scholarly journals Flexibility and Control of Circadian Activity, Migratory Restlessness and Fueling in Two Songbird Migrants

2021 ◽  
Vol 9 ◽  
Author(s):  
Susanne Åkesson ◽  
Mihaela Ilieva ◽  
Giuseppe Bianco
Keyword(s):  
Fuel Load ◽  
Time Shift ◽  
Limited Attention ◽  
Control Group ◽  
Migratory Restlessness ◽  
Migratory Activity ◽  
Natural Photoperiod ◽  
Timing Of Migration ◽  
Species Specific ◽  
Flexible Component

Juvenile songbirds rely on an endogenous program, encoding direction, distance, fueling, and timing of migration. Migratory distance is species-specific, expressed as a period of migratory restlessness, for which the length is correlated with distance, while fueling is modified to meet anticipated flight distances controlled by geomagnetic cues and amount of day-light available for foraging. How daylength affect onset and level of migratory activity and fueling decisions in wild birds have so far received limited attention. Here we study how photoperiod controls onset, level and extent of autumn migratory activity and fueling in juvenile diurnally migrating dunnocks, and nocturnally migrating European robins by experimentally increasing daylength. For both species, we kept a control group indoors at the location of capture in southern Sweden exposed to the natural photoperiod, and an experimental group with increased and advanced photoperiod by 2 h in the morning. Dunnocks initiated migratory activity at sunrise (or artificial sunrise) in both groups, demonstrating a highly responsive and flexible component for the onset of migration triggered by light. Experimental robins anticipated the end of nocturnal migratory activity predicting the earlier sunrise immediately after the time-shift and expressed this behavior already under darkness, supporting a fast-resetting mechanism to the new diel period. Timing of end of morning activity was not affected by the earlier sunrise in both species, suggesting a fixed endogenous control that persisted throughout the 13-day study period. Experimental dunnocks expressed higher overall activity and lower fuel loads than controls, while robins did not change their overall activity and fuel load in response to the shifted and increased photoperiod. These results reveal important adaptations for circadian timekeeping including both a flexible onset open to fast modifications and a more rigid end, with differential effects by the treatment on migratory activity and fueling in the two species.

Do New Chiefs Mean Fresh Perspectives? The Institutionalization of the Police Executive Environment

2021 ◽  
pp. 009385482110067
Author(s):  
Matthew C. Matusiak
Keyword(s):  
Law Enforcement ◽  
Regression Models ◽  
Ordinary Least Squares ◽  
Limited Attention ◽  
Control Group ◽  
Multivariate Methods ◽  
Environmental Perceptions ◽  
Police Organizations ◽  
Law Enforcement Agency ◽  
Time Periods

Research suggests policing is a highly institutionalized field. Limited attention has been paid, however, to the institutionalization of leaders’ views. Assessing turnover in 71 Texas police organizations between October, 2011, and July, 2015, this research evaluates whether there is consistency (i.e., institutional homogenization) after turnover in chiefs’ perceptions of their environments and agency priorities. The research is unique in that it assesses two chiefs’ perceptions that have both led the same law enforcement agency in successive time periods. Assessments of environment and priorities from former chiefs and those replacing them are evaluated utilizing descriptive, bivariate, and multivariate methods. These assessments are also compared with a control group of chiefs from agencies not experiencing turnover. Bivariate results suggest little variation across current and former chiefs, whereas ordinary least squares (OLS) regression models suggest differing relationships across chiefs groups between environmental perceptions and agency priorities. Discussion of the findings is framed by institutional theory.

scholarly journals Embryo-induced transcriptome changes in bovine endometrium reveal species-specific and common molecular markers of uterine receptivity

Reproduction ◽  
2006 ◽  
Vol 132 (2) ◽  
pp. 319-331 ◽  
Author(s):  
Stefan Bauersachs ◽  
Susanne E Ulbrich ◽  
Karin Gross ◽  
Susanne E M Schmidt ◽  
Heinrich H D Meyer ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Molecular Mechanisms ◽  
Cdna Array ◽  
Early Embryo ◽  
Cdna Libraries ◽  
Control Group ◽  
Regulation Of Transcription ◽  
Uterine Receptivity ◽  
Subtracted Cdna Libraries ◽  
Species Specific

