Worldwide, 2005 was the warmest year in a century • At least 128 types of bacteria live in the human stomach
Calling All Wasps
Corn has a perhaps unexpected capacity: retaliation. When a caterpillar chomps on a cornstalk, the plant releases a chemical SOS that summons tiny parasitic wasps no longer than an eyelash. The wasps land on the caterpillar and lay eggs. Within two days, the eggs hatch, and larval wasps crawl into the caterpillar—and eat it. Researchers at the Max Planck Institute in Jena, Germany, have now identified the gene in corn that concocts the plant’s distress signal. After the researchers transplanted the gene into another plant, it sent for a squadron of wasps. The work underscores the elaborate means that plants have evolved to defend themselves, and might be used to help protect crops without pesticides.
The gourds that Native Americans used for millennia as containers did not originate in Africa and float across the Atlantic, say experts led by Bruce Smith of the National Museum of American History. New analyses of ancient gourd fragments in the Americas suggest people carried the plant from Asia about 10,000 years ago. Thus bottle gourds are one of the oldest domesticated species.
Do Dolphins Eavesdrop?
Dolphins emit high-pitched clicks and gauge their distance from objects by listening to the echoes—a way of perceiving called echolocation. But a new study of rough-toothed dolphins, which swim in tightly coordinated formations, shows that only one animal calls at a time. Researchers at the University of Tübingen, in Germany, say the silent dolphins may listen to a pod-mate’s echoing signals for the same reason lazy kids steal glances at a good student’s schoolwork: to save energy.
The American pika is a rabbit relative that lives in the mountains. In recent decades, 9 of its 25 known populations in California, Nevada and Oregon have died out. Donald Grayson of the University of Washington found that pikas, which cannot tolerate sustained heat, have become restricted to higher and higher elevations since their heyday at the end of the last ice age. Now even these climatic sanctuaries are heating up. For pikas, which make hay in the summer to eat during the winter, global warming could be the last straw.