You are currently browsing the tag archive for the ‘ants’ tag.
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.
Hey, look at that! It’s a delicate pale blue butterfly (Maculinea arion) from Europe and northern Asia. What could this ethereal creature have to do with the horror theme which this blog has been following as a lead-up to Halloween? In fact, what does the butterfly have to do with any of Ferrebeekeeper’s regular themes? Butterflies are lepidopterans rather than the hymenoptera we favor here.
As it turns out—the butterfly has a lot to do with hymenopterans. Maculinea arion, or “the large blue butterfly ” to use its not-very-creative English name, may look innocent as a butterfly, but in its larval stage the creature is both appalling and remarkable. Alcon caterpillars are myrmecophiles—which means the caterpillars live in association with ants. Despite the Greek meaning of ”myrmecophile” (to love ants) the relationship is anything but loving on the part of the Alcon caterpillar–unless love is meant in the same way as “to love ham”.
M. arion caterpillars are relentless predators of ant larvae. The way they obtain this fragile foodstuff is remarkable for sophistication and ruthless guile. When a caterpillar hatches, it lives for a few days on wild thyme or marjoram plants. The caterpillar then secretes a sweet substance which attracts red ants which carry the larva back to their tunnels.
Inside the ant hive, the caterpillar produces pheromones and chemical scents which mimic those of the ant queen. It also scrapes a small ridge on its first segment to produce the same noise as the ant queen. The ants are deceived by the caterpillar’s mimicry and they take it to the chamber where they rear their own larvae. The ants wait on the caterpillar as though it were the hive monarch and they even feed it ant larvae—their own undeveloped siblings. Once it pupates, the butterfly scrapes the inside of its chrysalis to continue the deception. When the butterfly emerges from its cocoon the hapless ants carry it outside and guard it as its wings harden—whereupon the butterfly departs to mate and lay eggs on wild thyme or marjoram plants.
The Maculinea Arion is not the only caterpillar to make use of this strategy. The Phengaris alcon butterfly acts in almost exactly the same way. Here is where the story becomes impressively crazy. A parasitoid wasp, Ichneumon eumerus, feeds on the alcon caterpillar inside the ant hive. The wasp infiltrates the hive by spraying a pheromone which causes the ants to attack each other. While they are busy fighting, the wasp lays its eggs inside the caterpillar. The wasp larvae hatch into the body of the caterpillar (which the ants think of as a queen) and they eat the caterpillar host safe in the cloak of this deception.
If an ant hive becomes too saturated with caterpillars it will die and all three species inside the hive will likewise perish). The red ants in this scenario are constantly evolving new pheromone signals to outcompete the caterpillars and wasps—which in turn coevolve with the ants. It’s strange to imagine the troubling world of deception, chemical warfare, and carnage just beneath the ground.