Ants

New (and final?) Notes from Underground

The latest edition of the myrmecological newsletter is online here. It may well be the last, according to editor Gordon Snelling:

We have close to 200 members and I can count on two hands the people that have regularly supported Notes by sending in material for publication… I feel like I am banging my head on a wall at times and honestly I am losing the motivation to keep this going.

Notes from Underground has come and gone before. The printed newsletter was inaugurated in 1988 by Harvard University’s Norm Carlin, Stefan Cover, and Mark Moffett, and served for five years as an active and much-appreciated conduit for field anecdotes, cartoons, taxonomic rants, and calls for specimens. When Harvard’s social insect group evaporated in the early 1990’s, Notes from Underground went with it.

The internet would seem to offer a better medium for a newsletter like Notes, and 2003 Notes from Underground was reincarnated. Editorship and inspiration passed to Army Ant specialist Gordon Snelling, and first few installments saw activity reminiscent of the previous decade. But after an initial burst of collecting reports and myrmecological musings, participation waned to the extent that Gordon now grovels for submissions and installments arrive months behind schedule. What happened?

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Hide and Seek?

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 Formica accreta, Northern California

I wish I could say I knew what these ants were doing.  Hiding from the photographer, perhaps?  Formica of the fusca species group are notoriously shy insects, but not all of these ones seemed to be equally spooked.

photo details: Canon MP-E 65mm 1-5x  macro lens on a Canon D60.
f/13, 1/200 sec, ISO 100
Twin flash diffused through tracing paper.
Levels adjusted in Photoshop.

Ant Course 2008: Venezuela

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Ant Course 2008 is scheduled for Venezuela this August. The Ant Course, now in its 8th year, gives students an introduction to myrmecology with a decidedly taxonomic focus. More than just an academic exercise, the course serves as a meeting place where newcomers can mingle with an all-star cast of instructors, a superb social networking medium for aspiring ant scientists.

Admission to the Ant Course is competitive, with double the number of applicants than seats. I have been on the admissions committee in past years, and though I can’t speak for this year’s course I can share what the admissions folks looked for previously.

The ideal candidate is already pursuing an academic career. Most will be graduate students, post-docs, or assistant professors whose research requires taxonomic knowledge, especially in the region where the course will be taught. This year’s course is in South America and will favor students doing taxonomic revisions of Neotropical ant genera or biodiversity surveys of Neotropical habitats. As the course emphasizes taxonomic diversity, prospective students whose research covers a broad range of ants will be favored over those whose research focuses on a single model organism. Letters of recommendation from scientists known to the instructors will be helpful.

Prospective students who do not actively conduct research and are unaffiliated with a university, museum, or other research institution stand little chance of admission. Don’t despair, however. The text for the North American version of the course has just been published as a handly little guide, and students denied for admission one year are typically given priority the next.

More information here: Ant Course 2008.

New Species: Lordomyrma vanua

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Lordomyrma vanua Lucky & Sarnat 2008
Fiji
image by A. Lucky & E. Sarnat

Last week’s Zootaxa contained a excellent short paper by Andrea Lucky and Eli Sarnat describing a pair of new Lordomyrma species, including the beautiful L. vanua pictured above. As is true of most insects, Lordomyrma vanua remains a largely unknown quantity. It has been collected just twice, both times from the island of Vanua, in Fiji, for which it is named.

Source: Lucky, A. & E. M. Sarnat. 2008. New species of Lordomyrma (Hymenoptera: Formicidae) from Southeast Asia and Fiji. Zootaxa 1681: 37-46.

Megalomyrmex symmetochus: social parasite

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We often think of ants as paragons of hard work, but a surprising number of species get by through mooching off the labor of others. Trachymyrmex fungus growers, the larger spiny ants pictured above, do things the old-fashioned way. They dig their own nests, send workers out to gather food, and meticulously cultivate the fungus garden that serves as the primary food source for the colony.

