How many errors can you spot?
Alex Surcică , of facebook’s Digital Museum of Natural History, has created this wonderful poster covering a diversity of beetles from eastern North America. You can order a copy clicking through the link.
The poster represents a tremendous effort on Alex’s part- 90 photographs of stubborn, difficult to control live insects composited into a single montage- yet even this work records just a minuscule slice of beetle diversity. You’d need at least 12,000 such posters to cover the documented diversity of beetles. Never mind the 10,000 or so additional posters required to address the remaining undescribed species. The number of beetles is nearly incomprehensible.
Meet Peckhamia, a charmingly ant-like jumping spider:
Peckhamia avoids being eaten by predators by appearing like an ant rather than a spider. This defense is two-fold. Ants aren’t as palatable as spiders to most general predators, and spider-specialized predators might not recognize Peckhamia as food.
For mimicry to work optimally, though, spiders must inhabit places with plenty of ants. Not the easiest task, since ants eat spiders. And because most ants have poor vision, the spider’s physical resemblance to ants isn’t much help.
So how does this ant mimic spider escape being attacking by ants?
A new paper by Divya Uma et al in PLoS One provides a partial answer: Peckhamia doesn’t smell like a jumping spider. It doesn’t smell like an ant, either, so it’s not a chemical ant mimic. In fact, Peckhamia doesn’t smell like much at all. Look at the results of Uma et al’s cuticular hydrocarbon assay:
Cuticular hydrocarbons are chemicals that impart odor, and Peckhamia has rather low amounts of these. It’s a stealth spider!
The researchers also measured predation rates by spider-eating wasps on Peckhamia (lower than on related species), and rates of attack by ants (lower against mimic spiders than against non-nestmate ants). I’d have liked to see the next step of actually painting hydrocarbons on the mimics to gauge the ants’ reaction, but even without that experiment the odorlessness of Peckhamia is an intriguing observation.
[for more ant mimics, see my ant mimic photo gallery]
source: Uma D, Durkee C, Herzner G, Weiss M (2013) Double Deception: Ant-Mimicking Spiders Elude Both Visually- and Chemically-Oriented Predators. PLoS ONE 8(11): e79660. doi:10.1371/journal.pone.0079660
If you haven’t seen MinuteEarth, their concise explanatory videos are worth your time.
Myrmecology continues apace! This week saw the publication of a particularly interesting new ant genus, Cyatta, from Brazil.
Why the excitement over this discovery? First, Cyatta is an attine fungus-growing ant, and attines are a multi-species system and a rich model for studies of co-evolution across microbes, fungi, animals, and plants. Attines are farmers, cultivating a specialized underground fungus from bits of detritus or, in the case of the spectacular leafcutters, from live vegetation. The ants also foster an array of organisms that live on their bodies, some of which produce agrochemicals that protect their gardens from weeds. Any new species of attine enriches our ability to study this system.
But Cyatta is not just another Trachymyrmex. This new ant occupies an unusual space in the attine tree. Cyatta, along with its sister Kalathomyrmex, doesn’t share recent ancestry with other attines, instead tracing its origin to near the origin of the whole tribe. As such, it will provide another perspective from which to triangulate our inferences of how ant agriculture developed.
Here is the molecular tree:
For example, Cyatta gardens resemble those of Kalathomyrmex and Mycocepurus, strengthening our inference that simple suspended gardens were the form used by the ancestor of all neoattines. And the presence of larval anchor hairs employed in other genera to hang larvae along the sides of the nest chamber (see Clint Penick’s research), suggests that brood-hanging may have been present in the early attines but was subsequently lost.
One final gripe- because I always have a gripe- is that all authors of the paper are also listed as authors of the genus and species. This makes the formal name for the new ant an impressive:
Cyatta abscondita Sosa-Calvo, Schultz,
Brandão, Klingenberg, Feitosa, Rabeling,
Bacci, Lopes & Vasconcelos 2013
This moniker will be a handful for people who handle taxonomic databases, or for taxonomists who will need to write about this ant. I doubt all authors contributed equally to the written description embedded in the paper; surely a separate, smaller authorship for the description would have made for a less cumbersome name.
In that vein, does anyone know if there is a longer authorship for any animal species? This is the largest I’ve seen.
Sosa-Calvo J, Schultz TR, Brandão CRF, Klingenberg C, Feitosa RM, et al. (2013) Cyatta abscondita: Taxonomy, Evolution, and Natural History of a New Fungus-Farming Ant Genus from Brazil. PLoS ONE 8(11): e80498. doi:10.1371/journal.pone.0080498
Many of you at the Entomological Society of America Meeting in Austin this week inquired about the simple black standout mounts on display in my booth. Here is how to order them through my website.
1. Choose a photograph. Click on the image you want and it will open large on your screen. At the lower right you will see an “Add to Cart” button. Click it, and choose “this photo”.
2. Choose your paper type and size. I prefer “lustre” for most prints, although “metallic” is zingier for subjects like metallic beetles with a naturally reflective sheen. The prints on display at ESA in Austin were 16×24″ on lustre paper. Click “checkout” when you are ready.
