The tendency of some flowers to be ‘honest’ and reward pollinators with nectar is partly genetic, study suggests

Flowers can produce showy displays that appeal to pollinating insects or animals, but some “cheat” by enticing pollinators but not rewarding them with nectar. Research in New Phytologist indicates that the tendency of flowers to be “honest” and reward pollinators with nectar is partly genetic, meaning that it can be passed down through generations.

In the study, researchers investigated floral honesty in the Mexican endemic Turnera velutina (Passifloraceae), analyzing multiple genetically distinct plants (or clones). They found that honesty is heritable and that bees can discriminate among genotypes based on flower size and sugar content.

Bees showed a preference for visiting more honest flower genotypes with higher sugar content, which in turn benefits the plant by increasing seed production. Therefore, floral honesty may evolve and be maintained through pollinator-mediated selection.

“Intriguingly, most genotypes show some degree of floral dishonesty, implying that cheating plants may outnumber honest ones despite pollinator selection pressure,” said corresponding author Sergio Ramos, Ph.D., from the University of Zurich, in Switzerland.

“This paradox suggests that multiple evolutionary forces may be at play in sustaining floral dishonesty in natural populations, warranting further investigation.”