Thursday, May 27, 2004

An attempt at a higher-level phylogeny of the ants appeared in the most recent Molecular Phylogenetics and Evolution:

Astruc, C., J. F. Julien, C. Errard and A. Lenoir. 2004. Phylogeny of ants (Formicidae) based on morphology and DNA sequence data. Molecular Phylogenetics and Evolution 31:880-893.

In order to reconstruct ants' phylogeny, we analysed DNA sequences for two nuclear genes, abdominal-A and Ultrabithorax, from 49 species of ants and two outgroups. As these genes control the development of the first segments of the abdomen in insects, which are very variable in ants (petiole, postpetiole, and gaster constriction), we hypothesized that the morphological variations between the subfamilies may be correlated with mutations of some abd-A or Ubx regions. Contrarily to our hypothesis, these sequences are highly conserved. The differences observed concern mainly third codon positions and present some saturation. Phylogenetic reconstructions were carried out using the genetic raw sequence data and by combining them with a set of morphological data (Total Evidence). Relations among subfamilies of ants remains poorly resolved with molecular data only, but adding these data to morphological characters confirms and reinforce the topology of Baroni Urbani et al. (1992): a Poneroid complex [Ponerinae, Cerapachyinae, Leptanillinae and army ants], a Formicoid complex [Dolichoderinae, Formicinae] and a Myrmecoid complex [Myrmicinae, Myrmeciinae, Pseudomyrmecinae, Nothomyrmeciinae]. Our molecular results allow resolution near the branch tips and three subfamilies (Dolichoderinae, Formicinae and Pseudomyrmecinae) always appear as monophyletic. The Formicinae and the Dolichoderinae have close relationships. The Camponotini appear as a strong clade inside the Formicinae. The Ponerinae are separated in two parts: the Ectatommini and all other tribes. The Cerapachyinae, Dorylinae, and Ecitoninae belong to the same clade, the Cerapachyinae being confirmed in their subfamily status. The Myrmicinae appears to be very heterogeneous, with the Attini forming a very stable and well-separated group.

There is, to be honest, less here than meets the eye. Astruc et al give a valient effort at a thorough taxon sampling but the genes they employed- Abd-A and Ubx- do not give much signal at the more interesting deeper levels. The resolution in the combined morphological and molecular analysis seems to be driven largely by morphology, and the results consequently provide little new insight into deep ant history. However, the question of formicid phylogeny remains an interesting one, and as new genes become available for phylogenetic analysis we should expect some real progress on this front in the not-too-distant future.

I say hello and welcom to Mr. Myrmecos :)) - Thanks for joining this blog. It looks as if you are well doing by using the blogging possibilities!
Additionally, I want to use this space to notify our readers that from now on there will be a possibility for outstanders in giving comments on the articles and news posted here.

Wednesday, May 26, 2004

Since I'm new on the Ant News Blog, I'm playing around with the blogging possibilities. I thought I'd share this photograph from of a parasitic Polyergus slave-raiding ant being carried by a Formica argentea slave ant. When I disturbed this colony a few weeks ago up in the high Sierra of California, most of the host Formica scattered for cover, while most of the Polyergus clinging to the underside of the nest rock stayed put until their hosts returned, one by one, to carry the parasites back down into the nests.

Surprise, surprise. Yet another tropical story where ants form a crucial link.:

Saporito RA, Garraffo HM, Donnelly MA, Edwards AL, Longino JT, Daly JW.
2004. Formicine ants: An arthropod source for the pumiliotoxin alkaloids of dendrobatid poison frogs. Proc Natl Acad Sci U S A. 101(21):8045-8050.