3. Add the mount. In the next page, you choose from a variety of mats, frames, and mounts.
The 3/4″ standout mounts can be found in the “mounting” tab. I also always add the protective coating from the 3rd tab.
4. Proceed to checkout! Click “save” to move to the page where you add your shipping address and payment information.
If you’d like a signed print, email me (alwild [at] myrmecos.net) and I’ll put in the order to ship to me so I can sign it before sending it along to you. Signing entails an extra shipping charge, depending on where in the world you live.
If there is one single event that generates buzz among insect scientists (ha, ha), it’s the annual Entomological Society of America meeting. This year’s conference, held next week in Austin, Texas, is rumored to be the largest ever. Over 3,000 people are expected to share their latest research, trade tips on field and lab methods, and hunt for new jobs, new students, new employees, and new collaborators. ESA is also tremendous fun, a place to meet like-minded bug nerds and catch up with old friends.
The hashtag- of course there is a hashtag- is #EntSoc13.
The Austin meeting will be a first for me. Not my first ESA- I’ve been many times as student and researcher- but my first time as a professional photographer. I have rented a booth in the exhibitor area.
A booth means I have a fixed place where people can find me to chat about ants, photography, or even ant photography. And I’ll be easy to find. That’s me in #123, the corner stall next to the posters:
If you’re at the meeting, and I know many readers of this blog will be, please feel free to drop in and introduce yourself.
I am also bringing a few items to sell, hoping to offset the not-insignificant cost of renting the space:
- Myrmecos t-shirts ($22)
- Bee caste poster ($10)
- Postcards ($1; set of 6 for $5)
- Fine art prints ($30-$250, depending on size & mount)
I wish I had time to write about a pair of significant ant-plant papers that came out this week, but as it is I’m preparing for my booth at the Entomological Society of America meetings next week. You’ll want to read both of these, as they indicate the depth and complexity of ant-plant relationships.
1.In water-stressed habitats, plants invest more in their Azteca ant guards. A new study by Beth Pringle:
The strength of ecological interactions, measured as the costs or benefits sustained by each species, depends on the environmental context in which the interaction occurs. Stressful environmental conditions should favor trading between species that can produce a given resource or service at the lowest cost. Mutualisms, in which both interacting species incur a net benefit, may thus strengthen under stressful conditions. Here we examine an ant–plant mutualism, in which plants provide food and housing for ants and ants defend plants against leaf-eating insects, along a four-fold annual precipitation gradient comprising tropical sites in Mexico and Central America. We show that the strength of the mutualism, in terms of carbon investment by plants and leaf defense by ants, increases as water availability decreases. Carbon shortages are more frequent where water is scarce and increase the risk that plants will die if all of their leaves are eaten by herbivores. Trees appear to invest more in ant defenders when water is scarce to insure themselves against extreme herbivory. Water availability thus indirectly determines the outcomes of this ant–plant mutualism, which suggests that the increasing frequency of extreme climate events in the tropics will have important ecological consequences.
(Pringle EG, Akçay E, Raab TK, Dirzo R, Gordon DM (2013) Water Stress Strengthens Mutualism Among Ants, Trees, and Scale Insects. PLoS Biol 11(11): e1001705. doi:10.1371/journal.pbio.1001705)
2. Swollen thorn acacias nutritionally entrap their Pseudomyrmex partners by disabling their ability to digest anything other than Acacia nectar. A new study by Martin Heil:
Mutualisms require protection from non-reciprocating exploiters. Pseudomyrmex workers that engage in an obligate defensive mutualism with Acacia hosts feed exclusively on the sucrose-free extrafloral nectar (EFN) that is secreted by their hosts, a behaviour linking ant energy supply directly to host performance and thus favouring reciprocating behaviour. We tested the hypothesis that Acacia hosts manipulate this digestive specialisation of their ant mutualists. Invertase (sucrose hydrolytic) activity in the ant midguts was inhibited by chitinase, a dominant EFN protein. The inhibition occurred quickly in cell-free gut liquids and in native gels and thus likely results from an enzyme–enzyme interaction. Once a freshly eclosed worker ingests EFN as the first diet available, her invertase becomes inhibited and she, thus, continues feeding on host-derived EFN. Partner manipulation acts at the phenotypic level and means that one partner actively controls the phenotype of the other partner to enhance its dependency on host-derived rewards.
(Heil M, Barajas-Barron A,Orona-Tamayo D, Wielsch N, Svatos A (2013) Partner manipulation stabilises a horizontally transmitted mutualism. Ecology Letters. http://dx.doi.org/10.1111/ele.1221)
See also Nat Geo’s story, written by Ed Yong.
In an evolutionary sense, the answer isn’t clear. A recent molecular study suggests Atta may be no more than a derived lineage within a larger Acromyrmex, and that our distinction is artificial.
But what if you just want to key a specimen to one or the other? That’s easier. Count the spines on the front of the thorax- the promesonotum- you’ll find that Acromyrmex sports three pairs, while Atta has just two.
As an exercise, see if you can identify the ants in the following images:
The impressively moustached Pheidole bigote was described from Chiapas by Jack Longino in 2009. What’s up with the bizarrely plush facial adornment? No one knows. Seems like there’s a lot of that going around these days.