scholarly journals Ghrelin affects stopover decisions and food intake in a long-distance migrant

2017 ◽  
Vol 114 (8) ◽  
pp. 1946-1951 ◽  
Author(s):  
Wolfgang Goymann ◽  
Sara Lupi ◽  
Hiroyuki Kaiya ◽  
Massimiliano Cardinale ◽  
Leonida Fusani
Keyword(s):  
Food Intake ◽  
Peptide Hormone ◽  
Migratory Behavior ◽  
Migratory Restlessness ◽  
Long Distance ◽  
Stopover Site ◽  
Blood Concentrations ◽  
Timing Of Migration ◽  
Fat Stores ◽  
Sylvia Borin

Billions of birds migrate long distances to either reach breeding areas or to spend the winter at more benign places. On migration, most passerines frequently stop over to rest and replenish their fuel reserves. To date, we know little regarding how they decide that they are ready to continue their journey. What physiological signals tell a bird’s brain that its fuel reserves are sufficient to resume migration? A network of hormones regulates food intake and body mass in vertebrates, including the recently discovered peptide hormone, ghrelin. Here, we show that ghrelin reflects body condition and influences migratory behavior of wild birds. We measured ghrelin levels of wild garden warblers (Sylvia borin) captured at a stopover site. Further, we manipulated blood concentrations of ghrelin to test its effects on food intake and migratory restlessness. We found that acylated ghrelin concentrations of garden warblers with larger fat scores were higher than those of birds without fat stores. Further, injections of unacylated ghrelin decreased food intake and increased migratory restlessness. These results represent experimental evidence that appetite-regulating hormones control migratory behavior. Our study lays a milestone in migration physiology because it provides the missing link between ecologically dependent factors such as condition and timing of migration. In addition, it offers insights in the regulation of the hormonal system controlling food intake and energy stores in vertebrates, whose disruption causes eating disorders and obesity.

scholarly journals Energy Stores, Oxidative Balance, and Sleep in Migratory Garden Warblers (Sylvia borin) and Whitethroats (Sylvia communis) at a Spring Stopover Site

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrea Ferretti ◽  
Scott R McWilliams ◽  
Niels C Rattenborg ◽  
Ivan Maggini ◽  
Massimiliano Cardinale ◽  
...  
Keyword(s):  
Food Intake ◽  
High Energy ◽  
Oxidative Status ◽  
Energy Reserves ◽  
Stopover Site ◽  
Garden Warbler ◽  
Oxidative Balance ◽  
Energy Stores ◽  
Sylvia Borin ◽  
Sylvia Communis

Synopsis Little is known about how songbirds modulate sleep during migratory periods. Due to the alternation of nocturnal endurance flights and diurnal refueling stopovers, sleep is likely to be a major constraint for many migratory passerine species. Sleep may help to increase the endogenous antioxidant capacity that counteracts free radicals produced during endurance flight and reduces energy expenditure. Here, we investigated the relationship between sleep behavior, food intake, and two markers of physiological condition—the amount of energy reserves and oxidative status—in two migratory songbird species, the garden warbler (Sylvia borin) and the whitethroat (Sylvia communis). In garden warblers, birds with high energy stores were more prone to sleep during the day, while this condition-dependent sleep pattern was not present in whitethroats. In both species, birds with low energy stores were more likely to sleep with their head tucked in the feathers during nocturnal sleep. Moreover, we found a positive correlation between food intake and the extent of energy reserves in garden warblers, but not in whitethroats. Finally, we did not find significant correlations between oxidative status and sleep, or oxidative status and energy stores. Despite our study was not comparative, it suggests that different species might use different strategies to manage their energy during stopover and, additionally, it raises the possibility that migrants have evolved physiological adaptations to deal with oxidative damage produced during migration.

scholarly journals Variation in candidate genes CLOCK and ADCYAP1 does not consistently predict differences in migratory behavior in the songbird genus Junco

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 115 ◽  
Author(s):  
Mark P Peterson ◽  
Mikus Abolins-Abols ◽  
Jonathan W Atwell ◽  
Rebecca J Rice ◽  
Borja Milá ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Migratory Behavior ◽  
Migratory Restlessness ◽  
Long Distance ◽  
Captive Populations ◽  
Molecular Genetic Basis ◽  
Allele Length ◽  
Migratory Status

