A nifty article about cycad pollination by thrips in Science today, in which the pollination system of this ancient plant proves to be much more complex than expected. The plants are first attracting, and then repelling, their pollinators.

To make it additionally interesting, the pollinators are thrips, a group of tiny sucking insects. These insects are rarely more than 1mm long, so aren’t the first group that comes to mind when considering dispersal of pollen. Cycads are well known from the fossil record, so this may be a remnant of a time when pollinator choices were fewer. As gymnosperms, Cycads evolved well before the big angiosperm/insect explosion during the Cretaceous period.

How does it work? Male (pollen producing) cones produce low concentrations of an attractive odor–but only for a little while. Then, they get hot and smelly:

“The insects were attracted to low concentrations of the cycad cone odor but repelled by high concentrations, which actually proved toxic to the thrips. Female cones emit these low concentrations. Come afternoon at certain times of the year, thrips flee their usual digs in male cones and are subsequently lured to female cones, at least temporarily, Terry’s group reports in the 5 October issue of Science. “

A pretty nifty system!

BTW, the full citation:

Odor-Mediated Push-Pull Pollination in Cycads. Irene Terry et al. Science 2007: Vol. 318. no. 5847, p. 70.

Posted by Gwen Pearson

Writer. Nerd. Insect Evangelist. Have you heard the good news? BUGS!