Then, along comes the slim, sneaky Megalomyrmex symmetochus. These little parasites hollow out a cozy little nest within the Trachymyrmex garden and spend their time leisurely consuming the brood of their oblivious hosts. An easy life, for an ant.

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photo details: Canon MP-E 65mm 1-5x macro lens on a Canon 20D
f/13, 1/250 sec, ISO 100
flash diffused through tracing paper
levels adjusted in Photoshop
(Thanks to Rachelle Adams for letting me photograph her lab colonies)

 

Ant Research Roundup

Finally, a solid taxonomy for the Australian Aphaenogaster:

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Shattuck, S. 2008. Australian ants of the genus Aphaenogaster (Hymenoptera: Formicidae). Zootaxa 1677: 25-25.

ABSTRACT: The Australian species of the myrmicine ant genus Aphaenogaster Mayr are revised. Eight species are recognised, four of which are described as new. The species include barbara sp. n., barbigula Wheeler (for which a lectotype is designated), kimberleyensis sp. n., longiceps (Smith) (with its newly recognised synonym, flava Emery), mediterrae sp. n., poultoni Crawley, pythia Forel (for which a neotype is designated) and reichelae sp. n. Aphaenogaster is widely distributed across eastern and southern Australia (except Tasmania), with isolated populations in northern Northern Territory and northern Western Australia. Species occur in a range of habitats from rainforests through open woodlands and can be of significant economic importance because of damage caused by their nests.


Pin-headed ant larvae explained:

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Masuko, K. 2008. Larval stenocephaly related to specialized feeding in the ant genera Amblyopone, Leptanilla and Myrmecina (Hymenoptera: Formicidae). Arthropod Structure and Development. 37: 109-117.

ABSTRACT: Larvae of the ant genera Amblyopone, Leptanilla and Myrmecina have unusually minute crania. This characteristic is here termed stenocephaly. To study it in detail larvae of the three genera were examined morphometrically and histologically in comparison with other non-stenocephalous larvae of the genera Cryptopone and Manica. The stenocephalous larvae are very specialized, in that their supra- and sub-esophageal ganglia are entirely displaced into the anterior thoracic segments, apparently as a consequence of the small cranial capacity. In Amblyopone and Leptanilla the small cranium appears to facilitate group feeding by a large number of larvae on the whole, intact bodies of the specialized centipede prey characteristic of these genera. In Myrmecina, the small, elongate head adapts the larva to consume the contents of the partly opened bodies of oribatid mites, which are the specialized prey of this genus. Therefore, stenocephaly seems to be a larval morphological adaptation facilitating specialized predation in these ants. These morphological specializations by ant larvae, and active larval involvement in prey dissection are possible because ants rear the larvae without confining them in cells. Acellular nests, a universal feature in Formicidae, may thus facilitate larval adaptations of benefit both to the larvae themselves and to the functionality of parental colonies, allowing them more efficiently to exploit accessible prey through well-integrated cooperation between adult and immature individuals.


Attines aren’t the only ants with a fungal mutualism:

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Schlick-Steiner et al. 2008. Specificity and transmission mosaic of ant nest-wall fungi. PNAS 105: 940-943.

ABSTRACT: Mutualism, whereby species interact to their mutual benefit, is extraordinary in a competitive world. To recognize general patterns of origin and maintenance from the plethora of mutualistic associations proves a persisting challenge. The simplest situation is believed to be that of a single mutualist specific to a single host, vertically transmitted from one host generation to the next. We characterized ascomycete fungal associates cultured for nest architecture by the ant subgenera Dendrolasius and Chthonolasius. The ants probably manage their fungal mutualists by protecting them against fungal competitors. The ant subgenera display different ant-to-fungus specificity patterns, one-to-two and many-to-one, and we infer vertical transmission, in the latter case overlaid by horizontal transmission. Possible evolutionary trajectories include a reversal from fungiculture by other Lasius subgenera and inheritance of fungi through life cycle interactions of the ant subgenera. The mosaic indicates how specificity patterns can be shaped by an interplay between host life-cycles and transmission adaptations.

