ORCID Profile
0000-0002-3491-5642
Current Organisation
Oregon State University
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Publisher: University of Chicago Press
Date: 12-2014
DOI: 10.1086/678398
Abstract: Climate change, habitat alteration, range expansions, and biological invasions are all predicted to require rapid shifts in multiple traits including behavior and life history, both for initial population establishment and subsequent adaptation. Hormonal mechanisms likely play a key role in facilitating or constraining plastic and genetic responses for suites of traits, but few studies have evaluated their role in shaping contemporary adaptation or ersification. We examined multiple phenotypic adjustments and associated hormonal changes following a recent (early 1980s) colonization event, in which a temperate-breeding songbird, the dark-eyed junco (Junco hyemalis), became established in the Mediterranean climate of San Diego, California. The milder climate has led to an extended breeding season and year-round residency, and we document shifts in multiple sexually selected behaviors and plumage traits. Testosterone titers in San Diego were elevated for longer but with a lower peak value compared to a nearby native-range population, and correlations between testosterone and related traits were similar within and among populations. A common garden study indicated that changes in testosterone likely represent plastic responses to the less seasonal environment of the city, providing the context against which subsequent genetic changes in morphology likely occurred. We argue that correlated shifts in multiple traits, organized by underlying physiology, may be a generally important element of many successful adjustments to changing environments.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Oxford University Press (OUP)
Date: 2012
Abstract: Novel or changing environments expose animals to erse stressors that likely require coordinated hormonal and behavioral adaptations. Predicted adaptations to urban environments include attenuated physiological responses to stressors and bolder exploratory behaviors, but few studies to date have evaluated the impact of urban life on co ergence of these hormonal and behavioral traits in natural systems. Here, we demonstrate rapid adaptive shifts in both stress physiology and correlated boldness behaviors in a songbird, the dark-eyed junco, following its colonization of a novel urban environment. We compared elevation in corticosterone (CORT) in response to handling and flight initiation distances in birds from a recently established urban population in San Diego, California to birds from a nearby wildland population in the species' ancestral montane breeding range. We also measured CORT and exploratory behavior in birds raised from early life in a captive common garden study. We found persistent population differences for both reduced CORT responses and bolder exploratory behavior in birds from the colonist population, as well as significant negative covariation between maximum CORT and exploratory behavior. Although early developmental effects cannot be ruled out, these results suggest contemporary adaptive evolution of correlated hormonal and behavioral traits associated with colonization of an urban habitat.
Publisher: University of Chicago Press
Date: 02-09-2020
DOI: 10.1086/687520
Abstract: Sexual signals contain information on in idual quality or motivation, and most explanations for their reliability are based on signal costs. A recent suggestion is that signaling mistakes, defined as deviations from typical signal design, provide cues on in idual quality, contributing to reliable communication even when signal design is not costly. We describe several atypical song traits in dark-eyed juncos (Junco hyemalis) that may be mistakes during song production or development and occur in up to 6% of songs. These putative mistakes were more frequent in an urban versus a wildland population, and in iduals differed in their frequency of mistakes. Some atypical signals were more frequent in younger males or were negatively related to paternity success, supporting the hypothesis that fewer mistakes indicate in idual quality. We also discuss unexpected results, such as some atypical signals being more frequent in more ornamented males and in songs with lower performance demands. Song consistency (similarity across syllable renditions) was positively related to male age and paternity success nonetheless, relations with paternity were stronger when looking at the most deviant syllable renditions, suggesting that the perceptual salience of large mistakes may mediate receiver responses to song consistency. Results indicate that signaling mistakes reveal relevant information to play a role in communication.
Location: United States of America
No related grants have been discovered for Danielle Whittaker.