Ladybird in the sun

Hippodamia sp. Ladybird beetle
Tucson, Arizona

Photo details: Canon 100mm f2.8 macro lens on a Canon EOS 20D
ISO 100, f4.5, 1/320 sec, ambient light

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Friday Beetle Blogging: Dynastes granti, the Western Hercules Beetle

A male western hercules beetle, Arizona.

Meet Dynastes granti. This behemouth of an insect is North America’s heaviest scarab beetle, found in the mountains of the American southwest where adults feed on the sap of ash trees. I photographed these spectacular insects a few years ago while living in Tucson.

The impressive pronotal horn on the beetle pictured above indicates a male; females are considerably more modest in their armaments:

Male and female hercules beetles

As is so often the case in animals, males use their horns to fight each other for access to females, attempting to pry their opponents off the branches.  Size is important, and it varies notably among individuals depending on how well they fed as developing larvae:

Size variation among male hercules beetles. My money is on the guy on the right.

The three beetles pictured here lived in our house for a while as pets; they were good-natured insects and would sit happily on our fingers eating maple syrup.

Photo details: Canon 100mm f2.8 macro lens on a Canon EOS 20D.
ISO 400, f3.0-f5.0, 1/50-1/125 sec, ambient light at dusk

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Friday Beetle Blogging: Trox Hide Beetle

Trox - Hide Beetle - Arizona, USA

Scarab’s shrewd cousin,
Elytra warty like hide.
Must be Trogidae!

Photo details: Canon 100mm f2.8 macro lens on a Canon EOS 20D
ISO 100, f/16, 1/250 sec, indirect strobe in white box

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A battle for the desert

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.

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.

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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Filming Ants in Arizona

Swooping from the top of a saguaro down to the desert floor: Howard Bourne swings the crane while Martin Dohrn drives the camera. Tucson Mountain Park.

What was I doing in Arizona last month?

Thanks for asking.  I was helping a film crew wrangle harvester ants for an upcoming National Geographic documentary.  The crew, an all-star cast of nature cinematographers including Martin Dohrn, Howard Bourne, and Gavin Thurston, is still in the field- you can follow their progress by blog. The program is tentatively titled “Planet of the Ants” and should be on television in 2010.

If there’s one thing I learned from the experience, it is that nature films are strenuous work.  A night with more than 5 hours’ sleep was unusual.  We’d often film well past midnight, only to be up before dawn to catch the early morning foragers at another site.  The equipment occupies 20 heavy cases and is constant need of being loaded, unloaded, or carried about here and there.  The hotter the temperature (and we saw temps in Tucson above 108º), it seems the farther and more frequently the gear needed to be ferried about.

But no matter.  The shoot was tremendous fun, and I could not imagine a more genial lot than Martin, Howard, and Gavin.  Below is a photo essay from the week.

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Friday Beetle Blogging: Leconte’s Jewel Scarab

Chrysina lecontei, Arizona.

Jewel scarabs emerge during Arizona’s summer monsoon, and collectors from around the world descend on the region with their blacklights and mercury vapor lamps to attract the beetles. Chrysina lecontei is the smallest and rarest of the three Arizona species.

Chrysina leconte, Arizona.

photo details (both photos): Canon 100mm f2.8 macro lens on a Canon EOS 20D
ISO 100, 1/250 sec, f/18, indirect strobe in white box

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Just hanging out…

Tenodera aridifolia, Arizona.

photo details: Canon 100mm f2.8 macro lens on a Canon EOS 20D
ISO 100, 1/250 sec, f/14, indirect strobe in a white box

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Ant Research Roundup (5.ii.08)

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.

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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

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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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Dreaming of the desert

It’s 6ºF (-14ºC) here in central Illinois.  Can’t do much about that, but here are some shots of warmer times and warmer places.

Monument Valley, 2006

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Friday Beetle Blogging: Spider Beetle

Gibbium sp. Spider Beetle, Arizona

Spider beetles are not predators like their namesakes but are instead pests of stored grain.  I was surprised at how difficult they were to photograph.  Their round bodies were hard to fit into a single focal plane, while their reflective elytra were prone to harsh glare.  I could not do much about the first problem, but the lighting was solved by placing the beetle inside a white box and firing an off-camera strobe into the box but away from the beetle.

Gibbium sp., Arizona

photo details (both images): Canon MP-E 65mm 1-5x macro lens on a Canon EOS 20D
ISO 100, 1/250 sec, f/13, indirect strobe fired into white box

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