Reader question: who discovered the sex of ant workers?

A query from the inbox:

Hi, my question is regarding the gender of the worker ants (and the ant queen). As we all know; they are female, however was this discovered many centuries ago or is this a recent discovery?

I plead ignorance.  I know apiculturists had figured out the sex of worker bees in by the late 1700s, and that by the 1800s it was widely accepted that ant workers were also female. But that’s the extent of my knowledge.

So I’m punting to my diligent readers.  Do any of you know who first observed that ant workers are female?

Read Full Post »

Location, location, location

Widow spider and harvester ants. Hallelujah Junction, California

This young black widow (Latrodectus hesperus) set up shop above the nest entrance of a colony of Pogonomyrmex harvester ants.  It’s an all-you-can-eat buffet, allowing the spider nearly unlimited pickings as the ants come and go.

The spider’s mottled coloration is typical of young widows; they don’t acquire the striking black and red warning garb until maturity.

photo details: Canon 100mm f2.8 macro lens on a Canon EOS D60
ISO 100, 1/200 sec, f/11, MT-24EX twin flash

Read Full Post »

Question: Ritualized Fighting in Harvester Ants?

Here’s a question for my myrmecologist readers.  Has anyone published observations of ritualized fighting among colonies of Pogonomyrmex harvester ants?  I know such behavior was famously studied by Bert Hoelldobler in Myrmecocystus, and that ritual combat has been noted in Camponotus and Iridomyrmex.  The reason I ask is that the pogos in my front yard back in Tucson would engage in what looks like the same sort of behavior.  Ants from opposing colonies stand up on little stilt-legs and push each other about without anyone getting hurt.

I suspect these non-lethal ways of establishing territorial boundaries may be more common among ants than we’d thought, and if no one has recorded ritual combat in Pogonomyrmex it should be worth publishing a note somewhere.  More photos below the fold.

Read Full Post »

Losing an Herbarium

One of the most important collections of South American plants is being shut down. The Utrecht Herbarium in the Netherlands houses nearly 1 million specimens and 10,000 types. When the museum closes we will lose a wealth of knowledge about the flora of a diverse and endangered part of the world.

Read More and Sign the Petition.

Why does this closure bother me?

Public support for biological research is the reason why that field guide on your shelf costs $15.00, instead of the $100 or so you’d be paying if you had to foot the bill for all the research that book is based upon. Our knowledge of the natural world comes in large part from government subsidies such as that supporting the Utrecht Herbarium. There are plenty of other benefits to maintaining natural history collections as well, including giving us abilities to identify and track medical and agriculture pests, to conduct more accurate forensic investigations, and to monitor long-term changes in the landscape.

Speaking personally, my income from photography absolutely depends on having correctly identified insects. That knowledge is directly tied to taxpayer-supported natural history collections. My identifications either come directly from collections (for instance, I put a name on this Apatides beetle by comparing the beetle to specimens in the natural history collection at the University of Arizona), or indirectly through the use of taxonomic keys and guides that are based on collections. This public knowledge creates private profit. I pay taxes back to the government. And through the compounded actions of many thousands of businesses like mine that make use of public biodiversity knowledge, the whole system pays for itself and makes everyone better off.  That’s why I find it so shortsighted every time another collection is closed and more taxonomic experts are laid off.

Read Full Post »

Friday Beetle Blogging: Adranes Ant-Nest Beetle

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.

Read Full Post »

Ants and Plants Gallery

Common caricatures of Darwinian evolution evoke nature as a brutal force, one of ruthless competition in which the strongest prevail. In truth evolutionary processes can be much more nuanced. Under a wide array of conditions, species find Darwinian advantage in cooperative relationships.

Some of the most striking cases of evolutionary partnerships involve the planet’s dominant primary producers, the plants, and the most abundant insects, the ants. Ants are exceptional predators, and several groups of plants have figured out that by housing and feeding resident ant colonies they gain a potent defensive shield against their herbivores and other plant competitors. Ant-Plant associations are apparently beneficial enough for both parties that highly-specialized obligatory relationships have evolved many times.

Why do I bring this up? Because I’ve just posted a new Ants and Plants gallery:

http://www.alexanderwild.com/gallery/4001891

At the moment the gallery contains images of just three such systems: the Neotropical Acacia–Pseudomyrmex and Cecropia-Azteca systems and the Australian Myrmecodia-Philidris partnership. These are just a few of the ant-plant systems that exist, though, there are more equally photogenic ones that I’ve not yet had the luck to photograph.

Read Full Post »