By The Light of the Full Moon

The lunar cycle is iconic in cultures the world around. Long before it became part of the human lexicon, ecological systems were syncing up with the Earth's rocky satellite. Everything from corals to moths have honed in on the moon's dominance in the night sky. Even plants utilize its reflective properties. One must only marvel at the bright white blooms of a ghost orchid or a Selenicereus cactus to understand what I am talking about. It's not just angiosperms that are taking advantage of moonlight either. As it turns out, a gymnosperm is also part of the lunar party.

Anyone who is aware of diet fads will have undoubtedly heard of Ephedra. This ancient lineage of gymnosperms is more familiar for the alkaloids that it produces than its ecology but one species is changing that. Ephedra foeminea is native to the Mediterranean and has long baffled ecologist who study it. The odd thing about E. foeminea is that it is one of the few (perhaps the only) gymnosperms alive today that have evolved to be pollinated by insects.

When E. foeminea becomes receptive for pollination, the tips of its cones exude small droplets of a clear fluid. However, with no discernible scent, it is not clear exactly how insects locate the cones. That is, until recently. For years, researcher Catarina Rydin and her students have had trouble timing their field work around when this plant becomes receptive. Unlike some of its relatives, E. foeminea didn't appear to have a set reproductive schedule.

Then in 2014 Rydin realized something. After looking through photos of previous years, she realized that the ones in which the plant was exuding droplets were all taken on clear nights under a full moon. That was it. As it turns out, E. foeminea times its reproductive efforts around the full moon. Why? Its actually quite simple. Without flowers or a scent, E. foeminea needs another way for insects to locate its cones. They key is the liquid. Under the light of a full moon, the droplets cause the plant to sparkle. On a clear night, it would be hard to miss. Insects have no issue tuning in to this light display and thus the plant gets what it needs.

The question of how exactly it syncs up with the lunar cycle is a complete mystery. It has been suggested that perhaps the light reflected by the moon is enough to trigger some sort of light receptive chemical in the plant, however, more work is needed to figure that out. This may also explain why this particular species is found farther away from human settlements. Perhaps light pollution is interfering with E. foeminea reproduction. Until more work is done, this wonderful strategy is still a bit in the dark.

Photo Credits: Kristina Bolinder (http://rydingroup.com/kristina-bolinder/) and http://www.west-crete.com

Further Reading:
http://rsbl.royalsocietypublishing.org/content/11/4/20140993

http://www.iucnredlist.org/details/201710/0