scholarly journals Dispersal distance is influenced by parental and grand-parental density

2014 ◽  
Vol 281 (1790) ◽  
pp. 20141061 ◽  
Author(s):  
E. V. Bitume ◽  
D. Bonte ◽  
O. Ronce ◽  
I. Olivieri ◽  
C. M. Nieberding
Keyword(s):  
Genetic Relatedness ◽  
Local Density ◽  
Dispersal Distance ◽  
Genetic Transmission ◽  
Parental Density ◽  
Transmission Of Information ◽  
Individual Offspring ◽  
Order Of Magnitude ◽  
Dispersal Distances ◽  
Two Spotted Spider Mite

Non-genetic transmission of information across generations, so-called parental effects, can have significant impacts on offspring morphology, physiology, behaviour and life-history traits. In previous experimental work using the two-spotted spider mite Tetranychus urticae Koch, we demonstrated that dispersal distances increase with local density and levels of genetic relatedness. We here show that manipulation of parental and grand-parental density has a significant effect on offspring dispersal distance, of the same order of magnitude as manipulation of offspring density. We demonstrate that offspring exposed to the same density disperse further if they were born to parents exposed to higher density compared with parents exposed to low density. Offspring dispersal distance also increases when grand-parents were exposed to higher density, except for offspring exposed to low densities, which disperse at shorter distances whatever the grand-parental density. We also show that offspring from mothers exposed to higher densities were overall larger, which suggests that parents in high densities invest more in individual offspring, enabling them to disperse further. We propose that our findings should be included in models investigating the spread rate of invasive species or when predicting the success of conservation measures of species attempting to track changing climates.

scholarly journals Interacting effects of forest fragmentation and howler monkey foraging on germination and disperal of fig seeds

Oryx ◽  
2002 ◽  
Vol 36 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Juan Carlos Serio-Silva ◽  
Victor Rico-Gray
Keyword(s):  
Dispersal Distance ◽  
Alouatta Palliata ◽  
Howler Monkey ◽  
Forest Fragment ◽  
Howler Monkeys ◽  
Conservation Policies ◽  
Dispersal Distances ◽  
Alouatta Palliata Mexicana ◽  
Fragmented Forests ◽  
Individual Trees

We studied changes in germination rates and dispersal distance of seeds of Ficus perforata and F. lundelli dispersed by howler monkeys (Alouatta palliata mexicana), in a small (40 ha) ‘disturbed’ and a larger (>600 ha) ‘preserved’ tropical rainforest in southern Veracruz, Mexico. The interaction between A. p. mexicana and Ficus (Urostigma) spp. is beneficial for the interacting species and has important implications for their conservation. Howler monkeys gain from the ingestion of an important food source, germination rates of Ficus seeds are improved by passage through the monkeys' digestive tract, and the seeds are more likely to be deposited in a site suitable for germination and development. Seed dispersal distances are relatively larger in the preserved site, with both the size of the forest area and the spatial pattern of Ficus affecting the dispersal process. In a large forest fragment with ‘regularly’ distributed Ficus individuals the howler monkeys move away from the seed source, increasing the probability that the seeds are desposited on a tree other than Ficus, which is important for the germination and future development of a hemiepiphytic species. In a small forest fragment with trees distributed in clumps howlers repeatedly use the same individual trees, and faeces containing seeds may be dropped on unsuitable trees more often. These are key issues when addressing conservation policies for fragmented forests.

scholarly journals Dispersal Kernel Determines Symmetry of Spread and Geographical Range for an Insect

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Jeffrey D. Holland
Keyword(s):  
Sugar Maple ◽  
Spatial Dynamics ◽  
Geographic Range ◽  
Dispersal Distance ◽  
Dispersal Kernel ◽  
Geographical Range ◽  
Spatial Distributions ◽  
Longhorned Beetle ◽  
Ecological Patterns ◽  
Dispersal Distances

The distance from a source patch that dispersing insects reach depends on the number of dispersers, or random draws from a probability density function called a dispersal kernel, and the shape of that kernel. This can cause asymmetrical dispersal between habitat patches that produce different numbers of dispersers. Spatial distributions based on these dynamics can explain several ecological patterns including megapopulations and geographic range boundaries. I hypothesized that a locally extirpated longhorned beetle, the sugar maple borer, has a new geographical range shaped primarily by probabilistic dispersal distances. I used data on occurrence from Ontario, Canada to construct a model of geographical range in Indiana, USA based on maximum dispersal distance scaled by habitat area. This model predicted the new range boundary within 500 m very accurately. This beetle may be an ideal organism for exploring spatial dynamics driven by dispersal.

scholarly journals Probability of successful larval dispersal declines fivefold over 1 km in a coral reef fish

