| Title: |
Carry-Over Effects and Plumage Polymorphism in Swainson's Hawks |
| Authors: |
Briggs, Christopher W. |
| Contributors: |
Collopy, Michael W.; Forister, Matthew; Provosudov, Vladimir; Sedinger, James; Poulson, Simon |
| Publication Year: |
2018 |
| Collection: |
University of Nevada, Reno: ScholarWorks Repository |
| Subject Terms: |
apostatic selection; heterozygous advantage; mate choice; melanism; ptilochronology; seasonal interactions |
| Description: |
The maintenance of genetic diversity in the face of forces such as genetic drift and natural selection has intrigued scientists for decades. Such processes should seemingly oppose diversity in a stable environment. However, environments are rarely stable in natural systems and processes can be complex. We investigate how a plumage polymorphism is maintained in a population of Swainson's Hawks (Buteo swainsoni) in northern California, USA. Swainson's Hawks are highly polymorphic in the belly, flanks and underwing coverts ranging from white to dark brown and seemingly everything in between. Generally, these morphs can be grouped into 3 general classes; light, intermediate and dark. We first examined potential fitness differences among morph classes. Specifically we examined two primary hypotheses of heterosis (i.e., heterozygote advantage) and apostatic (i.e., frequency dependant) selection. Both mechanisms have been cited before in predator populations as potential mechanisms to maintain a polymorphism. However, we found no evidence of differences in any fitness parameter between the morph classes including; nest success, nest productivity, recruitment of offspring or lifetime reproductive success. There was marginal evidence of differences in survival between morph classes with dark individuals having a slightly higher adult survival compared to intermediate and dark morph. We also examined sexual selection in this population. Individuals did not appear to mate assortatively (i.e. there was no preference for a mate based on one's own mate class). For females, there was similarly no evidence for imprinting. In contrast, males chose mates that consistently matched the maternal morph. Further, males selected mates more consistently than we expect by chance. Finally, males that were not able to select mates with the same morph class as their mother had a lower lifetime reproductive success. This result indicates that these males may not have invested as heavily in reproduction, or were lower quality males that could ... |
| Document Type: |
doctoral or postdoctoral thesis |
| File Description: |
PDF |
| Language: |
unknown |
| Relation: |
http://hdl.handle.net/11714/3878 |
| Availability: |
http://hdl.handle.net/11714/3878 |
| Rights: |
In Copyright(All Rights Reserved) ; Author(s) |
| Accession Number: |
edsbas.456C4D0 |
| Database: |
BASE |