Sunday 25 August 2013

Astata tropicalis, Arnold, 1924

I won't go into great lengths about the difficulties in identifying African insects that are neither Mediterranean nor South African. Instead I will open with a picture.

Astata tropicalis, Chongwe, Lusaka, Zambia

First off, let me say that this stout, fuzzy, big-eyed little character is a male bee-wolf. Bee wolf is always a bit of an odd name, as the insects described are neither wolves nor bees, but rather a group of 'wasps' that prey upon specific genera or species of bee.

In this particular case, which I have convinced myself is a male of Astata tropicalis, the name 'Bee-Wolf' is a bit of a misnomer, as the prey are usually spider hunting wasps (of the Pompiliidae, quite possibly the most attractive bunch of insects to leave me at a complete loss where identification is concerned). The term 'Digger wasp' or 'Sphecoid' is also employed occasionally, but I would typically use 'Digger wasp' for the Sphecidae, and 'Sphecoid' refers to a superfamily (Sphecoidea) which doesn't exist any more, as it has been merged with the bees in the Apoidea (largely because the various wasps of the Sphecoidea were in many cases more closely related to bees than to one another).

Some entomologists employ the clades 'Spheciformes' and 'Anthophila' to keep track of what in the Apoidea is and isn't a bee, but this merely repeats the problems seen in the two superfamilies - the only real distinction between the bees, in the monophyletic (=phylogenetically valid) Anthophila and the paraphyletic (=phylogenetically beyond Iffy and into the great beyond of phylogenetically useless, like the words 'Fish' and 'Invertebrate') Spheciformes is that the Anthophila are herbivorous.

To put this into context, it's like treating pandas on their own as a clade equivalent to the seals, bears, dogs, cats, raccoons and weasels, on the basis that Pandas are (mostly) herbivorous, despite them clearly being bears.

Fortunately, there is a solution: we can call it a Crabronid. Until Crabronidae becomes a superfamily, which, seeing as the Anthophila are in fact nested within it, and then we'll probably call it an Astatid (=member of the theoretically soon-to-be-defined family Astatidae)

Now that we've brought back the long lost pre-amble, let's have a gander at the phylogeny:

I've already disclosed that I believe - reasonably firmly, hence no cf, that this is

Astata tropicalis 
Arnold, 1924

which belongs to the: 

- Astatinae
- Crabronidae
(skipping over the popular but meaningless 'Spheciformes') - Apoidea           
- Aculeata             
- Apocrita                 
- Hymenoptera             
- Hymenopterida             
- Endopterygota                 
- Eumetabola                         
- Neoptera                                  
- Metapterygota                              
- Pterygota                                           
- Dicondylia                                              
- Insecta                                                        
- Hexapoda                                                        
- Arthropoda                                                         
- Ecdysozoa                                                              
- Protostomia                                                               
- Bilateralia                                                                     
- Eumetazoa                                                                       
- Animalia                                                                              
- Eukaryota                                                                                 


And, beyond heading into a rather iffy breakdown of the relationships between life and near-life, and then organic molecules, chemicals generally and eventually just plain old matter, that's all, folks.



 

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