Discovered: Urban grasshoppers get loud when looking for a mate; carbon dioxide emissions hit record high; meat is full of PCBs and antibiotics; El Niño on the rise.
City grasshoppers look for love, loudly. Out in the woods, with only the wind rustling peacefully through the leaves and a stream babbling nearby, grasshoppers can send forth romantically subdued mating calls. But in the city, all that high-volume background noise makes amorous singles have to speak up. Researchers from Germany's University of Bielefeld have found that Chorthippus biguttulus grasshoppers increase the volume of their low-frequency mating calls to attract partners. "Effects of man-made noise on acoustic communication has only been studied with vertebrates, so far," says lead researcher Ulrike Lampe. "Bow-winged grasshoppers are a good model organism to study sexual selection because females can respond to male courtship songs with their own low-frequency acoustic signal, if they are attracted to a male song." [BBC News]
Carbon emissions continue to climb. Not every new record is one to celebrate. Germany's IWR has reported that emissions rose 2.5 percent last year, putting the world's carbon dioxide output at 34 billion tons. "If the current trend is sustained, worldwide CO2 emissions will go up by another 20 percent to over 40 billion tonnes by 2020," says IWR director Norbert Allnoch. In descending order starting with the highest emitter, China, United States, India, Russia, Japan, and Germany were the worst offenders according to the report. [Reuters]
Meat is full of bad stuff. It's not news that industrially produced meat arrives in grocery stores and restaurants chock full of antibiotics—the CDC has called for a reduction in the amount of drugs used in livestock—but other stuff gets in these animals, and therefore human stomachs, too. A new NIH study warns of PCBs in American meat. These "mostly banned" chemicals are only meant for industrial use, and when they enter the human body, bad things happen. Especially to couples trying to get pregnant. The more PCBs men and women had in their bloodstreams, the more difficult it was for them to conceive, the researchers found. [Gawker]
Batten down the hatches, more El Niño is on the way. Scientists have been puzzling over the slowdown of the Walker circulation—a meteorological feature that affects Indo-Pacific climate heavily—over the past 60 years. Now, the University of Hawaii at Manoa's Hiroki Tokinaga thinks he's been able to understand the causes behind this trend, and he says if things stay on course, we can expect more harsh storms. "Our experiments show that the main driver of the change in the Walker circulation is the gradual change that has taken place in the surface temperature pattern toward a more El Niño-like state," he writes. "We don't have enough data yet to say to what degree the slowdown over the last 60 years is due to a rise in man-made greenhouse gases or to natural cycles in the climate." [University of Hawaii - SOEST]