Friday Beetle Blogging: Adranes Ant-Nest Beetle

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Adranes ant-nest beetle
California

The most exciting finds are often the least expected. I stumbled across this odd little beetle while collecting ants several years ago in northern California. It was tiny, only a few millimeters long, with a little blind nubbin for a head whose sole purpose seemed to be supporting antennae that looked like a pair of cricket bats. The Lasius ants whose nest played host to this strange creature did not appear to pay it any particular attention. Ants are normally rather vicious towards interlopers, so their nonchalance often reveals successful infiltration by a clever parasite.

From the perspective of a hungry arthropod, ant nests are oases in the desert. Ants concentrate impressive amounts of well-defended resources. Most would-be moochers are turned away with a little formic acid, but anyone able to crack the ants’ defenses can help themselves to the riches. Getting around the guards requires a fair amount of specialization, and insects found in ants’ nests usually show strange morphologies or enticing chemical mimicries. Although I didn’t know the identity of this beetle, it clearly showed the telltale signs of a well-adapted parasite.

I vaguely recalled seeing a painting of an insect that looked like this in Hoelldobler and Wilson’s now-classic “The Ants.” When I revisted the illustration, it turned out to be a European species of rove beetle in the genus Claviger. It was similar to my mystery beetle but with several distinct antennal segments instead of the blunt club. With that lead in hand, a bit more looking about revealed my beetle to be in the closely-related American genus Adranes, also recorded to be an ant-nest inhabitant. As is true of most insect species, no-one knows much else about it. It likely mimics the odor of the ant larvae and tricks its hosts into feeding it.

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Ants from a Kilometer Up

So you like insects, but can’t be bothered to get up from your computer to go look for some? Google earth to the rescue!

South of Tucson, Arizona (31°38.097’N 111°03.797’W) I found this lovely aerial image. Visualized from an elevation of about a kilometer and a half, it shows a hill just west of I-19 covered in freshly-sprouted grass. Except, there’s this strange pattern of evenly-spaced polka-dots:

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What could account for the speckles? Alien crop-circles? Bizarre gardening accidents?

Why no, those are the nest discs of one of our most conspicuous insects in the Sonoran desert, the red harvester ant Pogonomyrmex barbatus. Down on the ground it is harder to get a sense of the even spacing of the nests, but the discs are plenty obvious. The ants keep the large area around their nest entrance free of vegetation and other unwanted debris. Below is a photo I took south of the Huachuca mountains, not far from the google earth image above:

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Even closer-up, here are the engineers:

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North American Pogonomyrmex aren’t the only ants whose engineering prowess is visible from low-earth orbit. Some of the more spectacular leafcutter ants in South America make even larger mounds. The image below the fold is also from Google Earth, 1 km over the Paraguayan Chaco (24°06.914’S 57°22.240’W).

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Parasite turns ants fruity

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Here’s a story about a parasitic nematode that turns black ants into ripe red berries. What’s this about?

The parasite needs to get its eggs from an infected ant to healthy ants. Apparently it hasn’t been successful the old-fashioned way, just broadcasting its eggs about the environment. Instead, these little worms have figured out a far more effective egg delivery vehicle: birds.

Ants of the genus Cephalotes often feed from bird droppings (for instance, see here). If a parasitic egg can get itself into a bird’s digestive system, it’ll wind up in a juicy fecal pellet where it may be inadvertently picked up by hungry ants.

The manner in which the nematode reaches a bird is particularly clever: parasites of reproductive age make the infected ant look like bird food. The rounded end of the ants’ abdomen (the gaster) turns from black to red, and infected ants raise their gasters high in the air where they appear like ripe berries. Bird eats ant, bird poops out parasite eggs, ants eat egg-laden poop, ants begin to resemble bird food, and the cycle continues.

Also:

photos by Steve Yanoviak