FRIDAY, Oct. 5 (HealthDay News) -- Primitive plants called cycads use heat and scent to manipulate pollinating insects, a new study reveals.

Cycads, a group of plants that has been around for 250 million to 290 million years, look similar to ferns or palms but are not related to them. Cycads are gymnosperms, a group that also includes modern coniferous tress such as pines and firs.

Reporting in the Oct. 5 issue of Science, a team at the University of Utah has discovered that the plants heat up and emit an intense odor in order to evict thrips (small flying insects) that have been feeding on pollen found in male cycad cones.

The plants then release a milder odor to attract the pollen-covered thrips into their female cones in order to achieve pollination.

This unusual approach may represent an intermediate stage in the evolution of plant pollination, the researchers said.

"People think of plants as just sitting there and looking pretty and sending out some odors to attract pollinators, but these cycads have a specific sexual behavior tuned to repel, attract and deceive the thrips that pollinate them," principal author Irene Terry, research associate professor of biology, said in a prepared statement.

More information

The University of California Museum of Paleontology has more about cycads.