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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).
Kindly accept my apologies for not writing a post yesterday. I am traveling the Great Lakes and Canada and will try to update when I am able. Today I am in Chicago. As I was looking out at Lake Michigan, I wondered whether there were any catfish native to the vast body of water– which is so large it might as well be considered a freshwater sea.
As it turns out the lake is home to channel catfish (Ictalurus punctatu), the quintessential North American siluriform. The channel catfish is a hardy omnivore which dwells in rivers, lakes, and ponds from southern Canada to northern Mexico. They eat smaller fish, arthropods, worms, seeds, and just about any other edible thing which will fit into their mouths. Channel catfish are nest breeders. If the female catfish is unable to find a promising crevasse in which to lay her eggs, the male will arrange logs and rocks into a nesting bed for her. He then guards the eggs until they hatch and even stays with the fry while they are very small (although if he is unduly disturbed he might eat the eggs and start all over again!).
While the channel catfish are hardly as flashy as some of the exotic catfish we have covered here, they are vastly successful organisms. They can also grow to be fairly large and specimens measuring up to 23 kg (50 pounds) have been caught (although such giants are quite old and rare). Although the catfish live naturally in Lake Michigan, they are also raised on farms throughout the American south (indeed they are the “Delecata” mentioned in this post about international catfish trade wars). Channel catfish have been introduced in parts of Europe, Malaysia, and Indonesia, where they are now causing havoc among native species.
But Channel catfish here in the Great lakes are facing their own invasive threats. Lake Michigan has been colonized by wave after wave of invasive animals. Some, like the omnipresent zebra mussels, are harmless to catfish (albeit infuriating to humans). Others like the sea lampreys (Petromyzon marinus) are not so benign for catfish. The jawless lampreys are vampires which attach to the bodies of catfish (and a wide variety of other native Great Lakes fish) and then rasp a hole in the hosts’ sides by means of sharpened tongue. Even more alarmingly, the leaping thriving all-devouring Asian carp has been making its way up Illinois’ rivers towards Lake Michigan. The state has been trying to prevent these dangerous fish from getting to the Lake by means of increasingly horrifying devices and stratagems such as underwater electric fences and mass poisonings. So far it has been working but there is still an underwater war raging for Lake Michigan.
Horses are first known to have arrived in Australia in 1788. They came as part of an invasion fleet—the “first fleet,” which consisted of eleven British ships filled with marines, soldiers, “free” (but penniless) crown subjects, male and female convicts, horses, dogs, cats, rats, mice, bedbugs, fleas, smallpox, and a handful of King George’s officers. Some of these various life-forms quickly escaped the hungry sweltering colony on Sydney Cove and began to alter the island continent. The first rogue horses were seen around Sydney in 1804. In subsequent years other colonists and business concerns brought yet more horses. Australians imported “Capers”, robust horses from South Africa. In the North, tiny Timor Ponies (renowned for toughness and the ability to thrive in the tropics) were purchased from Indonesia. Miners brought in hard-headed ponies from Cornwall, Wales, and Dartmoor. Wealthy squatters (land barons) brought in thoroughbreds and Arabians. Farmers brought Clydesdales and Percherons. Most of these horses ended up pulling wagons, ploughing fields, or carrying rich men on their backs—they were domestic horses doing human bidding–but a few lit out for freedom in forests and deserts which had never before known the hoof.
The result of the mixture was the “brumby”, the wild horse of Australia. In a continent where the largest native grazer was the stolid wombat, horses quickly began to thrive. In a few generations, feral horses completely adapted to the harsh arid climate of Australia. Huge herds roam the wasteland (particularly in the Australian Alps).
Thanks to natural selection, brumbies quickly reverted to the appearance of wild ancestral horses. Iliveforhorses.com describes the brumby with no particular enthusiasm:
The Brumby varies in conformation but generally has a heavy head with a short neck and back, straight shoulders, sloping quarters, and strong legs. Their shape is generally poor although the occasional one has a through back to Thoroughbred ancestry and will have some quality, especially in the head region. They can be any color and their height varies but they tend to be small.
The same website is equally censorious about brumby temperament, noting that brumbies, “are, like any feral animal, extremely difficult to capture and tame, and have rebellious and willful natures.”