Recent studies exploring the molecular genetic basis for migratory variation in animals have identified polymorphisms in two genes (CLOCK and ADCYAP1) that are linked to circadian rhythms and correlate with migratory propensity and phenology among individuals and populations. Results from these initial studies are mixed, however, and additional data are needed to assess the generality and diversity of the molecular mechanisms that regulate the biology of migration. We sequenced CLOCK and ADCYAP1 in 15 populations across the two species of the avian genus Junco, a North American lineage in which multiple recently diverged subspecies and populations range from sedentary to long-distance migrants. We found no consistent associations between allele length and migratory status across the genus for either CLOCK or ADCYAP1. However, within two subspecies groups, populations that migrate longer distances have longer CLOCK alleles on average. Additionally, there was a positive relationship between ADCYAP1 allele length and migratory restlessness (zugunruhe) among individuals within one of two captive populations studied—a result similar to those reported previously within captive blackcaps (Sylvia atricapilla). We conclude that, while both ADCYAP1 and CLOCK may correlate with migratory propensity within or among certain populations or species, previously identified relationships between migratory behavior and sequence variants cannot be easily generalized across taxa.

scholarly journals Memories of Migrations Past: Sociality and Cognition in Dynamic, Seasonal Environments

2021 ◽  
Vol 9 ◽  
Author(s):  
Eliezer Gurarie ◽  
Sriya Potluri ◽  
George Christopher Cosner ◽  
Robert Stephen Cantrell ◽  
William F. Fagan
Keyword(s):  
Environmental Changes ◽  
Animal Movement ◽  
Spatial Scales ◽  
Rapid Change ◽  
Reference Memory ◽  
Migratory Behavior ◽  
Migration Behavior ◽  
Long Distance ◽  
Trade Offs ◽  
Resource Dynamics

Seasonal migrations are a widespread and broadly successful strategy for animals to exploit periodic and localized resources over large spatial scales. It remains an open and largely case-specific question whether long-distance migrations are resilient to environmental disruptions. High levels of mobility suggest an ability to shift ranges that can confer resilience. On the other hand, a conservative, hard-wired commitment to a risky behavior can be costly if conditions change. Mechanisms that contribute to migration include identification and responsiveness to resources, sociality, and cognitive processes such as spatial memory and learning. Our goal was to explore the extent to which these factors interact not only to maintain a migratory behavior but also to provide resilience against environmental changes. We develop a diffusion-advection model of animal movement in which an endogenous migratory behavior is modified by recent experiences via a memory process, and animals have a social swarming-like behavior over a range of spatial scales. We found that this relatively simple framework was able to adapt to a stable, seasonal resource dynamic under a broad range of parameter values. Furthermore, the model was able to acquire an adaptive migration behavior with time. However, the resilience of the process depended on all the parameters under consideration, with many complex trade-offs. For example, the spatial scale of sociality needed to be large enough to capture changes in the resource, but not so large that the acquired collective information was overly diluted. A long-term reference memory was important for hedging against a highly stochastic process, but a higher weighting of more recent memory was needed for adapting to directional changes in resource phenology. Our model provides a general and versatile framework for exploring the interaction of memory, movement, social and resource dynamics, even as environmental conditions globally are undergoing rapid change.

scholarly journals Migratory orientation in a narrow avian hybrid zone

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3201 ◽  
Author(s):  
David P.L. Toews ◽  
Kira E. Delmore ◽  
Matthew M. Osmond ◽  
Philip D. Taylor ◽  
Darren E. Irwin
Keyword(s):  
Hybrid Zone ◽  
Genetic Background ◽  
Migratory Restlessness ◽  
Long Distance ◽  
Mountain Valley ◽  
Migratory Orientation ◽  
Isotopic Studies ◽  
Migratory Routes ◽  
Species Specific ◽  
Migratory Divide

Background Zones of contact between closely related taxa with divergent migratory routes, termed migratory divides, have been suggested as areas where hybrid offspring may have intermediate and inferior migratory routes, resulting in low fitness of hybrids and thereby promoting speciation. In the Rocky Mountains of Canada there is a narrow hybrid zone between Audubon’s and myrtle warblers that is likely maintained by selection against hybrids. Band recoveries and isotopic studies indicate that this hybrid zone broadly corresponds to the location of a possible migratory divide, with Audubon’s warblers migrating south-southwest and myrtle warblers migrating southeast. We tested a key prediction of the migratory divide hypothesis: that genetic background would be predictive of migratory orientation among warblers in the center of the hybrid zone. Methods We recorded fall migratory orientation of wild-caught migrating warblers in the center of the hybrid zone as measured by video-based monitoring of migratory restlessness in circular orientation chambers. We then tested whether there was a relationship between migratory orientation and genetic background, as measured using a set of species-specific diagnostic genetic markers. Results We did not detect a significant association between orientation and genetic background. There was large variation among individuals in orientation direction. Mean orientation was towards the NE, surprising for birds on fall migration, but aligned with the mountain valley in which the study took place. Conclusions Only one other study has directly analyzed migratory orientation among naturally-produced hybrids in a migratory divide. While the other study showed an association between genetic background and orientation, we did not observe such an association in yellow-rumped warblers. We discuss possible reasons, including the possibility of a lack of a strong migratory divide in this hybrid zone and/or methodological limitations that may have prevented accurate measurements of long-distance migratory orientation.

Post-partum blood leptin concentrations and energy balance in first calving dairy heifers

2002 ◽  
Vol 2002 ◽  
pp. 91-91
Author(s):  
A.R.G. Wylie ◽  
D.J. Devlin ◽  
T.W.J. Keady ◽  
C.S. Mayne ◽  
R.E. Agnew ◽  
...  
Keyword(s):  
Energy Balance ◽  
Post Partum ◽  
Reproductive Activity ◽  
Negative Energy ◽  
Energy Output ◽  
Ovarian Activity ◽  
Blood Concentrations ◽  
Dairy Heifers ◽  
Gnrh Release ◽  
Fat Stores

Blood concentrations of leptin, the first of several recently-discovered adipocyte proteins, putatively signal the extent of fat energy reserves to the hypothalamus in mammals and help regulate food intake and reproductive activity (through control of GnRH release). In early post-partum dairy cows, the rapidly increasing milk energy output and slowly increasing feed energy intake produce a negative energy balance (-ve EB) that is met by mobilisation of adipose fat stores and the severity and/or duration of the –ve EB may delay resumption of normal ovarian activity. The objective of the current study was to compare post-partum EB and serum leptin concentration profiles in Holstein-Friesian and Norwegian Red heifers, both of high genetic merit within their breed.

scholarly journals Increased Stopover Duration and Low Body Condition of the Pied Flycatcher (Ficedula hypoleuca) at an Autumn Stopover Site

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2208
Author(s):  
Bernice Goffin ◽  
Marcial Felgueiras ◽  
Anouschka R. Hof
Keyword(s):  
Environmental Change ◽  
Body Condition ◽  
Environmental Conditions ◽  
Ficedula Hypoleuca ◽  
Autumn Migration ◽  
Long Distance ◽  
Stopover Site ◽  
Stopover Duration ◽  
Stopover Sites ◽  
Over Time

Many long-distance migratory bird species are in decline, of which environmental changes, such as climate change and land-use changes, are thought to be important drivers. The effects of environmental change on the migration of these birds have often been studied during spring migration. Fewer studies have explored the impacts of environmental change on autumn migration, especially at stopover sites. However, stopover sites are important, as the quality of these sites is expected to change over time. We investigated impacts of local environmental conditions on the migration strategy and body condition of the Pied Flycatcher (Ficedula hypoleuca) at an autumn migration stopover site using long-term ringing data (1996–2018) and local environmental conditions. We found that although the arrival and departure dates of birds at the stopover site remained unchanged, the body condition (fat score) of the individuals caught decreased, and the stopover duration increased. This suggests that conditions at the stopover site during the autumn migration period have deteriorated over time. This study emphasizes the importance of suitable stopover sites for migratory birds and stresses that changes in environmental conditions during the autumn migration period may be contributing to the current decline in long-distance migratory passerines.

Migratory behaviour of captive white-crowned sparrows, Zonotrichia leucophrys gambelii, differs during autumn and spring migration

Behaviour ◽  
2006 ◽  
Vol 143 (10) ◽  
pp. 1219-1240 ◽  
Author(s):  
Marilyn Ramenofsky ◽  
Renée Agatsuma
Keyword(s):  
Life History ◽  
High Intensity ◽  
Primary Source ◽  
Migratory Restlessness ◽  
Long Distance ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
Life History Stages ◽  
In Captivity ◽  
Zonotrichia Leucophrys Gambelii

