When a plant endemic to several islands in the Western Pacific Ocean taps the services of a helpful insect, a double-dose of benefits comes its way. The plant is a member of a unique group of plants known as cycads, which produce their seeds in cones rather than within fruits. The insect is a tiny moth currently known to exist only on the islands of Guam and Rota. The insect's primary role is to ensure seed production occurs by pollinating the plants. "But what we have learned is the behavior of the moth also triggers the plants into increased frequency of reproduction," said UOG Professor Thomas Marler.
The research conducted in the Western Pacific Tropical Research Center at the University of Guam breaks new ground because the findings reverse how biologists have viewed one component of the plant-insect partnership, and the results appear in the May issue of the American Journal of Botany. "When each organism in a relationship obtains benefits from the other member of the relationship, the partnership is called a mutualism," said Marler. In mutualisms where an insect provides the service of transporting pollen from plant to plant to facilitate seed production, the plant gives back something that benefits the insect.
With many cycad species, the plant offers their male cones as an insect nursery where eggs are laid and larvae eat the cone tissue. "This service has been portrayed for many cycad species as something the plant sacrifices in order to receive the pollination services from the insect," said Marler. The Guam-based research followed many years of plant behavior to show that when the insects were allowed to use the male cones as nursery facilities, those particular plants produced new cones more quickly in the subsequent months or years. So what was once believed to be a sacrifice by the plant to ensure receipt of a separate benefit from the insect turns out to be a second direct benefit received from the insect.
|Contact: Cathleen Moore-Linn|
University of Guam