Brumbies might have poor shapes and willful natures, but they have proven excellent at surviving in the wild. During the 19th century, horses were in such demand that round-ups occurred and wild brumbies were “broken” back into domestication, but as mechanization increased during the 20th century, huge herds of brumbies ran roughshod over the Australian ecosystem. Environmentalists, farmers, and politicians implemented the same solution to this problem which they had first used for the rabbit infestation—the gun. Huge numbers of brumbies were shot for meat and hide (apparently there is still a thriving horsemeat market in Europe). Others were simply left for dead, whether cleanly killed or not. Animal lovers reacted with outrage to the slaughter and have demanded more humane solutions to the brumby problem (such as round-ups or mass sterilization). Implementing these solutions has, however, proven costly (and not entirely efficacious) so the fate of great herds of brumbies has become a political wrestling match between environmentalists on one side and animal lovers on the other. Whether herds are larger or smaller, there is no way to eradicate them entirely. Horses have joined kangaroos, echidnas, koalas, platypuses, numbats, and crocodiles as one of the characteristic natives of Australia.
Ah Florida…sultry weather, orange groves, glistening beaches, pouting beauties, and palm trees…but also walking catfish, killer snakes, and now giant mollusks! The semi-tropical peninsula is prey to wave after wave of exotic animal invaders. The most-recent problem creatures are giant African snails, immense land snails that can grow up to 20 centimeters (8 inches) long. There are three extremely similar species of giant snails which come from West Africa: the giant African snail (Achatina fulica), the giant Ghana tiger snail (Achatina achatina), and the margies (Archachatina marginata). Each snail has a brown swirly shell and grows to be about the size of an adult’s fist.
The giant snails eat over 500 varieties of plants—including the majority of agricultural and ornamental species. They also have a taste for stucco and siding so some Floridians now awaken to discover that huge mollusks are literally devouring their houses. The snails are hermaphrodites and can lay up to 12000 eggs per year. They can survive freezing temperatures.
Authorities continue to investigate how the snails got into the country but increasingly the evidence points to…voodoo.
In the Yoruba creation myth, the entire world was once water. The god Obatala possessed a magic snail shell which contained earth. Acting on instructions from the supreme divinity Olódùmarè, Obatala cast this land upon the oceans, thus creating the continents. Obatala then molded the land into men and beasts–but he possessed an artist’s temperament and thirst. As he crafted the Earth and its inhabitants he drank so much palm wine that his mental clarity became dulled and he made big parts of existence wrong. Eventually he passed out altogether and his brother Oduduwa was left to finish the work and patch up the errors as best as he could. Unfortunately big parts of humanity were assembled incorrectly and these flaws remain in evidence everywhere…
Anyway a mainstay of Obatala worship is the sacrifice of snails (in memory of the primordial snail shell which contained the first earth). Apparently one of Obatala’s worshippers illegally brought some giant African snails into Florida for religious reasons and they escaped from him.
So, to recap, a smuggler who worships a drunken deity brought giant hermaphrodite snails in to Florida as a religious devotion to his addled god. Unfortunately the snails escaped and they are now eating people’s homes. Argh! What is wrong with us? I’m going to go drink some palm wine…
Bilbies are blue-gray in color and they grow to about 29–55 centimetres (11–22 in) in length and 3.5 kgs (8 pounds) in weight. They use their sharp claws to unearth a wide diet of insects, arthropods, larvae, small animals, seeds, fungi, bulbs, and fruit. Bilbies rarely drink—they get all the moisture they need from their food.
But wait a minute! Fossorial Marsupials? Arid scrubland? Short gestation? What does any of this have to do with Easter? Well, due to a century of continent-wide ecological disaster caused by a plague of invasive bunnies, Australians hate rabbits with a burning passion (although of course this was not actually the fault of rabbits but was yet another mistake made by nature’s most problematic children). The Easter bunny is not as popular in Australia as elsewhere—giving an Australian child a candy Easter bunny would be like giving a New Yorker a chocolate Easter rat.
Fortunately Bilbies have boldly stepped in to the Easter bunny’s role. In a land where rabbits are regarded as an abomination, the long eared bilby has become the mascot of Easter. Throughout Australia, bilby-shaped confections and related merchandise are sold as an alternative to Easter bunnies. Additionally a number of children’s books have popularized the Easter bilby who seems to have a touch of animist aboriginal magic. For example a passage from Burra Nimu, the Easter Bilby, describes the dyeing of Easter eggs like a dreamtime myth of the desert:
“[The bilby] knew that eggs meant the start of new life and new hope, so he made his especially beautiful. He painted rich red eggs, the colour of the hot desert earth, and splashed them with bright sparkles, because the desert is full of life…Next, he painted soft green eggs and sprinkled them with the colours of the wild flowers he had once seen, soon after the water fell from the sky.
