Rescue of stranded pollen grains by secondary transfer

Secondary transfer of pollen can occur when a second pollinator remobilizes grains that had already been transferred to a flower by a previous pollinator. We used a pollen‐color dimorphism to measure components of secondary transfer by bumble bees visiting the lily Erythronium grandiflorum . Remobilization was surprisingly high, ranging from 20% of grains deposited on stigmas to 90% of grains deposited on inner tepal surfaces. Because most of the grains that are remobilized would otherwise have been stranded on non‐stigmatic surfaces, secondary transfer has the beneficial effect of returning lost grains to circulation.