Elliott Chaparral Reserve

01 Apr, 01 AM - 01 Jul, 10 AM

We are interested in the factors maintaining a spatially discrete flower color polymorphism in southern California populations of Mimulus aurantiacus. Coastal populations contain exclusively red flowers, while approximately 30 km from the coast, there is an abrupt transition to plants with only yellow flowers. Preliminary molecular genetic data suggest little evidence of historical isolation between the forms, implying instead that strong spatially variable natural selection may be responsible for the maintenance of this polymorphism. One potential selective force may be due to the differential preferences of animal pollinators for each floral type in each region. Therefore, we propose to create an experimental population of red and yellow flowered individuals on the reserve to measure pollinator-mediated selection. Specifically, we plan to transport 60 potted plants (30 of each flower color) to three coastal and three inland regions, and monitor pollinator visitation to these plants. The reserve will serve as one of the thee coastal sites. The prediction would be that red-flowered plants receive an increase in overall visitation within coastal regions, while yellow-flowered plants receive higher visitation inland. The plants will be arranged in a random order, and will remain in their pots (they will not be transplanted into the ground). They will be placed on the ground, at least 200m from the nearest natural Mimulus population. They will be watered in their pots as needed (approximately every 2 days). Although we propose to introduce non-native genotypes, and the possibility does exist for some non-native pollen to escape, we feel that the overall impact on the reserve should be minimal. Not only will the plants be located far enough away from naturally occurring plants, but the small number of flowers per plant (approximately 20-30), and the limited overall visitation seen in natural populations, make the potential for unintended gene flow limited. Pollinator flying distances are also restricted enough that limited opportunity exists for pollen escape. We will conduct the experiment during different parts of the day (pre-dawn to post-dusk) for a two week period twice during the season. As a result of the long hours that will be required to monitor this experimental population, occasional overnight use may be required. This experiment will help us to identify the form of selection that is operating to maintain a dramatic flower color polymorphism, and we feel that the use of this reserve is critical for its successful completion.

Visit #1065 @Elliott Chaparral Reserve

Approved

Under Project # 906 | Research

University of California San Diego - Biology

faculty - University of Oregon

Reservation Members(s)

Matt Streisfeld Apr 1 - Jul 1, 2003 (92 days)
Group of 4 Undergraduate Student Apr 1 - Jul 1, 2003 (92 days)

Reserve Resources(s) | Create Invoice

Grounds use only 5 Apr 1 - Jul 1, 2003