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Hormones mediate physiological and behavioral changes in adults as they transition into reproduction. In this study, we characterize the circulating levels of five key hormones involved in reproduction in rock doves ( Columba livia ): corticosterone, progesterone, estradiol, testosterone, and prolactin using univariate and multivariate approaches. We show similar patterns as previous studies in the overall patterns in circulating levels of these hormones, i.e., testosterone (males) and estradiol (females) high during nest-building or egg-laying, prolactin increasing at mid-incubation and peaking at hatching (both sexes), and elevated corticosterone levels in later incubation and early nestling development. In our investigation of hormone co-variation, we find a strong correlation between prolactin and corticosterone across sampling stages and similarities in earlier (early to mid-incubation) compared to later (late incubation to nestling d9) sampling stages in males and females. Finally, we utilized experimental manipulations to simulate nest loss or altered caregiving lengths to test whether external cues, internal timing, or a combination of these factors contributed most to hormone variation. Following nest loss, we found that both males and females responded to the external cue. Males generally responded quickly following nest loss by increasing circulating testosterone, but this response was muted when nest loss occurred early in reproduction. Similar treatment type, e.g., removal of eggs, clustered similarly in hormone space. These results suggest internal drivers limited male response early in reproduction to nest loss. In contrast, circulating levels of these hormones in females either did not change or decreased following nest manipulation suggesting responsiveness to external drivers, but unlike males, this result suggests that reproductive processes were decreasing.
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This content will become publicly available on December 1, 2025
Determining homing abilities of nesting male threespine stickleback ( Gasterosteus aculeatus )
Homing behavior allows individuals to return to a home site when displaced, presumably increasing fitness by increasing access to known food resources, refuges from predators, and breeding opportunities. Homing has been demonstrated in Gasterosteus aculeatus, also known as the threespine stickleback. We hypothesized that because stickleback males guard a nest and tend to the eggs and fry, they should be particularly incentivized to home. In an experiment, we marked and displaced nesting male stickleback over a variety of distances to see how far they were able to home and whether homing success declined with distance displaced. We found that stickleback males did home, which is consistent with other studies. Additionally, we found that the return probability decreased with distance displaced, though not significantly. However, some nests were clearly occupied by new, unmarked males after displacement, meaning that even if an experimentally displaced fish returned, they might not have been able to regain their nest. Removing these cases from the data strengthened the expected negative relationship between distance and return, suggesting that stickleback use landmark cues to navigate home.
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- Award ID(s):
- 2145830
- PAR ID:
- 10565904
- Editor(s):
- NA
- Publisher / Repository:
- BioOne Complete
- Date Published:
- Journal Name:
- BIOS
- Edition / Version:
- NA
- Volume:
- 95
- Issue:
- 4
- ISSN:
- 0005-3155
- Page Range / eLocation ID:
- 246-250
- Subject(s) / Keyword(s):
- Site fidelity Landmark recognition Priority effect
- Format(s):
- Medium: X Size: NA Other: NA
- Size(s):
- NA
- Sponsoring Org:
- National Science Foundation
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