Rapid recovery by fat- and muscle-depleted Blackpoll Warblers following trans-oceanic migration is driven by time-minimization

The Auk ◽  
2021 ◽  
Author(s):  
Nicholas J Bayly ◽  
Kenneth V Rosenberg ◽  
D Ryan Norris ◽  
Philip D Taylor ◽  
Keith A Hobson
Keyword(s):  
Negative Correlation ◽  
Flight Muscle ◽  
Migratory Birds ◽  
Long Distance ◽  
Stopover Duration ◽  
Early Arrival ◽  
Show Evidence ◽  
Time Minimization ◽  
Flight Muscles ◽  
Initial Recovery

Abstract Nonstop endurance flights are a defining characteristic of many long-distance migratory birds, but subsequent recovery phases are not typically distinguished from fueling phases (collectively “stopovers”), despite endurance flights inducing marked physiological changes including flight muscle atrophy and gastrointestinal tract reductions. Here, we hypothesize that recovery requires unique behavioral adaptations, leading to departures from the predictions of optimal migration theory for time-minimizing migrants. We predict that recovering birds will (1) select (moist) food-rich habitats on arrival; (2) have slow initial fueling rates due to decreased gastrointestinal capacity; (3) show a negative correlation between stopover duration and arrival condition instead of a negative correlation with fuel deposition rate (FDR); (4) stopover longer than required to store energy reserves for subsequent flights; and (5) show evidence of rebuilding flight muscles. To test these predictions, we studied Blackpoll Warblers (Setophaga striata) in northern Colombia following trans-oceanic flights >2,250 km. Birds selected dry seasonal habitats, despite the proximity of moist forests, and among 1,227 captured individuals, 14–21% were emaciated and 88% had atrophied flight muscles. We recaptured 74 individuals, revealing net positive mass gains and, contrary to prediction (2), no evidence for slow initial recovery rates. Contrary to prediction (3), stopover duration was only weakly correlated with arrival condition and birds with high FDR (4.9% lean body mass day–1) had shorter durations (3 days) relative to birds with slower rates (7 days): both groups accumulated sufficient fuel to reach nonbreeding (over-wintering) grounds 500–1,000 km away. Mass increases were largely attributable to fat deposition but some birds improved flight muscle condition (31.9%), consistent with prediction (5). Together these results reveal a strong selection for time-minimization in the decisions made by Blackpoll Warblers following trans-oceanic flights, likely mediated through advantages to early arrival on nonbreeding grounds, contrary to our hypothesis of recovery imposing unique selection pressures.

scholarly journals Size and accumulation of fuel reserves at stopover predict nocturnal restlessness in a migratory bird

2013 ◽  
Vol 9 (6) ◽  
pp. 20130712 ◽  
Author(s):  
Cas Eikenaar ◽  
Jan Laszlo Schläfke
Keyword(s):  
Migratory Birds ◽  
Breeding Site ◽  
Migratory Bird ◽  
Migratory Restlessness ◽  
Oenanthe Oenanthe ◽  
Stopover Duration ◽  
Early Arrival ◽  
Fuel Accumulation ◽  
Departure Decisions ◽  
Spring Stopover

Early arrival at the breeding site positively affects the breeding success of migratory birds. During migration, birds spend most of their time at stopovers. Therefore, determining which factors shape stopover duration is essential to our understanding of avian migration. Because the main purpose of stopover is to accumulate fat as fuel for the next flight bout, fuel reserves at arrival and the accumulation of fuel are both expected to affect stopover departure decisions. Here, we determined whether fuel reserves and fuel accumulation predict a bird's motivation to depart, as quantified by nocturnal migratory restlessness (Zugunruhe), using northern wheatears ( Oenanthe oenanthe ) that were captured and temporarily contained at spring stopover. We found that fuel reserves at capture were positively correlated with Zugunruhe, and negatively correlated with fuel accumulation. This indicates that fat birds were motivated to depart, whereas lean birds were set on staying and accumulating fuel. Moreover, the change in fuel reserves was positively correlated with the concurrent change in Zugunruhe, providing the first empirical evidence for a direct link between fuel accumulation and Zugunruhe during stopover. Our study indicates that, together with innate rhythms and weather, the size and accumulation of fuel reserves shape stopover duration, and hence overall migration time.