The endometrium plays a central role among the reproductive tissues in the context of early embryo–maternal communication and pregnancy. This study investigated transcriptome profiles of endometrium samples from day 18 pregnant vs non-pregnant heifers to get insight into the molecular mechanisms involved in conditioning the endometrium for embryo attachment and implantation. Using a combination of subtracted cDNA libraries and cDNA array hybridisation, 109 mRNAs with at least twofold higher abundance in endometrium of pregnant animals and 70 mRNAs with higher levels in the control group were identified. Among the mRNAs with higher abundance in pregnant animals, at least 41 are already described as induced by interferons. In addition, transcript levels of many new candidate genes involved in the regulation of transcription, cell adhesion, modulation of the maternal immune system and endometrial remodelling were found to be increased. The different expression level was confirmed with real-time PCR for nine genes. Localisation of mRNA expression in the endometrium was shown byin situhybridisation forAGRN,LGALS3BP,LGALS9,USP18,PARP12andBST2. A comparison with similar studies in humans, mice, and revealed species-specific and common molecular markers of uterine receptivity.

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.

The relationship between plasma testosterone concentrations and the seasonal variation in voluntary feed intake in fallow bucks (Dama dama)

1998 ◽  
Vol 130 (3) ◽  
pp. 357-366 ◽  
Author(s):  
R. E. NEWMAN ◽  
S. J. McCONNELL ◽  
R. H. WESTON ◽  
M. REEVES ◽  
C. BERNASCONI ◽  
...  
Keyword(s):  
Feed Intake ◽  
Plasma Concentrations ◽  
Plasma Free Fatty Acid ◽  
Reproductive Behaviour ◽  
Fallow Deer ◽  
Plasma Testosterone ◽  
Control Group ◽  
Voluntary Feed Intake ◽  
Natural Photoperiod ◽  
The Relationship

In two experiments conducted at Badgery's Creek, NSW (Latitude 34°S) the roles of testosterone and the thyroid hormones triiodothyronine (T3) and thyroxine (T4) as possible initiators of the change in voluntary feed intake (VFI) associated with the seasonal reproductive behaviour (rut) in male fallow deer were investigated.In Expt 1, the association between changes in these hormones with the onset of the rut was assessed in deer in which the timing of this event was manipulated by changing the photoperiod, or by melatonin administration. Groups were maintained under either natural photoperiod (n=6; control), a constant long daylength (16 h light[ratio ]8 h dark; n=9; LD group) or a constant long daylength and implanted with melatonin capsules (n=5; LD+M group) for 7 months from December until the following July. Blood samples were obtained weekly and VFI recorded.Feed intake decreased by 94% from the last week of March for 3 weeks in the control group. Changes of a similar magnitude were measured in the LD and LD+M groups but these changes were advanced by 1 and 9 weeks respectively in these groups. In all groups, circulating testosterone concentrations increased markedly at a time corresponding with the decrease in VFI. The concentrations returned to basal levels with the resumption in VFI. A distinct decrease in plasma concentrations of T3 and T4 in all three groups was associated with the decrease in VFI, however, the relationship with T3 was less apparent.In Expt 2, the role of testosterone in the regulation of the decline in VFI was investigated. Fallow bucks were treated with testosterone enanthate every 4 or 5 days for 28 days up to 6 weeks prior to the expected onset of the rut. Plasma testosterone concentrations, which were increased 13-fold, resulted in a decline in VFI which was comparable to that observed in the subsequent rut. Plasma free fatty acid concentrations were correlated negatively with the decline in VFI.Thus, the seasonal increase in circulating testosterone concentrations plays an important role in initiating the fall in VFI associated with the rut. As the rut was still apparent in animals maintained under an extended photoperiod, it is possible that factors other than decreasing daylength act as the cue for the timing of the rut.

scholarly journals Estimating Fuel Loads and Structural Characteristics of Shrub Communities by Using Terrestrial Laser Scanning

2020 ◽  
Vol 12 (22) ◽  
pp. 3704
Author(s):  
Cecilia Alonso-Rego ◽  
Stéfano Arellano-Pérez ◽  
Carlos Cabo ◽  
Celestino Ordoñez ◽  
Juan Gabriel Álvarez-González ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Goodness Of Fit ◽  
Fire Hazard ◽  
Structural Characteristics ◽  
Fire Behavior ◽  
Terrestrial Laser Scanning ◽  
Fuel Load ◽  
Fuel Loads ◽  
Litter Depth ◽  
Species Specific

