A U.S. study shows plants with male and bisexual flowers have better reproductive success than do other plants.

One widespread sexual plant strategy that remains an evolutionary enigma is the production of both male and bisexual flowers on the same plant — an event that occurs in approximately 4,000 species.

Evolutionary biologists Mario Vallejo-Marin and Mark Rausher of Duke University used experiments with horsenettle, a common North Carolina weed, to demonstrate male flowers increase not only male, but also female, reproductive success.

Such a benefit, said the researchers, might arise if resources saved by producing smaller male flowers are reallocated to increased seed production; if male flowers are more attractive to pollinators; or if male flowers remove less pollen from pollinators than bisexual flowers — thus increasing the amount of non-self pollen available for fruit-producing flowers.

The mechanism responsible for the “good mothers” in Vallejo-Marin and Rausher’s study has not been determined, but data from an unrelated study indicate the female advantage of producing male flowers is not unique to horsenettle.

The research is reported in the journal American Naturalist.

source : www.sciencedaily.com