Találati lista | Tudóstér

001-es BibID:	BIBFORM107672
035-os BibID:	(WoS)000368560000005 (Scopus)84957921974
Első szerző:	Krause, Jesse S.
Cím:	Annual Hematocrit Profiles in Two Subspecies of White-Crowned Sparrow : A Migrant and a Resident Comparison / Jesse S. Krause, Zoltán Németh, Jonathan H. Pérez, Helen E. Chmura, Marilyn Ramenofsky, John C. Wingfield
Dátum:	2016
ISSN:	1522-2152
Megjegyzések:	Hematocrit is an easily measured parameter that can be used to assess changes in oxygen carrying capacity necessitated by fluctuations in metabolic demands. Most hematocrit studies draw conclusions from changes in hematocrit that occur over a small sampling interval without an understanding of the variation that exists across the annual cycle. White-crowned sparrows provide an excellent model system due to the existence of a resident subspecies (Zonotrichia leucophrys nuttalli) that serves as a natural control for a migrant subspecies (Zonotrichia leucophrys gambelii). Comparing these two subspecies allows for the investigation of adaptive physiological changes at each life-history stage (i.e., migration, breeding, molt, etc.) in response to changing metabolic demands. Of particular interest, this subspecies comparison, by both calendar month and lifehistory stage, allows for the separation of adaptive increases in hematocrit due to migration fromthe natural seasonal variation in hematocrit. Hematocrit levels for males and females ranged throughout the year between 42%?47% and 40%?47% in the resident and between 45%?58% and 45%?56% in the migrant. In both subspecies, hematocrit levels were elevated during the breeding season compared to the nonbreeding season, and levels were reduced in females during egg laying. When grouped by life-history stage, hematocrit levels were always higher in the migrant compared to the resident. During the months in which migration occurred, hematocrit levels were 10%?12% higher in the migrant compared to the resident subspecies. These data suggest differential regulation of hematocrit between the two subspecies that may be attributed to phenotypic plasticity or genetic differences.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk life-history stage migration, molt breeding biology red blood cells annual cycle
Megjelenés:	Physiological And Biochemical Zoology. - 89 : 1 (2016), p. 51-60. -
További szerzők:	Németh Zoltán (1976-) (biológus) Pérez, Jonathan H. Chmura, Helen E. Ramenofsky, Marilyn Wingfield, John C.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM107062
035-os BibID:	(WoS)000612128700018 (Scopus)85096396692
Első szerző:	Krause, Jesse S.
Cím:	Annual regulation of adrenocortical function in migrant and resident subspecies of white-crowned sparrow / Jesse S. Krause, Zoltán Németh, Jonathan H. Pérez, Helen E. Chmura, Karen R. Word, Hannah J. Lau, Ryan E. Swanson, Jeffrey C. Cheah, Lisa N. Quach, Simone L. Meddle, John C. Wingfield, Marilyn Ramenofsky
Dátum:	2021
ISSN:	0018-506X
Megjegyzések:	Corticosterone affects physiology and behavior both during normal daily processes but also in response to environmental challenges and is known to mediate life history trade-offs. Many studies have investigated patterns of corticosterone production at targeted times of year, while ignoring underlying annual profiles. We aimed to understand the annual regulation of hypothalamic-pituitary-adrenal (HPA) axis function of both migrant (Zonotrichia leucophrys gambelii; n = 926) and resident (Z. l. nutalli; n = 688) subspecies of white-crowned sparrow and how it is influenced by environmental conditions wind, precipitation, and temperature. We predicted that more dramatic seasonal changes in baseline and stress-induced corticosterone would occur in migrants to precisely time the onset of breeding and cope with environmental extremes on their arctic breeding grounds, while changes in residents would be muted as they experience a more forgiving breeding schedule and comparatively benign environmental conditions in coastal California. During the course of a year, the harshest conditions were experienced the summer breeding grounds for migrants, at which point they had higher corticosterone levels compared to residents. For residents, the winter months coincided with harshest conditions at which point they had higher corticosterone levels than migrants. For both subspecies, corticosterone tended to rise as environmental conditions became colder and windier. We found that the annual maxima in stress-induced corticosterone occurred prior to egg lay for all birds except resident females. Migrants had much higher baseline and acute stress-induced corticosterone during breeding compared to residents; where in a harsher environment the timing of the onset of reproduction is more critical because the breeding season is shorter. Interestingly, molt was the only stage within the annual cycle in which subspecies differences were absent suggesting that a requisite reduction in corticosterone may have to be met for feather growth. These data suggest that modulation of the HPA axis is largely driven by environmental factors, social cues, and their potential interactions with a genetic program.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Stress Hypothalamic pituitary adrenal (HPA) axis Life history stage Subspecies Corticosterone Restrain Latitude Breeding season
Megjelenés:	Hormones And Behavior. - 127 : 104884 (2021), p. 1-9. -
További szerzők:	Németh Zoltán (1976-) (biológus) Pérez, Jonathan H. Chmura, Helen E. Word, Karen R. Lau, Hannah J. Swanson, Ryan E. Cheah, Jeffrey C. Quach, Lisa N. Meddle, Simone L. Wingfield, John C. Ramenofsky, Marilyn
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM081984
Első szerző:	Wingfield, John C.
Cím:	A mechanistic approach to understanding range shifts in a changing world : What makes a pioneer? / J. C. Wingfield, J. S. Krause, J. H. Perez, H. E. Chmura, Z. Németh, K. R. Word, R. M. Calisi, S. L. Meddle
Dátum:	2015
ISSN:	0016-6480
Megjegyzések:	A species' range can be thought of as a manifestation of the ecological niche in space. Within a niche, evo-lution has resulted in traits that maximize fitness. Across millennia, natural oscillations in temperaturehave caused shifts in the geographic location of appropriate habitat and with corresponding changesin species' ranges. Contemporary climate change and human disturbance may lead to rapid range expan-sion or contractions with largely unknown consequences. Birds provide an excellent case study of thisphenomenon with some taxa expanding range and others contracting even to the point of extinction.What leads some populations to expand while others contract? Are there physiological and behavioralattributes of ♭♭pioneers" at the forefront of a range shift/expansion?The concept of allostasis provides a framework with which to begin to evaluate when a species will beable to successfully expand into new habitat. This tool allows the integration of normal energeticdemands (e.g. wear and tear of daily and seasonal routines) with novel challenges posed by unfamiliarand human altered environments. Allostasis is particularly attractive because it allows assessment ofhow individual phenotypes may respond differentially to changing environments. Here, we use allostasisto evaluate what characteristics of individuals and their environment permit successful range expansion.Understanding variation in the regulatory mechanisms that influence response to a novel environmentwill be fundamental for understanding the phenotypes of pioneers.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk climate change Invasive species Range expansion Stress Glucocorticoids Allostasis
Megjelenés:	General And Comparative Endocrinology. - 222 (2015), p. 44-53. -
További szerzők:	Krause, J. S. Perez, Jonathan H. Chmura, Helen E. Németh Zoltán (1976-) (biológus) Word, Karen R. Calisi, Rebecca M. Meddle, Simone L.
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: