scholarly journals Limited dispersal and an unexpected aggression pattern in a native supercolonial ant

2020 ◽  
Author(s):  
S. M. Hakala ◽  
M. Ittonen ◽  
P. Seppä ◽  
H. Helanterä
Keyword(s):  
Single Unit ◽  
Spatial Scales ◽  
Social Groups ◽  
Genetic Data ◽  
Clear Pattern ◽  
Aggressive Interactions ◽  
Limited Dispersal ◽  
Limited Gene Flow ◽  
Viscous Population ◽  
Cooperative Units

ABSTRACTUnderstanding how social groups function requires studies on how individuals move across the landscape and interact with each other. Ant supercolonies are extreme cooperative units that may consist of thousands of interconnected nests, and their individuals cooperate over large spatial scales. However, the inner structure of suggested supercolonial (or unicolonial) societies has rarely been extensively studied using both genetic and behavioral analyses. We describe a dense supercolony-like aggregation of more than 1 300 nests of the ant Formica (Coptoformica) pressilabris. We performed aggression bioassays and found that, while aggression levels were generally low, there was some aggression within the assumed supercolony. The occurrence of aggression increased with distance from the focal nest, in accordance with the genetically viscous population structure we observe by using 10 microsatellite markers. However, the aggressive interactions do not follow any clear pattern that would allow specifying colony borders within the area. The genetic data indicate limited gene flow within and away from the supercolony. Our results show that a Formica supercolony is not necessarily a single unit but can be a more fluid mosaic of aggressive and amicable interactions instead, highlighting the need to study internest interactions in detail when describing supercolonies.

scholarly journals Highly restricted dispersal in habitat-forming seaweed may impede natural recovery of disturbed populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florentine Riquet ◽  
Christiane-Arnilda De Kuyper ◽  
Cécile Fauvelot ◽  
Laura Airoldi ◽  
Serge Planes ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Spatial Scales ◽  
Mediterranean Ecosystems ◽  
Dispersal Distance ◽  
Genetic Connectivity ◽  
Restricted Gene Flow ◽  
Isolated Populations ◽  
Natural Recovery ◽  
Limited Dispersal ◽  
Ecological Importance

AbstractCystoseira sensu lato (Class Phaeophyceae, Order Fucales, Family Sargassaceae) forests play a central role in marine Mediterranean ecosystems. