Investigating the causes of hatching failure of Eastern Bluebird eggs: A possible role for heat shock proteins
Author
Costa, Hannah G.
Access
This item will be available on: 2025-05-01
Abstract
Eastern Bluebirds (Sialia sialis) studied for 13 years at East Carolina University’s West Research Campus have shown declines in reproductive success via hatching failure in recent years. The purpose of my research is to investigate the underlying cause. Since 2012, the rate of hatching failure has increased. Here, I define hatching failure as any nest that had more than one egg fail to hatch. I calculated the percentage of nests that had more than one egg fail to hatch each year based on a total of 581 nest attempts over 11 years. The annual rate of hatching failure reached 30% in 2017, and has since surpassed 30% three more times. I developed two hypotheses for hatching failure. First, since some birds hatched on site are recruited as breeders, there may be elevated levels of breeder relatedness, and inbreeding depression could explain embryo mortality. Though I found no evidence for incestuous matings at the site, philopatric males (those hatched on site) were overrepresented in the sample of pairs that had at least one nest exhibit hatching failure. Second, high seasonal temperatures in nest boxes during summer may have caused developmental failure. In support of this hypothesis, hatching failure affected many later clutches laid in June and July. To investigate the possibility that the eggs that did not survive were more sensitive to high temperatures, sequence variation in heat shock proteins was investigated. Heat shock proteins are molecular chaperones that become overexpressed in response to heat stress. A subunit of the HSP90α gene was amplified and sequenced to look for sequence differences by comparing failed embryo samples to surviving chicks. DNA was extracted from partially developed embryos collected from unhatched eggs, from blood samples collected from their surviving siblings in the same nests and from a sample of chicks hatched in successful nests. Though inconclusive, I found some evidence of an allele corresponding to survival differences. Sequencing genes for heat shock proteins is a step toward looking at possible modifiers of gene expression such as DNA methylation, which is possibly mediated through the philopatric paternal lines. This is among the first studies to investigate the role of heat shock proteins in a wild songbird.
Date
2023-05-03
Citation:
APA:
Costa, Hannah G..
(May 2023).
Investigating the causes of hatching failure of Eastern Bluebird eggs: A possible role for heat shock proteins
(Honors Thesis, East Carolina University). Retrieved from the Scholarship.
(http://hdl.handle.net/10342/13076.)
MLA:
Costa, Hannah G..
Investigating the causes of hatching failure of Eastern Bluebird eggs: A possible role for heat shock proteins.
Honors Thesis. East Carolina University,
May 2023. The Scholarship.
http://hdl.handle.net/10342/13076.
May 16, 2024.
Chicago:
Costa, Hannah G.,
“Investigating the causes of hatching failure of Eastern Bluebird eggs: A possible role for heat shock proteins”
(Honors Thesis., East Carolina University,
May 2023).
AMA:
Costa, Hannah G..
Investigating the causes of hatching failure of Eastern Bluebird eggs: A possible role for heat shock proteins
[Honors Thesis]. Greenville, NC: East Carolina University;
May 2023.
Collections
Publisher
East Carolina University