AbstractGambel's white-crown sparrow (Zonotorichia leucophrys gambelii) is a long-distance, over-land migrant. In captivity birds display many characteristics of the autumn and spring migratory life history stages that include hyperphagia, fattening and high intensity nocturnal activity termed migratory restlessness or Zugunruhe. We recorded the behaviour of captive birds while simultaneously collecting 24 h locomotor activity. These data were used to define the behaviour displayed by captive birds during autumn and spring in order to compare the two migratory stages and to draw inferences for free-living birds. The predominant behaviour during day and nighttime was rest. Feeding occurred only during daylight hours but at a greater frequency in autumn than spring. Birds generally used their feet as the primary source of locomotion during the day termed 'jump'. During the night, two distinct behaviours, 'beak-up flight' and 'beak-up' involving high intensity wing motions were observed and considered components of migratory restlessness. The frequency of the 'beak-up flight' was greatest during spring and associated with the enhanced tempo of vernal migration. In both stages, migratory restlessness was preceded by a quiescent phase, the occurrence of which differed and related to time available for foraging and length of the night. Given these findings, we hypothesize that diel behaviours displayed by autumn and spring migrants in captivity highlight distinctions between the two life history stages.

Regulation of food intake by metabolic fuels in white-crowned sparrows

1995 ◽  
Vol 269 (6) ◽  
pp. R1462-R1468 ◽  
Author(s):  
T. Boswell ◽  
R. D. Richardson ◽  
R. J. Seeley ◽  
M. Ramenofsky ◽  
J. C. Wingfield ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Food Intake ◽  
Carbohydrate Metabolism ◽  
Plasma Lipids ◽  
Migratory Birds ◽  
Low Doses ◽  
Fatty Acid Utilization ◽  
Increase Food Intake ◽  
Fat Stores ◽  
Higher Doses

Migratory birds rely on increased fat storage and fatty acid utilization to meet seasonal changes of energy expenditure and as a result increase food intake and fat stores before migration. To determine whether their feeding behavior is sensitive to carbohydrate and/or fatty acid utilization, white-crowned sparrows maintained on short daylength (9L15D) were injected intraperitoneally with 2-deoxy-D-glucose (2-DG) or 2,5-anhydro-D-mannitol (2,5-AM). Low doses of 2-DG (25 or 50 mg/kg) had no effect on food intake, and higher doses (100 or 300 mg/kg) significantly suppressed feeding after 1 and 2 h. No dose of 2-DG increased meal size. Similarly, low doses of 2,5-AM (25, 50, or 100 mg/kg) had no effect on food intake, and higher doses (300 and 600 mg/kg) significantly suppressed intake. These data suggest that decreased carbohydrate metabolism does not elicit feeding in this species. Importantly, these drugs, as well as insulin and glucagon, were demonstrated to increase plasma fatty acids as well as to decrease feeding. Injections of tributyrin (100, 300, 600, or 2,000 mg/kg i.p.) or glycerol (300, 450, and 600 mg/kg) also significantly suppressed 60-min and 120-min food intake dose dependently in these birds, and equimolar glucose (1,200 mg/kg) had no effect. We conclude that feeding by the white-crowned sparrow is unresponsive to manipulations of carbohydrate metabolism and is decreased after manipulations that increase plasma lipids.

Actions of amylin on subfornical organ neurons and on drinking behavior in rats

1999 ◽  
Vol 276 (2) ◽  
pp. R514-R521 ◽  
Author(s):  
Thomas Riediger ◽  
Matthias Rauch ◽  
Herbert A. Schmid
Keyword(s):  
Food Intake ◽  
Drinking Behavior ◽  
Peptide Hormone ◽  
Subfornical Organ ◽  
Threshold Concentration ◽  
Ang Ii ◽  
Excitatory Effect ◽  
Nutrient Influx ◽  
And Storage

Amylin, a peptide hormone secreted by pancreatic β-cells after food intake, contributes to metabolic control by regulating nutrient influx into the blood, whereas insulin promotes nutrient efflux and storage. We now report that amylin activates neurons in the subfornical organ (SFO), a structure in which the lack of a functional blood-brain barrier and the presence of a high density of amylin receptors may render it accessible and sensitive to circulating amylin. In an in vitro slice preparation of the rat SFO, 73% of 78 neurons were excited by superfusion with rat amylin (10−8–10−7M); the remainder were insensitive. The threshold concentration for the excitatory response of amylin was <10−8 M and thus similar in potency to a previously reported excitatory effect of ANG II on the same neurons. The excitatory effect of amylin was completely blocked by coapplication of the selective amylin receptor antagonist AC-187 (10−6–10−5M) but was not affected by losartan (10−5 M). Subcutaneous injections of 40 nmol of amylin significantly increased water intake in euhydrated rats, as did an equimolar dose of ANG II, which is a well-described SFO-mediated effect of circulating ANG II. These results point to the SFO as a sensory central nervous target for amylin released systemically in response to metabolic changes. Furthermore, we suggest that amylin release during food intake may stimulate prandial drinking.

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