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Of all of Ferrebeekeeper’s topics (over there at left in the topic cloud) the one which is farthest from my heart but closest to this blog’s purpose concerns the hymenoptera. This enormous order of important insects always offers diverting stories and anecdotes (like the Schmidt sting index or the Asian giant hornet), but the real reason I started writing about them is that the nature of the huge eusocial ant colonies and bee hives mimics the human super colony in eerie and intriguing ways.

Thus we come to today’s horror story concerning Temnothorax ants which live in German forests in unobtrusive rotting logs and suchlike habitats. Temnothorax ants have a disquieting problem: a parasitic tapeworm likes to live within the abdomens of some of the worker ants. However, to the infected ants it does not seem like a problem. They live up to three times longer than their uninfected sisters and, while the other ants rapidly age and wear out, the ones which harbor live tapeworms keep permanent adolescent good looks through their enormously extended lives. Additionally, infected ants exude a sweet chemical which makes them socially appealing to the honest hard-working ants in their own colonies. Uninfected ants seem to misidentify infected ants as queens (or at least as royalty of some sort) and spend a great deal of time feeding, grooming, and caring for them.

This sounds like a pretty delightful deal for infected ants who live like (and are like?) Kanye West, but there are a couple of drawbacks. The infected ants soak up critical resources from the greater hive and reduce its overall efficacy and ability to survive. Infected hives are at much greater risk of destitution or outright destruction from predators. Which brings up the final problem: the parasitic tapeworm’s final life stage does not take place inside the guts of an ant, but rather the tapeworm must be eaten by an ant-eating bird. There, inside the larger predator, it mates and lays eggs which are released by the bird into the forest where Temnothorax ants feed on the rich droppings and are infected.

So infected ants aren’t just dullard aristocrats not carrying their weight. They are actively seeking self-destruction. When birds tear into the nest the infected ants lift up their heads, glisten, and wait for annihilation (while the infected ones are desperately trying to protect the larvae and the queen). Of course the ants (uninfected and infected) do not comprehend any of this. If we were to ask them about their lives the uninfected workers would probably tell us how fortunate they were to meet so many high-status ants and the infected ones would probably try to sell us self-help books about raw food or talk about running for office in Texas.

