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Posts Tagged ‘biology’

Primitive ant people…

…are at it again:

The twilight zone:
ambient light levels trigger activity in primitive ants

What’s unfortunate about this title is that the judgement “primitive” has nothing to do with the research. It is unnecessary. The study is about how one species of ant uses ambient light levels to trigger foraging.  It’s a nicely done bit of work.  But whether or not these ants are “primitive” has zilch to do with the science.

Back in the day, western anthropologists would study Primitive Culture. Such terms are no longer used in that field, and for good reason. It’s not just that labeling other humans as “savages” and “primitives” is offensive.  It’s that these laden terms carry more baggage than information. “Primitive” leads us to assume we know things about the subject that were not, in fact, ever quantitatively measured or tested. In doing so we unknowingly substitute prejudice for knowledge.

In this sense, many myrmecologists remain stuck in the Victorian mindset, viewing ant societies through a thick glass of presumption. “Primitive” serves no objective function here- all I learn from its inclusion in the title is that the authors don’t fully grasp the evolutionary process.

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Do any of you know what this little animal might be?  I honestly have no idea, and rather than look it up I thought I’d crowd-source it to you folks first.

It was lurking on the underside of a leaf at the Archbold Biological Station in Florida along the shores of a sinkhole lake.  This was back in June.  It’s about a centimeter long.

update: It’s a hover fly larva.  Ted MacRae picked it- thanks!

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asf

Pogonomyrmex maricopa (at left) tussles with an Aphaenogaster albisetosa at the Aphaenogaster nest entrance.

While in Arizona, I chanced upon a set of ant fights that I’d observed several times previously.  Single workers of the maricopa harvester ant Pogonomyrmex maricopa would approach a nest of their competitor, Aphaenogaster long-legged ants, and spend a few minutes drawing heat from the guards before wandering off.

ag

Same thing, but different individuals (note differences in limb wounds from the previous photo)

The interaction is common enough that it really couldn’t be just a chance encounter.  Are the Pogos doing this for a reason?  Are they distracting the Aphaenogaster from foraging?  And, are there any myrmecology students in Arizona who need a little research project? It’d be great to figure out the purpose of the fights.

ag

Three on one. Do the Pogos subject themselves to this treatment as a decoy, to draw Aphaenogaster away from shared foraging territory?

photo details (all photos): Canon mp-e 65mm 1-5x macro lens on a Canon EOS 50D
ISO 100, f/13, 1/250 sec, twin flash diffused through tracing paper

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Here’s an image for the textbooks:

gracilis2Ants, like butterflies, pass through egg, larva, and pupa phases on their way to adulthood. While in Florida earlier in this summer I found a nest of the twig ant Pseudomyrmex gracilis with brood present in all stages, providing the material to make these images.

The key was placing the developing ants on a glass slide.  This provided distance between them and the cardboard background, so that the backdrop is blurred while the insects remain in sharp focus.  These images are not what I’d call fine art, but I’m happy with them as solid illustrations of ant biology.

gracilis3

photo details (both photos): Canon mp-e 65mm 1-5x macro lens on a Canon EOS 50D
ISO 100, f/11, 1/160 sec, twin flash diffused through tracing paper

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One of the most vociferous debates in taxonomy is over a catchy-sounding concept called DNA barcoding.  Since nearly all organisms carry a version of the COI gene in the mitochondrion, the idea is that the DNA sequence of the gene can serve as a standard identification marker.  A barcode, of sorts.  Of course, the practice only works if species have unique COI sequences.  Which they do, much of the time, and the barcoders consequently have been successful in garnering research money and churning out publications.

So what’s the problem? (more…)

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wilson1Who is supposed to read The Superorganism?

I can’t really tell.  While I’m enjoying Holldobler & Wilson’s latest tome, I am perplexed at the book’s target audience.  The text switches between broadly anthropomorphic prose clearly aimed for a general audience and obtuse jargon digestible only by the experienced biologist.

I get the feeling that the authors- at least one of them, anyway- desired a technical book more along the lines of Bourke & Franks, while the marketing department at Harvard University Press wished to trade on the authors’ name recognition with a glossy coffee-table production.  The tug-of-war behind the scenes must have been impressive, and the effect is surreal.  It’s a bit like hanging your automobile’s operating manual in a gilded frame over the mantle.  The result is not unpleasant, mind you, but I can’t help to think the authors missed an opportunity to produce either a comprehensive professional review or an engaging popular work instead of compromising in the middle.

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cephalotes24

A trail of Atta leafcutting ants in Gamboa, Panama.

From the recent literature:

The Journal of Experimental Biology has a lab study by Dussutour et al documenting how leafcutter ants avoid traffic jams under crowded trail conditions.  Apparently, unladen ants increase a narrow trail’s efficiency by following the leaf-carrying ants instead of trying to pass their slower sisters. See also commentary by JEB and Wired.

source: Dussutour, A., Beshers, S., Deneubourg, J. L., Fourcassie, V. 2009. Priority rules govern the organization of traffic on foraging trails under crowding conditions in the leaf-cutting ant Atta colombica. J Exp Biol 2009 212: 499-505.

In the journal PLoS One, Youngsteadt et al document that the seeds of the neotropical ant plant Peperomia macrostachya are dispersed by just a single species of Camponotus in spite of a high ant diversity at the study site.

source: Youngsteadt E, Baca JA, Osborne J, Schal C, 2009. Species-Specific Seed Dispersal in an Obligate Ant-Plant Mutualism. PLoS ONE 4(2): e4335. doi:10.1371/journal.pone.0004335

A smattering of ant taxonomic papers in the online journal Zootaxa includes work on Lordomyrma by Bob Taylor, Pheidole by Jack Longino, and the Egyptian Solenopsis by Mostafa Sharaf et al.

source: Zootaxa Hymenoptera

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