Long-distance wh-movement and long-distance wh-movement avoidance in L2 English: Evidence from French and Bulgarian speakers

2014 ◽  
Vol 31 (2) ◽  
pp. 179-210 ◽  
Author(s):  
Nikolay Slavkov
Keyword(s):  
Second Language ◽  
Second Language Acquisition ◽  
Language Acquisition ◽  
First Language ◽  
Processing Load ◽  
Long Distance ◽  
Canadian French ◽  
Equivalent Length ◽  
Show Evidence ◽  
L1 Acquisition

This article investigates spoken productions of complex questions with long-distance wh-movement in the L2 English of speakers whose first language is (Canadian) French or Bulgarian. Long-distance wh-movement is of interest as it can be argued that it poses difficulty in acquisition due to its syntactic complexity and related high processing load. Adopting the derivational complexity hypothesis, which has so far been applied to long-distance (LD) wh-movement in L1 acquisition and child second language acquisition, I argue that adult L2 learners also show evidence that questions with LD wh-movement are often replaced by alternative utterances with lower derivational complexity. I propose that such utterances, which are sometimes of equivalent length and with similar meaning to the targeted LD wh-structures, are avoidance strategies used by the learners as an intermediate acquisition resource. That is, such strategies are used as an escape-hatch from the derivational complexity of LD wh-movement. Overall, the results of this research indicate that the link between the number and complexity of derivational steps in a given structure is a fruitful area with strong potential in the second language acquisition field.

scholarly journals Great flights by great snipes: long and fast non-stop migration over benign habitats

2011 ◽  
Vol 7 (6) ◽  
pp. 833-835 ◽  
Author(s):  
Raymond H. G. Klaassen ◽  
Thomas Alerstam ◽  
Peter Carlsson ◽  
James W. Fox ◽  
Åke Lindström
Keyword(s):  
Migratory Birds ◽  
Strenuous Exercise ◽  
Migration Route ◽  
Long Distance ◽  
Migration Strategy ◽  
Ice Caps ◽  
Fuel Loads ◽  
Stopover Sites ◽  
Ecological Barriers ◽  
Suitable Habitats

Migratory land birds perform extreme endurance flights when crossing ecological barriers, such as deserts, oceans and ice-caps. When travelling over benign areas, birds are expected to migrate by shorter flight steps, since carrying the heavy fuel loads needed for long non-stop flights comes at considerable cost. Here, we show that great snipes Gallinago media made long and fast non-stop flights (4300–6800 km in 48–96 h), not only over deserts and seas but also over wide areas of suitable habitats, which represents a previously unknown migration strategy among land birds. Furthermore, the great snipes achieved very high ground speeds (15–27 m s −1 ), which was not an effect of strong tailwind support, and we know of no other animal that travels this rapidly over such a long distance. Our results demonstrate that some migratory birds are prepared to accept extreme costs of strenuous exercise and large fuel loads, even when stopover sites are available along the route and there is little tailwind assistance. A strategy of storing a lot of energy before departure, even if migration is over benign habitats, may be advantageous owing to differential conditions of fuel deposition, predation or infection risk along the migration route.

scholarly journals Characterization of components of Z-bands in the fibrillar flight muscle of Drosophila melanogaster.

1989 ◽  
Vol 109 (5) ◽  
pp. 2157-2167 ◽  
Author(s):  
J D Saide ◽  
S Chin-Bow ◽  
J Hogan-Sheldon ◽  
L Busquets-Turner ◽  
J O Vigoreaux ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Monoclonal Antibodies ◽  
Flight Muscle ◽  
Cross Reactivity ◽  
Antigenic Determinants ◽  
Immunogold Staining ◽  
Thick Filaments ◽  
The Matrix ◽  
Flight Muscles

Twelve monoclonal antibodies have been raised against proteins in preparations of Z-disks isolated from Drosophila melanogaster flight muscle. The monoclonal antibodies that recognized Z-band components were identified by immunofluorescence microscopy of flight muscle myofibrils. These antibodies have identified three Z-disk antigens on immunoblots of myofibrillar proteins. Monoclonal antibodies alpha:1-4 recognize a 90-100-kD protein which we identify as alpha-actinin on the basis of cross-reactivity with antibodies raised against honeybee and vertebrate alpha-actinins. Monoclonal antibodies P:1-4 bind to the high molecular mass protein, projectin, a component of connecting filaments that link the ends of thick filaments to the Z-band in insect asynchronous flight muscles. The anti-projectin antibodies also stain synchronous muscle, but, surprisingly, the epitopes here are within the A-bands, not between the A- and Z-bands, as in flight muscle. Monoclonal antibodies Z(210):1-4 recognize a 210-kD protein that has not been previously shown to be a Z-band structural component. A fourth antigen, resolved as a doublet (approximately 400/600 kD) on immunoblots of Drosophila fibrillar proteins, is detected by a cross reacting antibody, Z(400):2, raised against a protein in isolated honeybee Z-disks. On Lowicryl sections of asynchronous flight muscle, indirect immunogold staining has localized alpha-actinin and the 210-kD protein throughout the matrix of the Z-band, projectin between the Z- and A-bands, and the 400/600-kD components at the I-band/Z-band junction. Drosophila alpha-actinin, projectin, and the 400/600-kD components share some antigenic determinants with corresponding honeybee proteins, but no honeybee protein interacts with any of the Z(210) antibodies.

scholarly journals Birds facing climate change: a qualitative model for the adaptive potential of migratory behaviour

2015 ◽  
Vol 85 (1) ◽  
pp. 3 ◽  
Author(s):  
Michelangelo Morganti
Keyword(s):  
Climate Change ◽  
Phenotypic Plasticity ◽  
Migratory Birds ◽  
Future Research ◽  
Qualitative Model ◽  
Migratory Behaviour ◽  
Adaptive Potential ◽  
Long Distance ◽  
Genetic Determination ◽  
Recent Climate

