Factors affecting individual variation in resting site fidelity in the patellid limpet, Cellana toreuma (Reeve)

1992 ◽  
Vol 7 (3) ◽  
pp. 305-331 ◽  
Author(s):  
Keiji Iwasaki
Keyword(s):  
Individual Variation ◽  
Site Fidelity ◽  
Factors Affecting

scholarly journals Factors affecting individual variation in nest-defense intensity in colonially breeding Black-tailed Gulls (Larus crassirostris)

2011 ◽  
Vol 89 (10) ◽  
pp. 938-944 ◽  
Author(s):  
Kentaro Kazama ◽  
Yasuaki Niizuma ◽  
Kentaro Q. Sakamoto ◽  
Yutaka Watanuki
Keyword(s):  
Individual Variation ◽  
Physiological State ◽  
Breeding Birds ◽  
Egg Laying ◽  
Nest Defense ◽  
Laying Date ◽  
Plasma Testosterone ◽  
Factors Affecting ◽  
Corvus Macrorhynchos ◽  
Males And Females

The physiological state of parent birds combined with the value of their clutch may affect the intensity of their nest defense. In colonially breeding birds, nest-defense intensity may also be affected by the behavior of neighbors. We investigated individual variation in the nest-defense intensity among colonial Black-tailed Gulls ( Larus crassirostris Vieillot, 1818) over 2 years. Only 30%–40% of males attacked a decoy of an egg predator (Large-billed Crow ( Corvus macrorhynchos Wagler, 1827)), and the other males and females rarely attacked. Males attacking the decoy had higher levels of plasma testosterone than males that did not attack. Each male’s, but not female’s, nest-defense intensity was consistent throughout the incubation period and also across years. The intensity was not related to egg-laying date, clutch size, or age of offspring. The intensity was likely to be higher when individuals had one or more neighbors, representing higher nest-defense intensity in the year where gulls had larger number of adjacent neighboring nests (5.23 nests), but this trend was not observed in the year where they had smaller number of the neighboring nests (3.73 nests). Thus, in addition to testosterone levels, behavior of neighbors also influences the nest-defense intensity.

Intralacustrine site fidelity and nonrandom mating in the littoral-spawning northern redbelly dace (Phoxinus eos)

2008 ◽  
Vol 65 (9) ◽  
pp. 2016-2025 ◽  
Author(s):  
Rachel Massicotte ◽  
Pierre Magnan ◽  
Bernard Angers
Keyword(s):  
Site Fidelity ◽  
Isolation By Distance ◽  
Reproductive Period ◽  
Nonrandom Mating ◽  
Factors Affecting ◽  
Hardy Weinberg Equilibrium ◽  
Allelic Differentiation ◽  
Evolutionary Perspectives ◽  
Uniform Population ◽  
Spawning Sites

Natal site fidelity of the northern redbelly dace ( Phoxinus eos ), a common minnow in North America, was confirmed by combining ecological and genetic approaches. A 2-year mark–recapture experiment conducted at four sites separated by 50–450 m strongly supported the propensity of the dace to practice site fidelity during the reproductive period. Individuals recaptured at their marking sites were characterized with five microsatellite loci. Hardy–Weinberg equilibrium and allelic differentiation tests revealed that the fish from different sites significantly differed from a single panmictic and genetically uniform population, thus confirming the homing behaviour of the dace. The detection of a pattern of isolation by distance revealed that migration mostly occurred between nearby sites and decreased as distance from birth site increased. When considering the high population density of dace, their high swimming capability, the distribution of the spawning sites along the littoral zone, and the small size of the lake studied (<5 ha), these results strongly suggest natal site fidelity in this species. The detection of this phenomenon for this species is extremely useful for empirical investigations of factors affecting patterns of isolation by distance and of evolutionary perspectives of natal site fidelity in fishes.

Serum pro-hepcidin concentrations and their responses to oral iron supplementation in healthy subjects manifest considerable inter-individual variation

2006 ◽  
Vol 44 (11) ◽  
Author(s):  
Susanna Luukkonen ◽  
Kari Punnonen
Keyword(s):  
Individual Variation ◽  
Healthy Subjects ◽  
Serum Iron ◽  
Iron Supplementation ◽  
Iron Homeostasis ◽  
Normal Serum ◽  
Serum Samples ◽  
Physiological Factors ◽  
Factors Affecting ◽  
Iron Iron

AbstractHepcidin participates in the regulation of iron homeostasis and its precursor pro-hepcidin can be measured in serum. We evaluated pro-hepcidin serum concentrations in healthy subjects and the possible effects of iron supplementation on the results. The results suggest extensive physiological variation in serum pro-hepcidin concentrations between healthy subjects with no symptoms or signs of anaemia, infections, inflammations, chronic disease or other interpretative factors. Before pro-hepcidin measurements can be used in clinical practise, further investigations are required to identify the physiological factors affecting normal serum pro-hepcidin variations in healthy subjects. The responses of serum pro-hepcidin to a 100-mg oral dose of iron also showed considerable inter-individual variation. In male subjects, no systematic changes in serum pro-hepcidin concentrations were found and the increase in serum iron was fairly modest. In nine out of the ten female subjects who had rather low amounts of storage iron, iron supplementation was followed by an increase in both serum iron and serum pro-hepcidin concentrations. There were considerable inter-individual differences in the timing and magnitude of the response. We also evaluated the conceivable influences of sample storage and freeze-thaw cycles on the results of serum pro-hepcidin ELISA. We did not observe any changes in the results after serum samples were frozen and thawed up to four times and/or stored at room temperature for up to 6h.Clin Chem Lab Med 2006;44:1361–2.