2011 ◽  
Vol 279 (1735) ◽  
pp. 1883-1888 ◽  
Author(s):  
Peter M. Buston ◽  
Geoffrey P. Jones ◽  
Serge Planes ◽  
Simon R. Thorrold
Keyword(s):  
Larval Dispersal ◽  
Isolation By Distance ◽  
Dispersal Distance ◽  
Population Connectivity ◽  
Marine Ecology ◽  
Sea Anemones ◽  
Marine Population ◽  
Amphiprion Percula ◽  
Distance Distributions ◽  
Dispersal Distances

A central question of marine ecology is, how far do larvae disperse? Coupled biophysical models predict that the probability of successful dispersal declines as a function of distance between populations. Estimates of genetic isolation-by-distance and self-recruitment provide indirect support for this prediction. Here, we conduct the first direct test of this prediction, using data from the well-studied system of clown anemonefish ( Amphiprion percula ) at Kimbe Island, in Papua New Guinea. Amphiprion percula live in small breeding groups that inhabit sea anemones. These groups can be thought of as populations within a metapopulation. We use the x- and y -coordinates of each anemone to determine the expected distribution of dispersal distances (the distribution of distances between each and every population in the metapopulation). We use parentage analyses to trace recruits back to parents and determine the observed distribution of dispersal distances. Then, we employ a logistic model to (i) compare the observed and expected dispersal distance distributions and (ii) determine the relationship between the probability of successful dispersal and the distance between populations. The observed and expected dispersal distance distributions are significantly different ( p < 0.0001). Remarkably, the probability of successful dispersal between populations decreases fivefold over 1 km. This study provides a framework for quantitative investigations of larval dispersal that can be applied to other species. Further, the approach facilitates testing biological and physical hypotheses for the factors influencing larval dispersal in unison, which will advance our understanding of marine population connectivity.

scholarly journals The ACCELERATION programme: I. Cosmology with the redshift drift

2019 ◽  
Vol 492 (2) ◽  
pp. 2044-2057
Author(s):  
Ryan Cooke
Keyword(s):  
Local Density ◽  
Current Data ◽  
Cosmological Redshift ◽  
Star Forming ◽  
Star Forming Regions ◽  
Neutral Gas ◽  
Small Correction ◽  
Redshift Drift ◽  
Universal Expansion ◽  
Order Of Magnitude

ABSTRACT Detecting the change of a cosmological object’s redshift due to the time evolution of the Universal expansion rate is an ambitious experiment that will be attempted with future telescope facilities. In this paper, we describe the ACCELERATION programme, which aims to study the properties of the most underdense regions of the Universe. One of the highlight goals of this programme is to prepare for the redshift drift measurement. Using the EAGLE cosmological hydrodynamic simulations, we estimate the peculiar acceleration of gas in galaxies and the Lyα forest. We find that star-forming ‘cold neutral gas’ exhibits large peculiar acceleration due to the high local density of baryons near star-forming regions. We conclude that absorption by cold neutral gas is unlikely to yield a detection of the cosmological redshift drift. On the other hand, we find that the peculiar accelerations of Lyα forest absorbers are more than an order of magnitude below the expected cosmological signal. We also highlight that the numerous low H i column density systems display lower peculiar acceleration. Finally, we propose a new ‘Lyα cell’ technique that applies a small correction to the wavelength calibration to secure a relative measurement of the cosmic drift between two unrelated cosmological sources at different redshifts. For suitable combinations of absorption lines, the cosmological signal can be more than doubled, while the affect of the observer peculiar acceleration is mitigated. Using current data of four suitable Lyα cells, we infer a limit on the cosmological redshift drift to be $\dot{v}_{\rm obs}\lt 65~{\rm m~s}^{-1}~{\rm yr}^{-1}$ (2σ).

scholarly journals Sex-Related Natal Dispersal of Pied Flycatchers: How Far Away From Home?

The Condor ◽  
2006 ◽  
Vol 108 (3) ◽  
pp. 711-717
Author(s):  
Nikita Chernetsov ◽  
Leonid V. Sokolov ◽  
Vladislav Kosarev ◽  
Dmitry Leoke ◽  
Mikhail Markovets ◽  
...  
Keyword(s):  
Frequency Distribution ◽  
Null Model ◽  
Ficedula Hypoleuca ◽  
Dispersal Distance ◽  
Natal Dispersal ◽  
Nest Box ◽  
Nest Boxes ◽  
Baltic Coast ◽  
The Difference ◽  
Dispersal Distances

