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]