PARENT SESSION
Contributed Oral Session 63: Plant Genetics: Population Level Implications
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 519 A, Level 5, Palais des congrès de Montréal
Pollen mediated gene dispersal in Mimulus ringens: Pollinator grooming and multiple flower displays.
Holmquist, Karsten*,1, Karron, Jeffrey1, Mitchell, Randall2, 1 University of Wisconsin Milwaukee, Milwaukee, WI, EEUU2 University of Akron, Akron, OH, EEUU
ABSTRACT- Pollen foraging bumble bees frequently groom pollen from their bodies and transfer it to specialized pollen-carrying structures (scopae or corbiculae). Grooming makes large portions of the pollen load unavailable for deposition onto recipient stigmas and therefore reduces pollen carryover. However, bumble bees may be more likely to groom during transitions between plants than during transitions between flowers within a plant. If pollen from several successively visited flowers within a single plant's floral display accumulates in layers, grooming may re-expose buried pollen grains and increase pollen carryover. We report patterns of bumble bee grooming, and the resulting patterns of pollen-mediated gene dispersal in linear arrays of Mimulus ringens plants, each with four open flowers. We contrast these findings to patterns of pollinator grooming and pollen-mediated gene dispersal when bumble bees forage in linear arrays of M. ringens plants with a single open flower. When plants display only one open flower, pollinators groom to some extent after every flower visited. Pollen dispersal is very limited with approximately 95% of the pollen and genes distributed over the first four recipient flowers. Pollen dispersal curves and paternity shadows decay at a faster than exponential rate due to the effects of intensive pollinator grooming. However, when plants display four open flowers, pollinators are less likely to groom during transitions between flowers within the display. Therefore, pollen from flowers visited earlier in the display becomes buried. As the pollinator grooms intensively during transitions between plants, buried pollen is re-exposed so that the pollen dispersal curve has a longer-than-exponential tail. As a result of patterns of pollinator grooming in response to the floral display, the flowers within the display interact so that pollen mediated gene dispersal is significantly extended when compared to displays of single open flowers.
Key words: bombus, monkeyflower, pollen dispersal, pollen-mediated gene dispersal