An Oasis for Pollinating Bugs

Many plant species are known to give off heat. Until now, only two have been discovered that can keep their "body" temperatures stable, as birds and mammals can. Now, researchers at the University of Adelaide in Australia have added a third species to that list, the lotus Nelumbo nucifera Gaern.

During the two- to four-days that it blossoms, the plant holds temperatures in its flower between 30 and 35 degrees Celsius (86 and 95 degrees Fahrenheit), even when nearby air temperatures range from 10 to 30 degrees C.

Zoologists Roger Seymour and Paul Schultze-Motel found that the lotus produces about half the heat in its receptacle, the part of the stem that expands to contain the flower's organs. The lotus's petals and its stamens, which bear the plant's pollen, account for the rest of the heat production.

Researchers have suggested that heat production helps a plant's scent to evaporate and ride the winds, attracting insects. But the main purpose, the two researchers write in the current issue of the journal Nature, could be to keep things cozy for insects trapped overnight inside the blossom. Scientists have observed that beetles trapped overnight have fed, mated, then flown free the next day. Thus, the lotus's microclimate is a kind of reward for insects that stop by to pick up pollen, the team suggests.

Out of Oaxaca

The peoples of western Mexico - pre-Columbus - haven't gotten much respect from historians. The natives who inhabited that part of what archaeologists call Mesoamerica were seen as marginal to the larger story of the Aztecs and Mayas. That may be about to change.

Researchers from the Massachusetts Institute of Technology and Florida International University have traced 171 copper artifacts found in Aztec and Mayan towns from as far south as Belize to ore deposits in western Mexico. Nor was that region just the source of raw materials. No other Mesoamerican peoples are thought to have known how to turn the ore into workable copper and bronze.

According to the article in the current issue of the journal Science, the artifacts - from tweezers to bells - served as symbols of religious and political power. This suggests that western Mexicans not only conducted a significant amount of trade with other Mesoamerican peoples, but may also have influenced their religious and ritual behavior.