At some point in the first half of the 20th century, a couple of ants hitched a ride on a boat and ended up on Christmas Island, an Australian territory in the Indian Ocean. And so began the rampage of the “yellow crazy ants,” creatures that have been named one of the top 100 most invasive species in the world. On Christmas Island, scientists have now declared an “invasional meltdown” of the original ecosystem [Science News].The latest evidence: The ants are so plentiful and bothersome that they’re preventing birds from feeding on berries, and the birds are therefore failing to disperse seeds around the island.
Researcher Dennis O’Dowd explains that the long-legged yellowish ants earned the named “crazy” because when they are disturbed they run around frenetically. O’Dowd says crazy ants form large super-colonies and cover ground and vegetation in densities of around 1000 ants per square metre. “These ants are three-dimensional foragers,” he says [ABC Science]. The ants can thickly cover the forest floor and swarm up vines and plants.
In ant-dense zones, O’Dowd sees birds stomp and ruffle their feathers as if maddened by crawling ants [Science News]. So for his study, published in Biology Letters, he tested whether the ants’ presence was interfering with native birds’ feeding habits. His team made fake berries out of non-toxic modeling clay and secured them next to real berries; later they looked at the impressions on the fake berries made by the birds’ pecking beaks. They found that in ant-free areas, the fake fruit received twice as many pecks as the fruit in areas swarming with ants. Placing ant traps around the base of a plant also increased the number of pecks. – discovermag
Comment at the end:
1. jerry Says:
September 16th, 2009 at 8:06 pm
use anteaters …
Anteaters are the four mammal species of the suborder Vermilingua commonly known for eating ants and termites. Together with the sloths, they compose the order Pilosa. … Anteaters are one of the surviving families of mammals that occupied South America while it was geographically isolated from an invasion of animals from North America. At one time, it was assumed that anteaters were related to aardvarks and pangolins because of their physical similarities to those animals, but it has since been determed that these similarites are not a sign of a common ancestor, but of convergent evolution. That is to say, they had all developed powerful digging forearms and long, toothless tube-like snouts and tounges in order to make a living by raiding termite mounds. This similarity is the reason aardvarks are also commonly called “anteaters”; the pangolin has been called the “scaly anteater”; and the word “antbear” is a common term for both the aardvark and the giant anteater.
National Zoo SI says:
The largest of four anteater species, the giant anteater may be five to seven feet long, from nose to tail, and weigh 40 to 100 pounds. It has a narrow head, long nose, small eyes, and round ears. Its coarse hair may be gray or brown, with a white-banded black stripe running along the body to mid-torso, and a long, bushy tail, which can be two to three feet long. Its front feet have large claws, which are curled under when it walks. It has poor vision but a keen sense of smell.
The giant anteater detects termite mounds and anthills with its keen sense of smell and tears them open with its strong claws. What we call an anteater’s nose is actually an elongated jaw with a small, black, moist nose, like a dog’s nose. Giant anteaters have a two-foot-long tongue and huge salivary glands that produce copious amounts of sticky saliva when they feed. Termites, ants, and their eggs stick to the tongue as it flicks in and out and the insects are scraped off by the flexing of the lower jaw and swallowed. Anteaters have a very muscular stomach that grinds up the insects and powerful digestive juices to break down their prey. They may eat as many as 30,000 ants in a day. They will also eat ripe fruit if they find it on the ground.