Forest fuel loads and structural characteristics strongly affect fire behavior, regulating the rate of spread, fireline intensity, and flame length. Accurate fuel characterization, including disaggregation of the fuel load by size classes, is therefore essential to obtain reliable predictions from fire behavior simulators and to support decision-making in fuel management and fire hazard prediction. A total of 55 sample plots of four of the main non-tree covered shrub communities in NW Spain were non-destructively sampled to estimate litter depth and shrub cover and height for species. Fuel loads were estimated from species-specific equations. Moreover, a single terrestrial laser scanning (TLS) scan was collected in each sample plot and features related to the vertical and horizontal distribution of the cloud points were calculated. Two alternative approaches for estimating size-disaggregated fuel loads and live/dead fractions from TLS data were compared: (i) a two-steps indirect estimation approach (IE) based on fitting three equations to estimate shrub height and cover and litter depth from TLS data and then use those estimates as inputs of the existing species-specific fuel load equations by size fractions based on these three variables; and (ii) a direct estimation approach (DE), consisting of fitting seven equations, one for each fuel fraction, to relate the fuel load estimates to TLS data. Overall, the direct approach produced more balanced goodness-of-fit statistics for the seven fractions considered jointly, suggesting that it performed better than the indirect approach, with equations explaining more than 80% of the observed variability for all species and fractions, except the litter loads.

scholarly journals Site- and species-specific fuel load of European–Afrotropical passerines on arrival at three oases of southeast Morocco during spring migration

Bird Study ◽  
2013 ◽  
Vol 60 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Juan Arizaga ◽  
Ivan Maggini ◽  
Fadwa Hama ◽  
Ariñe Crespo ◽  
Gabriel Gargallo
Keyword(s):  
Spring Migration ◽  
Fuel Load ◽  
Species Specific

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 Effect of immunological castration of male pigs on morphological and functional con-dition of the testicles

2021 ◽  
Vol 12 (1) ◽  
pp. 20-26
Author(s):  
V. V. Samoilіuk ◽  
M. S. Koziy ◽  
D. D. Bilyi ◽  
S. M. Maslikov ◽  
Т. L. Spitsina ◽  
...  
Keyword(s):  
Testosterone Level ◽  
Leydig Cells ◽  
Functional Condition ◽  
Time Shift ◽  
Seminiferous Tubules ◽  
Control Group ◽  
Interstitial Tissue ◽  
Livestock Products ◽  
Degree Of Differentiation ◽  
Immunological Castration

Changes in the priorities of the treatment of animals in the conditions of intense technology of production of livestock products are based on the necessity of wellbeing of animals. Therefore, there is a need of search for and broad introduction of generally accepted alternatives to surgery, which would use modern means of castration, particularly immunocastration. The study presents morpho-functional substantiation of practicability of using immunological castration in the conditions of industrial production of pork. At the same time, we studied immunological castration using Improvak on the morphological and physiological condition of the testicles of male pigs. The testosterone level was determined using radioimmunologic method after 2, 4, 6, 8 weeks of immunological and surgical castrations, and also in intact boars of the control group. During the slaughter, we selected biopates of the testicles in immunological castrates and pigs of the control group for histological examination. The testosterone level 2 weeks after castration was the lowest in the animals castrated using Improvak. This indicator gradually increased, and after 8 weeks was higher than in the surgically castrated pigs. In the latter, the level of testosterone gradually decreased for 8 weeks, and did not significantly change in non-castrated pigs. The last stages of spermatogenesis in immunocastrates were inhibited after the second vaccination. As a result of immunological castration, the interstitial tissue of the testicle underwent changes. Between the tubules, a spreading of the loose connective tissue was observed. Leydig cells lost hyper chromaticity of the cytoplasm and typical polygonal profile, and their functional potential decreased. This fact was confirmed by the changes in the Hertwig’s ratio. In particular, we observed decrease in the value of the nuclear-cytoplasmic ratio. There were also a time shift of mitotic cycle, low degree of differentiation of spermatogonia and rupture of the course of the subsequent stages of spermatogenesis. However, there occurred multiplication of primary spermatogonia, single cellular divisions, and in the ductus deferentes, there could be found single spermatids. Some of them formed specific cellular groups of rounded and elliptic shapes in the seminiferous tubules. These structures were absent in the testicles of the control animals. Microstructural changes in the swine after injecting Improvak were characterized by deficiency of Leydig cells, indicating absence of the normal hormonal background, as confirmed by the results of the study of testosterone level. The epithelium-spermatogenic layer was underdeveloped, and the lumens of the tubules were in some places filled with generations of spermatocytes. In some places, meiosis was observed, which also indicates insignificant functioning of the testicles. Vaccination with Improvak caused atrophy of the testicles in swine and decrease in their functional condition, allowing it to be recommended it for broader application as an alternative to surgical castration.