I always liked the Easter bunny (and don’t get me wrong, I’m still thankful for the baskets of candy and toys he left) but it seems appropriate that his role has been usurped in Australia. By taking over the function of a minor holiday deity, bilbies have gained new prominence as one of the symbols of Australian conservation. Enjoy Easter (or Passover or Mawlid-al-Nabi) and enjoy this little bilbie gallery I have put together!
Yesterday’s post—which featured a gory painting of medieval deer hunting—makes one feel sorry for the poor beleaguered deer, which are surely among the most beautiful and graceful of all animals. And those painted deer were being pursued by crossbow hunters—imagine how much worse things would be with high-powered rifles. Well actually you don’t have to imagine–here in North America, the dominant cervid, the magnificent white-tailed deer (Odocoileus virginianus) was severely overhunted in the 1800’s as hunters shot wild deer and sold the venison at the market. Deer populations crashed down below 400,000. Entire regions of the country lost the white-tailed deer completely. The sacred animal of Artemis was in deep trouble across the United States.
To rectify this situation, the Lacy Act, the first federal wildlife law, was passed in 1900. The law banned the interstate trafficking of venison (along with other wild game). Then the Great Depression and the Second World War came along and everything changed again. During the Depression, rural landholders were forced to move into cities to make a living and land which had been under the plough began to grow back into forest. When World War II broke out a generation of hunters went abroad to shoot at the Axis instead of whitetails. After the war, in the 1950s, a clever biologist named Crockford invented a dart-gun system for capturing white-tailed deer and releasing them into habitats where they had died out. So deer made a comeback but their predators did not. Wolves, grizzlies, cougars, jaguars, alligators, and lynxes were relegated to the deep forest and swamp of protected national parks.
So by the end of the twentieth century, white-tailed deer populations were spiking out of control (heading to well above 30 million) and this in turn had a terrible effect on the forests. When a forest is partially or wholly timbered (or when it is denuded by some natural means such as a tornado) there is a succession of plant growth which after decades leads back to a mature hardwood forest. The first plants to grow back are meadow plants–short-lived annual herbs and meter-tall woody plants. Over the course of years these weeds give way to hardwood seedlings like oak and maple which can tolerate the shade created by the provisional meadow growth. However, in areas overpopulated by deer, the woody meadow plants are nipped up by starving deer and other tree seedlings which can out-compete the great forest trees for nutrient gathering (but which are not shade-tolerant to survive the meadow plants) then flourish. Beeches, wild cherries, or exotic invaders grow up and the trees of the great forest take lifetimes to supplant them (if they do at all). In the meantime the overpopulated deer begin to starve and suffer diseases even as they damage the forests. A strange truth of ecosystems is that predators are nearly as necessary as their prey—even hardy generalists like the white-tailed deer which can live almost anywhere need population controls for their own good (as well as that of the forest). Perhaps the ancient Greeks were wise to decide that their goddess of the wilderness was both a hunter and a protector of animals and trees.
Biologists, foresters, rangers, and sportsmen are all trying to unscramble the secrets to ecosystem equilibrium, but there might not be any real long-term balance. The tropical swamps and forests of the Eocene gave way to the temperate woodlands of the Oligocene (where the first tiny deer developed in Europe) which in turn led to the savannahs of the Miocene which allowed artiodactyl grazers to radiate out across the world. But it is hard to think in such big terms and it is uncomfortable to think about what will come next. Something within me longs for homeostasis—for the right number of lovely deer beneath the tall native oaks and tulip poplars forever and ever.
At the corner of my block there is a small lovely tropical-looking tree covered with candyfloss flowers of princess pink. Since I live in Brooklyn (which occasionally gets very cold), I have been wondering if the tree is a hallucination or some cunning model made of plastic, but it turns out that the tree is a mimosa tree (Albizia julibrissin), aka the Persian silk tree. Like the green parakeets which live in my neighborhood, this little tree is evidently not as tropical as it seems.
