Abstract Detail

Pollination Biology

Castilla, Antonio R [1], Rodriguez, Maria Fabiola [1], O'Connell, Megan [1], Pope, Nathaniel [1], Trevino, Laurel [1], Santos, Alonso [2], Jha, Shalene [1].

Adding gene flow and landscape to the pollinator performance concept.

The evolutionary rationale for the existence of pollinator syndromes centers on the idea that different pollinator species differ in their ability to successfully pollinate flowers. Pollinators may differ not only quantitatively, in terms of fruit and seed set, but also qualitatively in terms of the genetic composition of the plant’s offspring. This is especially critical given that many plant species exhibit inbreeding depression and high fine-scale spatial genetic structuring in their populations. Given that nearly 5.8 million ha of tropical forest are deforested per year, there is great need to identify which pollinator species are most vulnerable to habitat change, and what the independent contributions of each pollinator species is for the maintenance of reproductive processes and genetic diversity for tropical trees. We conducted a single visit experiment in three populations of the understory tree Miconia affinis in Panama. In each population, we randomly chose 30 trees and bagged five randomly chosen inflorescences per tree. The bagged inflorescences were exposed to a single insect visitor, which was subsequently caught and identified. The fruits were allowed to develop to maturity and collected. We compared different pollinator species in terms of success in setting fruits, the number of viable seeds per fruit, and pollen dispersal distances estimated by a microsatellite-based population genetic analysis. Specifically, a total of 532 seeds were screened at 8 polymorphic loci to determine sire identity and assess pollinator dispersal ability. Twenty different bee species visited M. affinis’ flowers. These species differ widely in their size with the intertegular distance ranging from 0.91 to 7.72 mm. Our results indicate that pollinator species differed significantly in their individual contribution to plant reproduction. Flowers visited by large bees set more fruits. Large bees also produced higher proportions of viable seeds per fruit than smaller-bodied species. Our results also reveal that the ability to disperse pollen long distances is not related to the pollinator size, which highlight the critical role of the whole pollinator community maintaining the genetic connectivity in tropical tree populations. Given the prevalence of genetic structuring and inbreeding depression in plant populations, we posit that assessments of pollinator quality should consider not only seed set numbers, but also the pollinator’s ability to promote genetic diversity in plant’s offspring.

1 - University of Texas at Austin, 1 University Station, Biological Laboratories C0930, Austin, TX, 78712, United States
2 - University of Panama, Facultad de Ciencias Naturales Exactas y Tecnolo, Zoology, 0824-00021, Panama City, Panamá , Panama City, Panama, Panama

Keywords:
long-distance dispersal
bees
Local kinship
Conspecific density
Seed abortion
Fruit set
Panama.

Presentation Type: Oral Paper
Session: 36, Pollination Biology
Location: 203/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 11:30 AM
Number: 36013
Abstract ID:902
Candidate for Awards:None