I wellcome your recomendation. These species were collected in Haut Ogooué province, with specific time and place I've just transmitted to Oldrich Nedved.
I would recomend to ask Helmut Fürsch. He is specialised in Coccinellidae worldwide. I don't know, whether he can make the determination allone with the pictures, but you can try it, if you have more information about date, place, environment and so on.
If you want to try this, I can give you his email-adress.
I agree with Stephen, (D) is a cucurbita phytophagus, with similar habits as Epilachna varivestis on mexican bean, or E. borealis, or E. chrysomelina, or E. vigintioctopunctata, on their own hosts and world distribution.
Finally I've discoverd that the D is Henosepilachna reticulata reticulata, a phytophagous species grating cucurbit leaves. B and C still waiting their nomanclature.
B: Scymnus thiollierei Mulsant or Scymnus (Pullus) subvillosus-group; sure determination only genital; Sc. subvillosus is not african, but widespread in pest control
C: Probably Coccinella transversoguttata F. or also possible the pakistan species Coccinella marussii Kapur; sure diagnosis only genital or real inspection.
D For sure Henosepilachna reticulata reticulata (Olivier)
This is the determination of Prof. Dr. Helmut Fürsch from Germany, he is one of the best connoisseurs of Coccinellidae worldwide.
Let me first be clear, I don’t want to measure me with professor Fursch. I’m absolutely no match for him as my knowledge about my favourite, the ladybirds, is reaching barely his ankles.
But I have some problems with the C-determination. Nor Coccinella transversoguttata Fabricius, 1781 or Coccinella marussii Kapur, 1973 (also belonging to the C. transversoguttata–group) seem, at least for me, matching with the species shown on the picture.
Moreover, if I look to the pictures the ladybirds give the impression to have hairs on their elytra and pronotum (in this case covered with glue or some other artificial fluid?). Does this mean this is a member of the Epilachninae subfamily? Or is it a fairly small ladybird (we do not have the size) and are we into some other subfamily? But again patterns and colours….?