Related Experiment Video
Updated: Mar 6, 2026

In Vitro Rearing of Solitary Bees: A Tool for Assessing Larval Risk Factors
Published on: July 16, 2018
The effects of pollen composition on fitness components in a neotropical herb
Douglas W Schemske1, Lynn P Pautler2
1Department of Biology, University of Chicago, 60637, Chicago, IL, USA.
Abstract:
Experimental pollinations of Costus allenii (Zingiberaceae) were conducted to assess the effects of pollen composition on fitness. Plants were selfed, outcrossed with the first nearest neighbor, and outcrossed with pollen mixtures obtained from the nearest 2, 3, and 5 plants. Cross type had a significant effect on seed production, seed weight and total-plant dry weight. Progeny from crosses with 3, and 5 parents grew significantly larger than selfed progeny, or those from 1-parent crosses. Competition experiments indicated the superiority of progeny from 3-, and 5-parent crosses over progeny from 1-parent crosses, but no differences in competitive ability were observed between progeny from 3-, and 5-parent crosses. Relative fitness, based on 1) seed production, 2) percent germination, and 3) dry weight, varied significantly among crosses, and was greatest for crosses with 3 parents and lowest for selfs. The relative fitness of progeny from 5-parent crosses was lower than that of all other outcrossed classes. We suggest that the significant effect of pollen composition on fitness results from variation in the genetic similarity of seed and pollen parents, which is a function of spatial distribution and population structure.
Related Concept Videos
Pollination and Flower Structure
Frequency-dependent Selection
Genetics of Speciation
Inclusive Fitness
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Mutation, Gene Flow, and Genetic Drift

