Microbes Play a Role in Creating New Species.
Recent experiments conducted by Seth Bordenstein and Robert Brucker at Vanderbilt University in Nashville, Tennessee suggests that two related species could interbreed only if their gut microbes were compatible. In the experiments, the scientists tried to breed different species of a parasitic wasp called Nasonia. Two of the species, X and Y, were closely related in terms of evolution while the third, Z, was more distant. It became clear from the experiments that Z could not breed with X and Y unless Z’s gut bacteria were removed. Once sterilized of bacteria, Z could they successfully mate with X and Y and produce fertile offspring. If these result hold up in other animals, it would mean that gut bacteria have an important role in speciation and that in turn would require a major tweak to the theory of evolution.
Seaworld’s Whale of a Controversy.
An upcoming documentary film entitled “Blackfish,” has ignited a firestorm between the filmmakers and Seaworld’s executive brass. The documentary is highly critical of the manner in which Orca whales are treated in captivity at Seaworld and displayed to the public. It also touches on several lethal incidents between captive Orcas and people. Rather than keeping a low profile and letting the film run its course, Seaworld has launched a frontal assault on the movie by engaging a public relations firm and providing interviews that depict the film as slanted and inaccurate. The filmmakers, however, are not upset by the controversy, calling Seaworld’s publicity generating campaign a “gift that keeps on giving.”
Plants Less Helpful During a Heatwave.
We rely upon plants to remove dangerous ozone from the air. Ozone is linked to various illnesses, both respiratory and cardiovascular. Plants remove ozone by opening their stomata, small holes on the leaf surface. Unfortunately, during a heatwave, plants tend to keep their stomata more tightly closed in order to reduce the loss of water. As a result, excessive heat makes plants less effective at removing ozone from the air.
Bees, Flowers and Fidelity.
Certain species of bees tend to pollinate specific species of flowers. This relationship is essential, especially to flowering plants, which depend upon the visiting bees for reproduction. Researchers at the University of California, Santa Cruz wondered what would happen if some bee species were artificially removed from an environment. Would the remaining bee species remain loyal to “their” plants? The experiment was conducted by catching and removing one bees species, which left the remaining bee species with much less competition. The result was that the remaining bees, suddenly having more plants to choose from, drifted away from some of their otherwise favored flowering plants and instead visited those that usually were unavailable to them. The jilted flowers showed the effect: they produced 30% fewer seeds. The experiment points out the hard to predict threats from a loss of biodiversity.
Madagascar’s Rate of Speciation on the Decline.
Madagascar, one of the world’s largest islands, has been isolated for some 90 million years. It has been one of the most prodigious producers of new species, and today accounts for 3% of the world’s species even while occupying only 1% of the earth’s landmass. However, although scientists believe that the rate of new species on the island has been slowing down, they are not sure why. It could be that there is a limit to Madagascar’s, or any other region’s diversity, which is the main engine of speciation. In any event, the decline seems to have taken place over several million years, and therefore it is unlikely that human intervention is at issue.
For many years, even experts believed that cheetahs’ tremendous speed came at the expense of overheating. The popular view was that cheetahs had a lower kill percentage than other wild cats because they had to abandon a hunt when they got too hot. Although that view had been backed by a study based upon captive cheetahs, a new study suggests that it is wrong. More careful monitoring of cheetahs while they hunt, both successfully and unsuccessfully, shows that they do not tend to overheat. Instead, what might be at play is that after a successful kill, cheetahs become extremely wary of predators, especially hyenas, and the tension caused by this stress response is what increases body temperature.
If you think that this year’s cicada infestation was an exercise in noise avoidance, take a look at the bushcricket. A recently identified species of bushcricket can produce ultra-high frequency sounds up to 110 dB, or as loud as a power saw. The insect’s trick is called ‘stridulation‘ by which it rubs one of its wings against a series of “teeth” on the other wing. It is the male cricket who is responsible for this racket, which is the only effective way of calling distant females to mate.
Hero Shrew Has Hero’s Backbone.
Sometime during its evolution, the hero shrew developed a very strange vertebral structure. Its has ten lumbar vertebrae (humans and most other mammals only have five) and they lock together to form a super strong structure. The hero shrew’s backbone is five times more massive than is called for by its weight. In fact, there are witnesses to a full grown man standing on the back of a tiny hero shrew without harming it. The clue to why the hero shrew developed such an odd backbone may lie in its habits and habitat. It eats beetle larvae in the lowland forests of the Congo, and it puts it back into its work by pushing against Palm trunks and lifting up logs to get to its dinner.
Peacock Displays — It’s In the Eye of the Beholder.
Peacocks perform one of the most intricate and colorful courtship displays in nature. Curious scientists wondered, however, exactly what the peahen was looking for during the displays. To find out, they used sensitive eye tracking cameras and watched what the peahen watched during the male’s repertoire. It turned out that the peahens only appeared to be interested in lower portion of the feather train, possibly assessing the train’s width, while mostly ignoring the upper train of feathers. Next, the researchers will use the tracking technology on other peacocks to see what they are watching when they assess the displays of other males.
Homing Pigeons Use Mental Map and Smarts.
A new study of homing pigeons shows that they can find their home loft not by robotically calculating north-south coordinates, but by using a mental map. The pigeons were tested by using two lofts — one with which they associated with food and the other that was their home base. Two sets of pigeons, one satiated with food and the other hungry, were released from an unfamiliar location. As the researchers predicted, the hungry pigeons charted a course to the food loft while the fed pigeons went straight to the home loft. The research shows that pigeons can tell where they are by topographical clues and can maintain different maps in their brains, which allows them to actually choose between different target locations.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
|« Previous Post||Next Post »|