A member of the legume family, the small to medium-sized tree has a springy crown which spreads out like an irregular umbrella. Its delicate bipinnate leaves look like fern fronds (or like Mimoseae plants, to which the Persian silk tree is not closely related). The tree has smooth olive colored bark which becomes striped as it ages. It produces dense clusters of down-like pink flowers all summer. These flowers are attractive to bees and hummingbirds. Perhaps the most interesting aspect of the tree 9other than the pretty flowers) is how animated it is—during the evenings or rain storms the leaves close up and the tree takes on a hunched forlorn appearance. When it is sunny and warm it spreads out like a kid on a comfy sofa. Because of this habit the Persians call it “shabkhosb”—the night sleeper. Apparently its Japanese name is similar and the tree has become representative of sleepy summer evenings in Japanese literature and art.
The trees originally came from Asia and are native to a huge swath of the world from Persia to China. In the past two centuries people planted Albizia julibrissin trees everywhere as an ornamentals and, you guessed it, the species has become invasive. It can be found growing wild in the United States from Southern New York west to Missouri and south to Texas. I wonder if my neighbors even planted their specimen or whether it just showed up like all of the trees of heaven which live around every American city.
A tea made out of this tree is used in traditional medicine to ward off confusion and dark feelings and indeed a clinical study by Korean physicians found that the methylene chloride fraction of Albizzia julibrissin extract produced an antidepressant-like effect in mice (most likely by affecting 5-HT1A receptors—a neural receptor shared by humans).
To borrow a page from the timeless style of Sesame Street, this week Ferrebeekeeper is brought to you by the Roman letter Q. Each post will concern a topic which begins with that rare letter. So quench your thirst with quinine water and wrap up in a quaint quilt. There is a reason that the letter Q is worth 10 points in scrabble but I think we can find 5 relevant topics that are not too quixotic (also I’m going to stop using extra q words for effect immediately—please don’t stop reading).
For the first q-themed post, we must travel to the ancient arid continent of Australia. For reasons of geology and tectonics, Australia has been a wallflower in the great continental ballet and has been isolated for the last 40 million years. Thanks to this geographic seclusion, the animals of Australia are much different than the creatures which flourish elsewhere, and Austalia’s mammals are dominated by marsupials like the kangaroos, the wombats, the koalas, and the bandicoots. All of those creatures are herbivores, but there are insectivorous marsupials (like the numbat) and there are marsupial carnivores which prey on the others. Some of the larger orders of marsupial predators have died off as Australia dried out, but a major order of predators remain–the catlike quolls.
Quolls (genus Dasyurus) are solitary, nocturnal mammals which seek shelter in their burrows and dens by day and hunt birds, amphibians, reptiles, and small mammals at night. They are agile all-terrain creatures capable of swiftly moving across the forest floor or through the forest canopy. Quolls kill their prey with a bite to the neck where it joins the head. In addition to being predators, they also scavenge for carrion and they can sometimes be found by picnic areas and rubbish dumps. There are six species of quolls which range in size from 350 grams (12 ounces) to 3.5 kilograms (8 pounds). Four species are located across the Australian mainland while one species inhabits New Zealand. One outlier species, the Bronze Quoll (Dasyurus Spartacus) lives in the savannah of New Guinea. The animals all share a characteristic spotted fur coat and a similar lifestyle. The closest relatives of quolls are the formidable Tasmanian devils (the largest extant marsupial carnivores) and the superficially weasel-like mulgaras.
Unfortunately, quolls are not doing well. Feral cats, dogs, and foxes are much more deft predators and are outcompeting the quolls or eating them outright (although the quolls do get some free meals from the invasive wave of rabbits and rats which have swept Australia). Additionally the quolls are falling victim to an even stranger invasive species. The Cane Toad (Bufo marinus) is a toxic South American toad which was brought to Australia in order to control agricultural pests. The toads secrete a powerful toxin which is potent enough to kill a human (some people ingest cane toad secretions in order to experience the hallucinogenic effects). Cane toads resemble some of the natural amphibian prey species of quolls and the spotted predators eat them voraciously—only to fall sick and die. In order to save the unlucky quolls, a project is afoot to train the predators not to eat cane toads. Wildlife researchers have been dropping small sausages made of cane toad from airplane in quoll habitats. It is hoped that quolls will eat the sausages and become violently sick (but not fatally so). Having had a miserable bad trip, the quolls will then presumably forbear from eating further cane toad flesh.