In-cage sandbox as a ground substitute for farmed blue foxes (Alopex lagopus): Effects on digging activity and welfare

2003 ◽  
Vol 83 (4) ◽  
pp. 703-712 ◽  
Author(s):  
H. T. Korhonen ◽  
L. Jauhiainen ◽  
T. Rekilä
Keyword(s):  
Test Group ◽  
Experimental Period ◽  
Quality Parameters ◽  
Control Group ◽  
Alopex Lagopus ◽  
Field Activity ◽  
Body Weights ◽  
Novel Objects ◽  
Fur Quality ◽  
Species Specific

A study on the behavioural and welfare effects of in-cage sandboxes was carried out on juvenile farm-bred blue foxes (Alopex lagopus) with special reference to digging behaviours and time spent on sand substrate. Twelve juvenile male blue foxes were used in each of two experimental groups: (1) a test group and (2) a control group. Animals were raised singly in cages measuring 120 cm long × 105 cm wide × 70 cm high, from weaning in July to pelting in December. All experimental animals were housed conventionally but cages of the test group contained in-cage sandboxes (80 cm long × 40 cm wide × 14 cm high). Various physiological, behavioural, health and production related variables were measured during the study. Final body weights of test animals were significantly (P = 0.05) lower than controls. Occurrence of endoparasites (Toxascaris leonina, Isospora sp.) did not substantially differ between groups. Open field activity was greater (P = 0.02) and latency to touch novel objects shorter (P = 0.02) in the test group compared with the control. Cortisol-creatinine ratio, incidence of stereotypes, size of adrenals or other organs, blood screen and fur quality parameters were not significantly different. Sandbox hygiene deteriorated rapidly during the experimental period. Fur coats of test animals were dirtier than those of controls at pelting. Claw length of test animals was significantly shorter (front foot; P < 0.005, back foot, P < 0.001) than in controls only in October. Altogether nine different sandbox behaviours were observed in the test foxes. Digging was the fifth most common behavior, comprising 5.8% of total sandbox use. Amount of time spent in the sandbox peaked in July, averaging 117 min/24 h, and declined towards winter. The most common sandbox behaviours observed were walking (24.3% of total time), sitting (22.0%) and resting (17.5%). Results indicated low motivation to use in-cage sandboxes as a digging substrate. On the other hand, the presence of in-cage sandboxes may provide opportunities for foxes to engage in other species-specific activities and/or seek sensory comfort through contact with the sand. The effects of in-cage sandboxes on animal welfare need further study. Key words: Alopex lagopus, sand floor, digging, motivation, welfare, fur farming

scholarly journals Effects of Electrical Pulse Stimulation on Behaviour and Survival of Marine Benthic Invertebrates

2021 ◽  
Vol 7 ◽  
Author(s):  
Pim G. Boute ◽  
Maarten Soetaert ◽  
José A. Reid Navarro ◽  
Martin J. Lankheet
Keyword(s):  
Electrical Stimulation ◽  
Benthic Invertebrates ◽  
Marine Ecosystem ◽  
Electrical Pulse ◽  
Control Group ◽  
Electrical Pulse Stimulation ◽  
Species Survival ◽  
Electrical Pulses ◽  
Visible Effect ◽  
Species Specific

Electrical pulse trawling is an alternative to conventional beam trawling for common sole (Solea solea), with the potential for higher revenues and less impact on the marine ecosystem. Concerns exist, however, that benthic invertebrates might be seriously affected by pulse fishing. Even if direct injuries and mortality were limited, changes in behaviour might compromise their survival, with potentially large impacts on food webs. Here, we investigate effects of electrical pulses on locomotion behaviour and 14-days survival of six invertebrate species from four phyla that may encounter pulse fishing gears. Electrical stimulation consisted of a Pulsed Bipolar Current at 200 V m–1, 30 Hz, 0.33 ms pulse width, and 3 s duration. We quantified species-specific behaviours before, during, and after electrical stimulation and compared these to a non-exposed control group. Responses during stimulation varied from no visible effect (echinoderms) to squirming (sea mouse) and retractions (whelk and crustaceans). Within 30 s after stimulation, all animals resumed normal behavioural patterns, without signs of lasting immobilisation. Starfish, serpent star, whelk and sea mouse showed no change in movement patterns after stimulation, whereas flying crab and hermit crab showed significant changes in activity that were indicative of increased shelter behaviour. For none of the species, survival at 14-days after stimulation was negatively affected. These findings suggest that changes in locomotion behaviour due to electrical stimulation as used in pulse trawling are unlikely to substantially compromise survival of the investigated species.

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