Spiders' Webs Hum With wealth of Information for hunting
Like strings on a guitar, spider silks can vibrate along a range of frequencies, transmitting information about prey, other spiders and even the condition of the web, researchers say. Spiders have bad eyesight and are known to rely on the vibrations of their webs to alert them to the presence of captives. To discover more about the vibrations, British scientists fired lasers and bullets at individual spider strings and used ultra-high-speed cameras to record the results. They reported in the journal of Advanced Materials that the strings vibrated across a wider range of harmonics compared with other materials, and that the type of vibration varied with the type of impact and the quality of the silk. The vibrations help a spider determine what sort of prey has landed. Spiders can also produce different kinds of silk, "tuning" their webs to the environment and hunting conditions. The findings could aid in the development of new technologies, such as tiny, lightweight sensors or microphones, Oxford researchers said.
sea Catfish Whiskers Track Prey with ph detection
Japanese sea catfish have an unusual advantage when hunting in pitch-dark waters: Their whiskers can detect changes in acidity. John T. Caprio, a physiologist at Louisiana State University, was studying how chemical stimuli were encoded by a catfish's taste system when he noticed a strong reaction from the whiskers. He found previously undetected sensors on the whiskers were responding to the effect the chemical was having on the water. "This fish is a swimming pH meter, and its accuracy was as good as pH meters I was using in the lab. If you drop the pH less than one-tenth of a pH unit," he said, the fish's sensors "start firing like machine guns." The research was published in the journal Science.
SALT makes male butterflies brawnier, females brainier
All that roadside salt laid down in the winter is changing the bodies and brains of butterflies, University of Minnesota scientists said. The discovery, described in the Proceedings of the National Academy of Sciences, shows that the practice could be altering the physiology of animals. Study co-author Emilie Snell-Rood, a biologist, said, "After experiencing my first Minnesota winter, I began wondering how road salt might be affecting the development of organisms along roadsides." She and her team found that the monarchs that ate salty roadside plants had far lower survival rates (40.5 percent) than those fed pristine prairie grasses (58.2 percent). Salt seemed to have another effect: The males bulked up on thoracic muscle (responsible for moving wings and legs), while the females seemed to get brainier, devoting more volume to neural tissue. The team warned that it could have significant long-term evolutionary effects on a range of species.