Abstract Over four years, nestling Pied Flycatchers (Ficedula hypoleuca) were banded and recaptured in nest boxes at a 44 km long and 1–1.5 km wide study area along the Courish Spit on the southeast Baltic coast. The return rate for males was nearly twice as high as for females. Males settled significantly closer to their natal sites than predicted by the null model, which assumed that any nest box in the study area was selected at random. For females, the frequency distribution of natal dispersal distances was not significantly different from that predicted by the null model. The difference in average dispersal distance between the sexes was highly significant. Although some individuals settled within tens of kilometers, most male Pied Flycatchers settled within several kilometers of their natal sites. We suggest that even if females settle on average farther from their natal sites than males do, both sexes imprint on a relatively small (several kilometers in diameter) area during postfledging exploration, to which they return each spring.

scholarly journals Social status, forest disturbance, and Barred Owls shape long-term trends in breeding dispersal distance of Northern Spotted Owls

The Condor ◽  
2019 ◽  
Vol 121 (4) ◽  
Author(s):  
Julianna M A Jenkins ◽  
Damon B Lesmeister ◽  
Eric D Forsman ◽  
Katie M Dugger ◽  
Steven H Ackers ◽  
...  
Keyword(s):  
Forest Disturbance ◽  
Dispersal Distance ◽  
Historical Study ◽  
Breeding Dispersal ◽  
Spotted Owls ◽  
Dispersal Distances ◽  
Dispersal Events ◽  
Northern Spotted Owls ◽  
Barred Owls ◽  
Over Time

Abstract Dispersal among breeding sites in territorial animals (i.e. breeding dispersal) is driven by numerous selection pressures, including competition and spatiotemporal variation in habitat quality. The scale and trend of dispersal movements over time may signal changing conditions within the population or on the landscape. We examined 2,158 breeding dispersal events from 694 male and 608 female individually marked Northern Spotted Owls (Strix occidentalis caurina) monitored over 28 yr on 7 study areas to assess the relative importance of individual (sex, experience), reproductive (annual productivity, mate availability), and environmental (forest alteration, presence of competitor) sources of variation in breeding dispersal distance. Median breeding dispersal distance was 3.17 km, with 99% of all breeding dispersal events &lt;37 km. Mean annual dispersal distances increased by 2.43 km in Oregon and 9.40 km in Washington between 1990 and 2017, which coincided with increases in annual detections of nonnative Barred Owl (S. varia). Frequency of breeding dispersal events, both among and within individuals, also increased over time. Female owls moved farther than males (median of 3.26 and 3.10 km, respectively), and birds with less experience (territory tenure) moved farther than those with more experience. Owls that were single in the year prior to dispersal moved 13–31% farther than those paired prior to dispersal. The greatest environmental change occurring over the course of our study was the expansion of Barred Owl populations. Breeding dispersal distance was positively related to Barred Owls in the study area and disturbance within the originating territory. While it appears that social factors continue to be important drivers of breeding dispersal distance in Spotted Owls, increased competition from Barred Owls and habitat alteration have a contributing effect. Increased breeding dispersal distances should be of concern for conservation efforts and considered in population monitoring because changing dispersal behavior may lead to higher rates of mortality and/or emigration from historical study areas.

scholarly journals Animal movement drives variation in seed dispersal distance in a plant–animal network

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182007 ◽  
Author(s):  
E. Rehm ◽  
E. Fricke ◽  
J. Bender ◽  
J. Savidge ◽  
H. Rogers
Keyword(s):  
Seed Dispersal ◽  
Animal Movement ◽  
Bird Species ◽  
Dispersal Distance ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Gut Passage ◽  
Dispersal Distances ◽  
Seed Dispersal Distance ◽  
Passage Times

Frugivores play differing roles in shaping dispersal patterns yet seed dispersal distance is rarely quantified across entire communities. We model seed dispersal distance using gut passage times and bird movement for the majority (39 interactions) of known bird–tree interactions on the island of Saipan to highlight differences in seed dispersal distances provided by the five avian frugivores. One bird species was found to be a seed predator rather than a disperser. The remaining four avian species dispersed seeds but differences in seed dispersal distance were largely driven by interspecific variation in bird movement rather than intraspecific variation in gut passage times. The median dispersal distance was at least 56 m for all species-specific combinations, indicating all species play a role in reducing high seed mortality under the parent tree. However, one species—the Micronesian Starling—performed 94% of dispersal events greater than 500 m, suggesting this species could be a key driver of long-distance dispersal services (e.g. linking populations, colonizing new areas). Assessing variation in dispersal patterns across this network highlights key sources of variation in seed dispersal distances and suggests which empirical approaches are sufficient for modelling how seed dispersal mutualisms affect populations and communities.

