Current Biology has just published what is surely among the most significant papers this year on insect evolutionary relationships:
The importance of the paper derives from a combination of hitting a controversial topic with a much-needed phylogeny, and doing so with a staggering amount of information. The 300 or so genes employed to create the genomic tree is orders of magnitude more data than that used in any previous effort, and the result finally brings clarity to a question that’s been nagging a lot of Hymenopterists: what are the closest relatives of ants?
Probably, bees and spheciform wasps.
That’s not necessarily the relationship I would have guessed, but it holds under multiple modes of analysis.
Here’s the abstract (emphasis mine):
Eusocial behavior has arisen in few animal groups, most notably in the aculeate Hymenoptera, a clade comprising ants, bees, and stinging wasps. Phylogeny is crucial to understanding the evolution of the salient features of these insects, including eusociality. Yet the phylogenetic relationships among the major lineages of aculeate Hymenoptera remain contentious. We address this problem here by generating and analyzing genomic data for a representative series of taxa. We obtain a single well-resolved and strongly supported tree, robust to multiple methods of phylogenetic inference. Apoidea (spheciform wasps and bees) and ants are sister groups, a novel finding that contradicts earlier views that ants are closer to ectoparasitoid wasps. Vespid wasps (paper wasps, yellow jackets, and relatives) are sister to all other aculeates except chrysidoids. Thus, all eusocial species of Hymenoptera are contained within two major groups, characterized by transport of larval provisions and nest construction, likely prerequisites for the evolution of eusociality. These two lineages are interpolated among three other clades of wasps whose species are predominantly ectoparasitoids on concealed hosts, the inferred ancestral condition for aculeates. This phylogeny provides a new framework for exploring the evolution of nesting, feeding, and social behavior within the stinging Hymenoptera.
Source: Brian R. Johnson, Marek L. Borowiec, Joanna C. Chiu, Ernest K. Lee, Joel Atallah, Philip S. Ward (2013) Phylogenomics Resolves Evolutionary Relationships among Ants, Bees, and Wasps. Current Biology, Available online 3 October 2013. http://dx.doi.org/10.1016/j.cub.2013.08.050
That IS interesting – but I must confess to being a little sad that the morphological cladistics that has been so carefully (or not so carefully in light of these results) conducted over those years seems so useless… if the phylogeny in this study turns out to be correct that is. But seeing how stupendously big their data set seem to be, its not likely that the results are wrong is it?
Will be interesting to see how the families group onto this “superfamily” level tree, and a similar approach to the whole of apocrita… now that would be something.
I too am surprised at this finding. So what of the morphological and fossil evidence that ants are related to wasps? I recall a famous amber specimen of what is thought to be a transitional form between ants and tiphiid wasps.
Thanks for your comment, Marcoli. The Wasp/Ant connection still holds, as bees themselves are just another kind of wasp, anyway. The tiphiid connection turned out to be a bit of red herring. I suspect taxonomists were led astray by the convergent resemblance of some tiphiids with ants. See Methoca, for example: http://cedarcreek.umn.edu/insects/album/025053021ap.html
Now I’m going to have to read the whole thing to figure out what the cuckoo wasps were doing before they had anything to . . . cuckoo?
Also, I’m not sure if cuckoo’s a verb, and that word never looks right when I type it.
The Chrysidioidea are mostly comprised of ectoparasitoids, wasps that paralyze other insects, hide them (if they arent hidden already) and oviposit on them – the cuckoes have simply removed the “hide” part, and now place their eggs in the cells of solitary hymenoptera, which are by default already well housed.
So I discovered! I only knew of Cuckoo wasps as the wasps that were cleptoparasites of other wasps and bees (and occasionally walking sticks).
I saw ‘Chrysidoidea’ and ‘Cuckoo wasps’ and my dyslexic brain saw ‘Chrysidinae, the Cuckoo wasps’ 🙂
I still figured that we just had a lot of wasp-on-wasp action and/or some very, very frustrated walking sticks and figured it was a more specialized early branch-off, but now I see where it was going. 🙂
Also, wow, even the Chrysidinae are WAY more diverse in their hosts than I thought. Everywhere you look you find more awesomeness.
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Is there an easy way to tell a Spheciform wasp from a tiphioid-pompilioid wasp? Considering that they all do similar things…
Bees and spheciforms have a distinctly rounded shape to the corners of the pronotum, like so:
http://www.entomology.umn.edu/museum/links/coursefiles/JPEG%20images/Hymenoptera%20web%20jpeg/pronotum-1.jpg
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It’s difficult to find well-informed people about this subject,
however, you seem like you know what you’re talking about!
Thanks