Behold a dreadful strangling monster! This entity cannot be easily killed by conventional means and it reproduces both by asexually spawning duplicates of itself (at first attached to the parent by runners) and by releasing tens of thousands of wind-born flying pods. When these pods land on something they take root and start to grow—even if it is another tree or a roof or a bit of concrete. This monster comes from the primeval forests of China, indeed it is mentioned in the most ancient Chinese texts, but today it has spread everywhere. It eats toxins and is not affected by most pollutants or even by high doses of toxic metals. It produces a poison which kills plants. If you live in a major city there is probably more than one outside your door right now!
Thanks to the title at the top of the page, perspicacious readers will probably already have guessed that the monster I am writing about is Ailanthus altissima, aka the tree of heaven. This is one of the most successful invasive species out there. People unfamiliar with the plant are probably chortling at my rhetoric, whereas people who do know this tree, especially gardeners, are most likely making murderous gestures and exclaiming wild oaths. The tree reproduces like crazy and it grows with seemingly supernatural speed. Anyone who has tried to garden anywhere near a tree of heaven has spent a great deal of their time pulling up saplings or sawing them down only to see them rise again and again like the fearsome horde of hellspawn which they are. When chopped down the tree grows back with redoubled vigor and produces suckers (basal shoots which grow from the roots and produce independent trees). The tree of heaven may not be a massive clonal colony like Pando, but fighting the suckers and the seedlings and their many offshoots makes it seem like a single malevolent entity. And it is everywhere—when you see a tree growing on top of an abandoned building or sprouting improbably from sheer concrete, it is most likely the tree of heaven.
The tree was not always despised. Eighteenth century European gardeners (under the spell of Chinese gardens and all things Chinese) were beguiled by its swift growth and elegant looks. They brought the tree to Europe in the 1740s and to the United States in 1784, but, as soon as the tree was planted, the honeymoon ended. In formal gardens Ailanthus trees tendency to sucker and set seed became very apparent as did the abominable smell of the male trees which produce a urine-like stench to attract unsavory pollinating insects (European botanists should probably have translated the Chinese name before planting: 臭椿 literally means malodorous tree). The tree’s prettiness though undeniable is not as great as that of other Chinese invasive trees like the lovely Empress tree (which is not nearly as aggressive or malodorous).
Aesthetic concerns were not the sole motivating factor which caused European gardeners to import the fearsome tree. Although the finest silk comes from the silkworm, Bombyx mori, which feeds only on the mulberry tree, a more durable and coarse silk can be produced from the cocoons of the ailanthus moth (Samia Cynthia) which, of course, eats ailanthus leaves. Ailanthus silk is distinctly inferior to true silk in that it does not readily take dyes, but it is durable and pretty in its own right. Unfortunately it proved to be too labor-intensive for western production. Ailanthus moths, the huge saturniid moths, which produce these cocoons also went rogue and are now spreading across North America and Europe in tandem with the trees.
The discerning reader may have apprehended that I am no fan of the tree of heaven. Even literary allusions to the ailanthus are problematic (it is the tree from A Tree Grows in Brooklyn, a novel about alcoholism, poverty, cheating, and misery in early twentieth century immigrant life). However, having said that, Ailanthus altissima demands respect as a supremely effective life form. It is probably the fastest growing tree in North America and is able to grow 2 meters (6 feet) in a year (as I know from cutting down 15 foot tall suckers in my tiny garden). Additionally the tree produces a chemical, ailanthone, which inhibits or prevents the germination of other seeds and is toxic to other trees. Ailanthus altissima can live in locations that are dry, salty, or toxic and can survive on water as acidic as tomato juice. For these reasons as well as its staggering number of wind-born twirling seeds it can be found in industrial or urban wastelands where nothing else grows. It is impossible not to feel a bit of awe for a 50 to 90 foot tall weed.
Not only is the tree is an opportunist which can live by itself in places too dry or poisonous for other trees but its incredible rate of growth allow it to compete with other deciduous trees by quickly growing into unoccupied canopy space (although adult forest trees in healthy woods can probably out-compete it in the long run). The tree of heaven pays a price for its quick growth and heavy suckering. Its life is short and specimens rarely live past 50 years. However one individual tree is not the problem—if you have one tree you already have many. Like the Lernaean Hydra, the tree of heaven is a exponentially increasing monster, but something so tough must have a use. Perhaps a future generation of space colonists living in Konstantin Tsiolkovsky’s fantasy will spend their time wrinkling their noses and wandering why anyone chose to plant such a thing.