Search results for "Animal Migration"
showing 10 items of 66 documents
Polymorphism in Developmental Mode and Its Effect on Population Genetic Structure of a Spionid Polychaete, Pygospio elegans
2012
Population genetic structure of sedentary marine species is expected to be shaped mainly by the dispersal ability of their larvae. Long-lived planktonic larvae can connect populations through migration and gene flow, whereas species with nondispersive benthic or direct-developing larvae are expected to have genetically differentiated populations. Poecilogonous species producing different larval types are ideal when studying the effect of developmental mode on population genetic structure and connectivity. In the spionid polychaete Pygospio elegans, different larval types have been observed between, and sometimes also within, populations. We used microsatellite markers to study population st…
Using genetic markers to unravel the origin of birds converging towards pre-migratory sites
2018
AbstractIdentifying patterns of individual movements in spatial and temporal scales can provide valuable insight into the structure of populations and the dynamics of communities and ecosystems. Especially for migrating birds, that can face a variety of unfavorable conditions along their journey, resolving movements of individuals across their annual cycle is necessary in order to design better targeted conservation strategies. Here, we studied the movements of a small migratory falcon, the Lesser Kestrel (Falco naumanni), by genetically assigning feathers from individuals of unknown origin that concentrate in large roosts during the pre-migratory period. Our findings suggest that birds fro…
Short-term occupations at high elevation during the Middle Paleolithic at Kalavan 2 (Republic of Armenia).
2021
The Armenian highlands encompasses rugged and environmentally diverse landscapes and is characterized by a mosaic of distinct ecological niches and large temperature gradients. Strong seasonal fluctuations in resource availability along topographic gradients likely prompted Pleistocene hominin groups to adapt by adjusting their mobility strategies. However, the role that elevated landscapes played in hunter-gatherer settlement systems during the Late Pleistocene (Middle Palaeolithic [MP]) remains poorly understood. At 1640 m above sea level, the MP site of Kalavan 2 (Armenia) is ideally positioned for testing hypotheses involving elevation-dependent seasonal mobility and subsistence strateg…
Population structure in Atlantic cod in the eastern North Sea-Skagerrak-Kattegat: early life stage dispersal and adult migration.
2015
Background In marine fish species, where pelagic egg and larvae drift with ocean currents, population structure has been suggested to be maintained by larval retention due to hydrographic structuring and by homing of adult fish to natal areas. Whilst natal homing of adults has been demonstrated for anadromous and coral reef fishes, there are few documented examples of philopatric migration in temperate marine fish species. Results Here, we demonstrate temporally stable genetic differentiation among spawning populations of Atlantic cod (Gadus morhua L.), and present genetic and behavioural evidence for larval drift and philopatric migration in the eastern North Sea-Skagerrak-Kattegat area. W…
Inferring genetic connectivity in real populations, exemplified by coastal and oceanic atlantic cod
2018
Significance Estimates of migration are important for understanding the dynamics of natural populations. A statistic known as FST is often used to measure levels of genetic differentiation among natural populations. Equations that translate FST into estimates of migration are based on “ideal” populations, which are subject to many simplifying assumptions compared with real populations. Therefore, theoretical estimates of migration might not be realistic. We modeled populations of Atlantic cod in the North Sea and the adjacent Skagerrak region to compare how migration is related to the complexities of real populations, and how actual migration compares with predictions based on theory. Resul…
Ecological specialization to fluctuating resources prevents long-distance migratory raptors from becoming sedentary on islands
2013
[Background]: The adaptive transition between behavioral strategies, such as the shift from migratoriness to sedentariness, remains an outstanding question in evolutionary ecology. Density-dependent variation in the age of first breeding has been proposed as a feasible mechanism through which long-lived migratory birds with deferred sexual maturity should become sedentary to persist on islands. Although this pattern seems to hold for most raptors and herons, a few exceptions have been identified. One of these exceptions is the Eleonora's falcon, a long-distance migratory bird, which shows one of the most peculiar adaptations in the timing of reproduction and food requirements among raptors.…
Seasonal Distribution and Movement of the Invasive Pest Delottococcus aberiae (Hemiptera: Pseudococcidae) Within Citrus Tree: Implications for Its In…
2018
[EN] Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is the most recent species of mealybug introduced to Spain that is affecting citrus. The feeding behavior of D. aberiae causes severe direct damage to citrus fruits, distorting their shape and/or causing reduction in size. There is no information available regarding its distribution within the citrus trees. The main objective of this study was to describe the seasonal distribution of D. aberiae within citrus trees and its migration patterns on the plants. Ten citrus orchards from eastern Spain were periodically sampled during 3 yr. In each orchard, the mealybug was sampled in different infested strata (canopy, trunk, and soil…
Stock-specific variation of trophic position, diet and environmental stress markers in Atlantic salmon Salmo salar during feeding migrations in the B…
2012
This study investigated stock-specific variation in selected ecophysiological variables during the feeding migrations of Atlantic salmon Salmo salar in the Baltic Sea. Oxidative stress biomarkers and EROD (ethoxyresorufin-O-deethylase, Cyp1A enzyme) activity were used as indicators of possible environmental stress and stable isotopes as determinants of diet and trophic position. Latvian S. salar stocks Daugava and Gauja had distinct stable-isotope signatures compared to the other stocks, indicating differences in migration patterns, residency or arrival times, or dietary specialization among stocks. Salmo salar originating from Daugava and Gauja also had lower catalase enzyme activity than …
Do otolith annular structures correspond to the first freshwater entry for yellow European eelsAnguilla anguillain the Baltic countries?
2010
To examine the relationship between freshwater entry and otolith annular structures, a total of 113 naturally recruited European eels Anguilla anguilla from Lithuania and Latvia that entered fresh water at least once were collected. In some individuals (8.3-11.3%), the first freshwater entry coincided with a dark check that was distinctly different from neighbouring annuli. In most individuals (81.7-84.9%), the first freshwater entry occurred on rings and increments indistinguishable from other annuli. For the remaining individuals (3.8-10%), the first freshwater entry did not correspond to any otolith ring, band or annulus. According to recent evidence, the observed high correspondence bet…
Evidence for an Association between Post-Fledging Dispersal and Microsatellite Multilocus Heterozygosity in a Large Population of Greater Flamingos
2013
10 pages; International audience; DISPERSAL CAN BE DIVIDED INTO THREE STAGES: departure, transience and settlement. Despite the fact that theoretical studies have emphasized the importance of heterozygosity on dispersal strategies, empirical evidence of its effect on different stages of dispersal is lacking. Here, using multi-event capture-mark-recapture models, we show a negative association between microsatellite multilocus heterozygosity (MLH; 10 loci; n = 1023) and post-fledging dispersal propensity for greater flamingos, Phoenicopterus roseus, born in southern France. We propose that the negative effects of inbreeding depression affects competitive ability and therefore more homozygous…