Recent climate change is altering the migratory behaviour of many bird species. An advancement in the timing of spring events and a shift in the geographical distribution have been detected for birds around the world. In particular, intra-Palearctic migratory birds have advanced arrivals in spring and shortened migratory distances by shifting northward their wintering grounds. These changes in migratory patterns are considered adaptive responses facilitating the adjustment of the life cycle to the phenological changes found in their breeding areas. However, in some cases, populations exposed to the same selective pressures do not show any appreciable adaptive change in their behaviour. Basing on the comparison of realized and non-realized adaptive changes, I propose here the formulation of a qualitative model that predicts the potential of migratory birds populations to change adaptively their migratory behaviour. The model assumes that the adaptive potential of migratory behaviour is fuelled by both genetic diversity and phenotypic plasticity. Populations of long-distance migrants are exposed to strong environmental canalization that largely eroded their phenotypic plasticity and reduced genetic variability, so that they show a very low amount of adaptive potential regarding migratory behaviour. On the contrary, partial-migrant populations have a highly varied genetic profile and are more plastic at the phenotypic level, and consequently show the highest amount of adaptive potential. Species with mainly social and mainly genetic determination of the migratory behaviour are separately treated in the model. Specific empirical models to foresee the adaptive strategies of wild bird populations that face to climate change can be derived from the general theoretical model. As example, a specific model about the shortening of migratory distances in Western European migratory bird is presented. Finally, a number of future research lines on the topic of adaptive potential of migratory behaviour are discussed, including some examples of concrete study cases. In conclusion, partial-migration emerge as the less known system and future research efforts on this topic are expected to be especially fruitful.

scholarly journals The Hippo pathway controls myofibril assembly and muscle fiber growth by regulating sarcomeric gene expression

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Aynur Kaya-Çopur ◽  
Fabio Marchiano ◽  
Marco Y Hein ◽  
Daniel Alpern ◽  
Julie Russeil ◽  
...  
Keyword(s):  
Gene Expression ◽  
Muscle Fiber ◽  
Flight Muscle ◽  
Hippo Pathway ◽  
Muscle Fibers ◽  
Muscle Growth ◽  
Fiber Growth ◽  
Flight Muscles ◽  
Sarcomeric Gene ◽  
The Hippo Pathway

Skeletal muscles are composed of gigantic cells called muscle fibers, packed with force-producing myofibrils. During development the size of individual muscle fibers must dramatically enlarge to match with skeletal growth. How muscle growth is coordinated with growth of the contractile apparatus is not understood. Here, we use the large Drosophila flight muscles to mechanistically decipher how muscle fiber growth is controlled. We find that regulated activity of core members of the Hippo pathway is required to support flight muscle growth. Interestingly, we identify Dlg5 and Slmap as regulators of the STRIPAK phosphatase, which negatively regulates Hippo to enable post-mitotic muscle growth. Mechanistically, we show that the Hippo pathway controls timing and levels of sarcomeric gene expression during development and thus regulates the key components that physically mediate muscle growth. Since Dlg5, STRIPAK and the Hippo pathway are conserved a similar mechanism may contribute to muscle or cardiomyocyte growth in humans.

Flight muscle and flight activity of melon fly, Bactrocera cucurbitae (Diptera: Tephritidae)

2021 ◽  
Vol 30 (2) ◽  
pp. 179-185
Author(s):  
Farhana Ferdousi ◽  
Shanjida Sultana ◽  
Tangin Akter ◽  
Pinakshi Roy ◽  
Shefali Begum
Keyword(s):  
Longitudinal Muscle ◽  
Flight Muscle ◽  
Flight Activity ◽  
The Other ◽  
Bactrocera Cucurbitae ◽  
Male And Female ◽  
Melon Fly ◽  
Length Width ◽  
Flight Muscles ◽  
The Mean

The flight activity and flight muscle of the melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) were observed. The Tethered technique was used to observe the flight activity in this study. The flight activity, and wing and flight muscles were compared between male and female melon flies. The results indicate that the female was relatively better and strong flier than the male. The mean duration of the flight activity of the females was 13.90 min/hour and of the males was 7.12 min./hour. The mean length, width, volume of wings of the males were 6.07 mm, 2.67 mm and 10.99 mm³, respectively. On the other hand, the mean length, width and volume of the wings of females were 7.07 mm, 2.87 mm and 15.60 mm³, respectively. In case of wing muscles, the mean volume of dorsal longitudinal muscle (DLM) in male and female was found 5.20 mm³ and 5.67 mm³, respectively. The mean length of flight wing muscle of male and female was 2.22 and 2.23 mm, respectively and the mean breadth of male and female was 1.65 and 1.77 mm, respectively. Dhaka Univ. J. Biol. Sci. 30(2): 179-185, 2021 (July)

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