By shifting the positions of their flowers, two tropical species keep their blooms at comfortable temperatures for pollinators, say researchers.
Ipomoea pes-caprae and Merremia borneensis in the morning glory family don't track the sun's passage exactly, but they do generally keep blooms facing sunward during the flowering season, say Sandra Patio of the Instituto Humboldt in Bogot, Colombia, and her colleagues. The researchers describe the motion and its ecological effects in the February Oecologia.
The scientists left some flowers alone but modified others by, for example, covering them with grease to prevent cooling by evaporation and mechanically preventing them from facing the sun.
Patio and her colleagues found that the undisturbed flowers maintained the lowest temperatures and were also the preferred blooms for pollinators. The researchers say their data suggest that a flower's temperature depends on both its position and the evap