Genetic structure and dispersal of red foxes (Vulpes vulpes) in urban Melbourne

2001 ◽  
Vol 49 (6) ◽  
pp. 589 ◽  
Author(s):  
Nicholas A. Robinson ◽  
Clive A. Marks
Keyword(s):  
Vulpes Vulpes ◽  
Dispersal Distance ◽  
Regression Equations ◽  
Ecological Data ◽  
Red Foxes ◽  
Island Populations ◽  
Straight Line ◽  
Straight Line Distance ◽  
Dispersal Distances ◽  
Group Density

This study sought to investigate the potential for gene flow and dispersal between three sampled populations of urban Melbourne foxes (Vulpes vulpes). Five highly polymorphic canine microsatellites were used to investigate the population structure of foxes. The dispersal of 14 foxes, captured and radio-collared as cubs, were monitored periodically over two years. Dispersal estimates for males and females were also calculated from published regression equations that related social group density to dispersal distance. Genetic differentiation between urban populations was greater than between more widely spaced rural populations and was also greater than that found between San Remo and Phillip Island populations, which are separated by a water barrier. A deficiency of heterozygotes was detected in the total Melbourne population, but not at any of the field sites. Mean dispersal distances after 24 months (male = 3.5 km, female = 2.0 km) compared well with published accounts of dispersal in British cities. Dispersal distance estimates for female foxes from all sites were lower than straight-line distance for all but one site. Both the genetic and ecological data suggest a restricted ability for foxes to disperse between sites within urban Melbourne.

Dispersing Siberian flying squirrels (Pteromys volans) locate preferred habitats in fragmented landscapes

2012 ◽  
Vol 90 (7) ◽  
pp. 885-892 ◽  
Author(s):  
V. Selonen ◽  
I.K. Hanski
Keyword(s):  
Conservation Management ◽  
Dispersal Distance ◽  
High Quality ◽  
Fragmented Landscapes ◽  
Flying Squirrels ◽  
Preferred Habitat ◽  
Short Term Mortality ◽  
Pteromys Volans ◽  
Dispersal Distances ◽  
Near Future

In fragmented landscapes, dispersal abilities determine the potential of a species to colonize temporally unoccupied habitats. For example in territorial species, even the high-quality sites will be temporally unoccupied between the death of residents and recolonization by dispersers. This has implications for conservation management, because whether or not unoccupied habitats are worthy of protecting depends on likelihood that these sites will be recolonized in the near future. We analysed the ability of dispersing Siberian flying squirrels ( Pteromys volans (L., 1758)) to locate the preferred habitats. Dispersers encountered many patches of preferred habitat and, in the end, a majority of them successfully settled in these patches. The dispersal distance increased with increasing distance between patches, but settlement in preferred patches and short-term mortality were independent of dispersal distance or distance between available patches. We conclude that dispersers were effective in locating the preferred habitat in fragmented landscapes. Indeed, large interpatch distances partly explain that dispersal distances are longer in flying squirrels than usually observed in similar-sized mammals. For conservation management, our findings encourage managers to protect temporally unoccupied, high-quality habitats in addition to occupied habitats to promote a sustainable habitat network in space and time.

scholarly journals Antimicrobial defences increase with sociality in bees

2007 ◽  
Vol 3 (4) ◽  
pp. 422-424 ◽  
Author(s):  
Adam Stow ◽  
David Briscoe ◽  
Michael Gillings ◽  
Marita Holley ◽  
Shannon Smith ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Genetic Relatedness ◽  
Microbial Pathogens ◽  
Strongly Correlated ◽  
Social Species ◽  
Evolution Of Sociality ◽  
Selective Agents ◽  
Order Of Magnitude ◽  
Risk Of Disease ◽  
Solitary Species

Evidence for the antiquity and importance of microbial pathogens as selective agents is found in the proliferation of antimicrobial defences throughout the animal kingdom. Social insects, typified by crowding and often by low genetic variation, have high probabilities of disease transmission and eusocial Hymenoptera may be particularly vulnerable because of haplodiploidy. Mechanisms they employ to reduce the risk of disease include antimicrobial secretions which are particularly important primary barriers to infection. However, until now, whether or not there is selection for stronger antimicrobial secretions when the risk of disease increases because of sociality has not been tested. Here, we present evidence that the production of progressively stronger antimicrobial compounds was critical to the evolution of sociality in bees. We found that increases in group size and genetic relatedness were strongly correlated with increasing antimicrobial strength. The antimicrobials of even the most primitive semi-social species were an order of magnitude stronger that those of solitary species, suggesting a point of no return, beyond which disease control was essential. Our results suggest that selection by microbial pathogens was critical to the evolution of sociality and required the production of strong, front-line antimicrobial defences.

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