An African example of so-called muellerian mimicry
(writing in progress)
Here is a West African example of a so-called ‘Muellerian mimicry ring’.
The similarity in pattern is impressive because these five spp. of butterfly are not closely related: there are two different families included (Papilionidae and Nymphalidae), within one of the families there are three different subfamilies included (Nymphalidae: Nymphalinae, Satyrinae, and Acraeinae), and the two spp. within one of these subfamilies belong to different genera (Acraeinae: Bematistes and Acraea).
Were all the members to belong to the same genus, or same subfamily, it would be easier to dismiss this as merely an example of the extreme speciosity of tropical organisms. Instead, there is clearly some sort of convergent evolution here, not so?
Now, the conventional view of this ‘Muellerian mimicry ring’ is that the Acraeinae have served as ‘models’ and the other three spp. are their ‘mimics’. But why is that a logical interpretation? And even if it’s true that the pattern shown here is more typical of Acraeines than of the other subfamilies (in the sense of being rather consistent within that subfamily, occurring also in other spp. elsewhere), who’s to say that any deception (intrinsic to the definition of mimicry) is occurring?
To give you an idea of the relationships of these butterflies relative to what you know in the Cape Town area:
You can see Acraea on Kiggelaria africana in Cape Town and it looks similar to its two relatives below.
Nymphalines are the common ‘pretty but not sinister’ butterflies everyone likes to see, which usually look inconspicuous when perched but flash pretty colours when they fly. The species below is a departure from that pattern, convincingly aberrant.
Satyrines are the ‘browns’, which tend to dwell in grasslands (plenty of spp. on the Highveld and in the mountains near Cape Town), and tend not to be particularly gaudy although often decorated with eyespots. The species below is pretty aberrant as satyrines go.
The final sp. below is congeneric with the familiar Christmas butterfly (Papilio demodocus) in Cape Town, which is probably also common on your family farm in the Cederberg because its caterpillar eats Citrus. If you can visualise the Cape Town butterfly with its spotted pattern, you’ll know that the pattern below is pretty aberrant for a papilionid although the large wings and the hindwing shape do give the game away a bit.
I certainly accept that there’s something to be explained here. However, assuming that all these spp. are noxious, how can one call it a case of ‘mimicry’?
If it’ is ‘mimicry’, that means someone is pretending to be someone else. True, the pattern may be typically acraeine, but unless the other spp. are less noxious than the acraeines, and unless the acraeines greatly outnumber the other 3 spp. in the shared habitats, what logical basis is there for calling this ‘Muellerian mimicry’?
Bematistes epaea (Nymphalidae: Acraeinae):
http://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Acraea_epaea.JPG/220px-Acraea_epaea.JPG
Acraea jodutta (Nymphalidae: Acraeinae):
http://b03.deliver.odai.yale.edu/e9/11/e9117d05-1257-46cc-8b4a-7445bc3ed3c2/814997-sm.jpg
Pseudacraea erytus (Nymphalidae: Nymphalinae):
http://upload.wikimedia.org/wikipedia/commons/9/9c/Pseudacraea_eurytus.JPG
Elymnias bammakoo (Nymphalidae: Satyrinae):
http://www.discoverlife.org/IM/I_DJL/0002/320/Elymnias_bammakoo,_female,_top,I_DJL233.jpg
Papilio cynorta (Papilionidae):
http://en.butterflycorner.net/fileadmin/processed/csm_Papilio_cynorta_f_04_o_NHM_01_620f9f94b6.jpg
(writing in progress)
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