Here is a Cretaceous drama (including both original players) captured in amber and perfectly preserved for 99 million years. A predatory “hell ant” (haidomyrmecine) was grasping a proto-cockroach (Caputoraptor elegans) in its strange vertical mandibles when a dollop of sap preserved both creatures in resin. Because it was so well preserved, we can see how the hell ant’s mouth parts are completely different from those of modern ants. Today’s ants all have horizontal side to side scissor-like mandibles. The ancient hell ant has scythelike vertical mandibles which meet up with horn like appendages on its forehead (like a platybelodon…if its upper tusks came out above its eyes).
The ant was found in a piece of amber from modern Myanmar and gives us a precious window into the lives of ancient ants (which were seemingly as widespread in the age of the dinosaurs as they are now, yet were also completely different than they are now). The first ants evolved during the Jurassic (170 million years ago) so the hell ant is nearly as far removed from its first ancestors as today’s ants are from it. Sometimes it seems like the way we picture the world–an empire belonging to dinosaurs, Andrewsarchus, or humans–must be ridiculous to ants. To them we macrofauna must seem like ludicrous obscene monsters who dwell in a different world and are doomed to disappear in the immediate future (the same as Kardassians appear to us normal people).
In the aftermath of Hurricane Harvey, we are all worried about the residents of Houston and the Galveston Gulf Coast. Hurricanes and flooding are a deadly serious matter and my heart goes out to everyone dealing with loss or damage caused by the disaster. As Houston residents and first responders worked together to survive and mitigate the floodwaters with boats, pumps, sandbags, and evacuations, they were treated to the (horrible) spectacle of a very different group of social animals responding to the crisis with a different group strategy.
Red fire ants (Solenopsis invicta) are a tough species of stinging fire ants from South America. Like humankind they are invasive generalists which can survive anything and have quickly spread worldwide because of their hardy resilience and various ingenious group strategies. I have been meaning to blog about them because they are a sort of alien red mirror of humanity (and I have been trying to get back to writing about superorganisms and the question of what constitutes an organism anyway). Because of the hurricane, the fire ants have injected themselves into the news cycle, so I am going to mention their flood strategy now and we can return to write about their other interesting behaviors.
Fire ant bodies are waxy and light. They float! But they would all be drowned or swept apart in a serious flooding event (and a single ant separated from the group is effectively dead). Thus when the fire ants sense rising waters they group together in a ball and tightly cling to each other. These living rafts of clamped together ants can float for many days.
If you are in a flooded area and a ball of furious stinging ants floats by you, entomologists and fire ant experts recommend that you not molest it. Like Voltron, the ants can break apart into autonomous fighting units before reforming. Ants do not breathe like people and they drown sort of gradually. We will leave the ants alone and concentrate on human group strategies for getting through crises.
The first known farmers were apparently…ants. Leafcutter ants have been growing fungus on chopped up leaves for at least 50 million years. It is an amazingly long time. Yet, when one thinks of the astonishing range of different “breeds” of animals and crops which humankind has created through artificial selection during the 10 millenia or so years since we started farming, the ants seem a bit lackluster. For all of their workaholic zeal, ants are not as relentless as us in selecting for traits in their crops.
Yet, as we learn more about the ants and their empire, the amazing extent of their symbiosis with the plants they use is beginning to become more apparent to us. Because of the vastly greater timeline of their endeavors, they have coevolved in astonishing ways. An example of this can be found in the homes of Philidris nagasau, a species of leaf cutterant native to Fiji. These ants literally grow their homes out of Squamellaria, an epiphytic plant which grows on tropical trees.
The Economist described the mechanism through which the ants grow a home (or, alternately, the way the epiphytic plant obtains an army of insect servants):
P. nagasau worker ants harvest seeds from their epiphytic homes, carry them away, and then insert them into cracks in the bark of suitable trees. That done, they patrol the sites of the plantings to keep away herbivores, and also fertilise the seedlings as they grow by defecating into hollow structures called domatia that develop in the bases of the plants’ stems. As a Squamellaria grows, its domatium swells (see picture) and develops galleries that can accommodate ants—which then move in. This, and the plant’s habit of growing flowers that generate nectar long after they have been pollinated, provide the evolutionary quid pro quo that makes the relationship between insect and epiphyte work.
It is incredible that the ants grow their own houses. Yet, as one looks more closely at familiar domestic arrangements with this story in mind, they start to seem less familiar. Is farming really as unique as we make it out to be, or does it resemble mutualistic arrangements found throughout the natural world.
We would never say we co-evolved with goats, cows, and horses: their domestication seems like a one way exchange to us. Yet an outside observer might look at our leather sofas, cheeseburgers, cavalry charges, or angora sweaters and come to a different conclusion.
Like bee hives, ant colonies have all sorts of specialized ants. Soldier ants with mighty mandibles guard the hive. The queen ant becomes a gargantuan reproductive machine and pumps out an endless swarm of underlings. Drone ants develop wings to fly high into the air to mate with fledgling queens. Yet the strangest of all ant jobs (to my mind at least) is held by honeypot ants.
Honeypot ants are found in six or seven genera of seasonal ants located in Africa, Australia, Melanesia, and North America. The ants function as living granaries/reservoirs. They find an underground location deep in the hive and use their own bodies as storehouses to protect the hive from drought and famine. As soon as they develop from larvae, the specialized honeypot ants transform into grapelike spheroids capable of ballooning to many time the size of normal ants. During the rainy season, when food is plentiful, worker ants stuff the honeypot ants to the edge of bursting with prey and provender. These living warehouses can store liquids, body fat, and water for long periods in their grotesquely distended abdomens. When the dry season hits and resources become scarce, worker ants stroke the antennae of the honeypot ants and the latter to disgorge their precious stores of liquids and nutrients.
Living deep underground, honeypot ants are seldom seen by people. They were first documented in 1881 by Henry Christopher McCook (a civil war chaplain, polymath, and entomological pioneer). Yet hunter gatherers have known of them since time immemorial. The strange grapelike ants are regarded as a unique delicacy to Australia’s indigenous people who have worked the strange bulbous ants into stories of the dreamtime—the ancient magical creation of the world. Of course the world is not finished and the dreamtime is still ongoing and honeypot ants are out there, engorged in the darkness, doing their part. We just never see them.
Our nation is being invaded! The intruders number in the millions. They are wiping out entire ecosystems, destroying electronics, and setting fires. Fortunately the invading species, Nylanderia fulva, is rather small: each individual measures only 3.2 mm (.12 inches). In 2002 the ants arrived on America’s Gulf Coast from Argentina or Brazil where they live naturally. These ants are called Nylanderia fulva because of their brownish yellow fulvous color, but in America they are more commonly known as crazy ants (thanks to their erratic and non-linear walking patterns) or Rasberry ants—in honor of Tom Rasberry a Texas exterminator who discovered them in Texas.
The crazy ants have spread extensively in Texas and Florida and they have footholds in Mississippi and Louisiana. They are highly successful foragers and hunters of small arthropods and, like some other ants, they farm aphids (!). Nylanderia fulva is capable of forming extremely large hives with multiple queens—which gives them surprising immunity from many common American insecticides and ant-killing chemicals. They are out-competing native fire ants and changing the micro-fauna of the areas where they are flourishing.
For whatever reason, crazy ants are attracted to electronics. Because of their small size, they climb inside all sorts of switches, circuit boxes, and electric gizmos. If an ant stumbles into a transistor and dies, its corpse emits a chemical which causes fellow hive members to rush to the scene (this is an evolutionary strategy for fending off attackers). Unfortunately, the reinforcement ants are themselves electrocuted which causes a grim feedback scenario. These ant death spirals can cause electronics to become disabled, or switch permanently on/off, or just catch fire (since they are jam packed with electrified ant corpses).
Tamandua is a genus of arborial anteaters with two species, the southern tamandua (Tamandua tetradactyla) and the northern tamandua (Tamandua mexicana). Tamanduas have prehensile tails which help them grip the trees, bushes, and scrub where they hunt for ants, termites, and bees (which they vacuum up through a tubular mouth or capture with a 40 cm long sticky tongue). The two species inhabit a large swath of the Americas—the northern tamandua ranges from Mexico down through Central America and west of the Andes through coastal Venezuela, Columbia, and Peru. The southern tamandua inhabits the entire area surrounding the Amazon basin and ranges from Trinidad, through Venezuela, the entirety of Brazil, and into northern Argentina. Tamanduas weigh up to 7 kilograms (15 pounds) and grow to lengths of about a meter (3 feet).
Tamanduas have immensely powerful arms which they use for climbing and ripping apart ant and termite colonies. If threatened they hiss and release an unpleasant scent (they can also grapple by means of their formidable arms and huge claws). The creatures spend much of their time in trees and they nest in hollow trees or abandoned burrows of other animals. Tamanduas can live up to nine years. They are widespread but comparatively scarce.