ABSTRACT. A remarkable diversity of bioactive lipophilic alkaloids is present in the skin of poison frogs and toads worldwide. Originally discovered in neotropical dendrobatid frogs, these alkaloids are now known from mantellid frogs of Madagascar, certain myobatrachid frogs of Australia, and certain bufonid toads of South America. Presumably serving as a passive chemical defense, these alkaloids appear to be sequestered from a variety of alkaloid-containing arthropods. The pumiliotoxins represent a major, widespread, group of alkaloids that are found in virtually all anurans that are chemically defended by the presence of lipophilic alkaloids. Identifying an arthropod source for these alkaloids has been a considerable challenge for chemical ecologists. However, an extensive collection of neotropical forest arthropods has now revealed a putative arthropod source of the pumiliotoxins. Here we report on the presence of pumiliotoxins in formicine ants of the genera Brachymyrmex and Paratrechina, as well as the presence of these ants in the stomach contents of the microsympatric pumiliotoxin-containing dendrobatid frog, Dendrobates pumilio. These pumiliotoxins are major alkaloids in D. pumilio, and Brachymyrmex and Paratrechina ants now represent the only known dietary sources of these toxic alkaloids. These findings further support the significance of ant-specialization and alkaloid sequestration in the evolution of bright warning coloration in poison frogs and toads.

UPDATE: I see that Cristoph has already blogged on this one below. Crud. I'm only three weeks behind.

RESPONSE - Pattern, process, and the size-grain hypothesis - Ecol Entomol, Vol 29, Issue 3, pp. 381-382 (Abstract)

COMMENT - The size-grain hypothesis in ants: conflicting evidence or confounded perspective? - Ecol Entomol, Vol 29, Issue 3, pp. 380-380 (Abstract)

Guards and thieves: antagonistic interactions between two ant species coexisting on the same ant-plant - Ecol Entomol, Vol 29, Issue 3, pp. 345-352 (Abstract): "Acacia mayana , its ant-guard Pseudomyrmex ferrugineus, and an apparent opportunist parasite of the mutualism, the generalist ant Camponotus planatus..."

Friday, May 21, 2004

Emergency queen rearing in honeybee colonies with brood of known age

Pollen consumption in honey bee larvae: a step forward in the risk assessment of transgenic plants

Non-lethal sampling of honey bee, Apis mellifera, DNA using wing tips

Tuesday, May 11, 2004

Eight highly polymorphic microsatellite markers for the army ant Eciton burchellii - Mol Ecol Notes, Vol 4, Issue 2, pp. 234-236 (Abstract)

Polymorphic microsatellite loci in Allodapine bees for investigating the evolution of social behaviour - Mol Ecol Notes, Vol 4, Issue 2, pp. 303-305 (Abstract)

Characterization of microsatellite loci in red wood ants Formica (s. str.) spp. and the related genus Polyergus - Mol Ecol Notes, Vol 4, Issue 2, pp. 200-203 (Abstract)

Monday, May 10, 2004 | Ameisen
Ant-Special in german language in the Online-Magazine "Geoscience" (Springer publishers; no english translation), rubric "Fokus/Biologie".

Polyandry and fitness in the western harvester ant, Pogonomyrmex occidentalis - Mol Ecol, Vol 13, Issue 6, pp. 1601-1606 (Abstract) Detailed view on the sociogenetics of single P. occidentalis nests: these western harvester ants have multiple mated queens. Moreover, the results of Wiernasz et al. again are an indication in this species for a fitness benefit for multi-colored colonies: those which had a rich spectrum of genetic patrilines accumulated (and therefore a low relatedness among nest members) were the fastest growing colonies.

Thursday, May 06, 2004

Saporito et al., 10.1073/pnas.0402365101: Report on the weird finding that the toxic bioactive lipophilic alkaloids ( "pumilotoxins") of poison frogs (Dendrobates pumilio) seem to be amassed via consumption of ant of the genera Brachymyrmex and Paratrechina (Formicinae), as these were found in the stomachs of these frogs. They write that "these pumiliotoxins are major alkaloids in D. pumilio, and Brachymyrmex and Paratrechina ants now represent the only known dietary sources of these toxic alkaloids. These findings further support the significance of ant-specialization and alkaloid sequestration in the evolution of bright warning coloration in poison frogs and toads."