Long-term winter-site fidelity in Song Sparrows (Melospiza melodia)

The Auk ◽  
2019 ◽  
Vol 136 (2) ◽  
Author(s):  
Tosha R Kelly ◽  
Keith A Hobson ◽  
Garth W Casbourn ◽  
Elizabeth A MacDougall-Shackleton ◽  
Scott A MacDougall-Shackleton
Keyword(s):  
Population Dynamics ◽  
Site Fidelity ◽  
Migratory Birds ◽  
Melospiza Melodia ◽  
Factors Affecting ◽  
Song Sparrows ◽  
Breeding Grounds ◽  
Wintering Areas ◽  
Migratory Movements

Abstract In migratory animals, the degree to which individuals return to the same wintering sites across multiple years can affect fitness and population dynamics, and thus has important implications for conservation. Despite this, long-term evaluations of wintering-site fidelity are rare for migratory birds: many populations are intensively studied on their breeding grounds but tracking the migratory movements of small birds once they leave the breeding grounds is challenging. To evaluate patterns of overwintering location and fidelity, we collected winter-grown claw tissue from 301 Song Sparrows (Melospiza melodia; 449 samples) captured in spring at their breeding grounds over 6 consecutive yr and assessed stable hydrogen isotope (δ2Hc) values to determine within-individual repeatability and between-year variation in wintering latitudes. We also retrieved useable data from 8 geolocators over 2 consecutive winters. Geolocator-derived wintering positions correlated with origins based on δ2Hc values. Consistent with previous findings, male δ2Hc values reflected more northerly wintering areas than those of females, indicating shorter latitudinal migration distances for males, but the magnitude of the sex difference varied across years. The distribution of wintering latitudes was generally consistent among years, except for the 2015 舑2016 winter, which had unusually negative δ2Hc values. Values of δ2Hc were repeatable for males but not for females, suggesting that winter-site fidelity could differ between sexes. The data presented here emphasize the importance of tracking migratory populations across multiple years to uncover factors affecting population dynamics.

A note on factors affecting puberty in Clun Forest female lambs

1972 ◽  
Vol 15 (3) ◽  
pp. 311-314 ◽  
Author(s):  
Ó. R. Dýrmundsson ◽  
J. L. Lees
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Growth Rates ◽  
Individual Variation ◽  
Critical Factor ◽  
Factors Affecting ◽  
Marked Individual ◽  
Breeding Activity ◽  
Similar Growth

SUMMARYIn 1971 the attainment of puberty in 30 early-born and 30 late-born Chin Forest female lambs was studied. The early-born lambs showed their first oestrus at a mean age of 265·4 days and a mean body weight of 41·4 kg; the late-born lambs at 222·0 days and 36·8 kg.Marked individual variation existed in both age and body weight at puberty within the groups, largely because of differences in growth rate during rearing. Early-born singles showed their first oestrus on average 3·4 days earlier than twins while this difference between lateborn singles and twins was 17·9 days. Since early-born lambs attained puberty at a considerably higher mean age and heavier mean body weight than late-born lambs with similar growth rates it is suggested that the daylight environment experienced by the lamb may be a critical factor in regulating the onset of breeding activity.

Factors Affecting the Response of Trout to an Electric Field in Fresh and Salt Water

1967 ◽  
Vol 24 (1) ◽  
pp. 191-199 ◽  
Author(s):  
John E. C. Flux
Keyword(s):  
Electric Field ◽  
Individual Variation ◽  
Salmo Trutta ◽  
Salt Water ◽  
Current Field ◽  
Response Level ◽  
Factors Affecting ◽  
Wide Range ◽  
Field Temperature ◽  
Temperature Resistivity

The "minimum response" level of Salmo trutta to an alternating current field increased with angle to the field, temperature, resistivity, and fatigue, with a wide range of individual variation. The drop in potential across the length of a fish ("body-voltage") varies directly with length and is not a constant for the species in either fresh or salt water. Embryo trout show a fully developed response 2 weeks after hatching.

scholarly journals Factors affecting the measurement of absorption bands

1913 ◽  
Vol 86 (585) ◽  
pp. 128-140 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Individual Variation ◽  
Diffraction Grating ◽  
Wave Length ◽  
Absorption Bands ◽  
Factors Affecting ◽  
Definite Relationship ◽  
Percentage Saturation ◽  
Length Determination

In a previous paper a method was described by which the percentage saturation of hæmoglobin with carbon monoxide can be estimated. This was done by measuring with a special spectroscope the position of the absorption bands of a solution of blood, since it was found that a definite relationship exists between the percentage saturation with carbon monoxide and the wavelength of the bands. The principle used in the instrument was one first discovered by Zöllner in 1870 and called by him the reversion spectroscope. Two adjacent reversed spectra were obtained by passing beams through a slit suitably placed in relation to a reflecting prism and a replica diffraction grating, optical means being employed for shifting one of the spectra laterally, so that corresponding points in the spectra might be adjusted into line. Since first describing the method I have been able to investigate more thoroughly its accuracy both in my own hands and also in those of other observers. Two different classes of phenomena will receive attention, both of which tend to introduce complications in the use of the method when absolute values for the percentage saturation with carbon monoxide are required. These are:— ( a ) Variations in wave-length determinations made from time to time by same observer on different samples of blood (personal variation). ( b ) Variations in wave-length determination by different observers on same sample of blood (individual variation).

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