly white with a
distinctive pattern of black dots.
Its legs and underside are predominantly pale or brown. |
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This individual has ten elytral spots but it also has
a scutellar spot (at the middle of the front of the
hindbody) making it eleven-spotted! Spots can vary in
size - some being quite large. The pronotal pattern is
distinctive. |
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Spot number can increase and fusion occur. Note that
the black areas on the pronotum are also extending. |
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The common melanic form of the 10-spot has a forward,
curved red patch on each elytron. There are no white
marks on the pronotum of this specimen although these often persist in
melanic individuals. |
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Some pale areas persist under the body and, sometimes, on the legs. |
However, there is no simple progression from all-red to all-black as with the
2-spot ladybird annulate series. Other gene sets have considerable effect on
patterns. The books by Majerus, Hodek and Klausnitzer & Klausnitzer
illustrate various variations and delve into the genetics. (books)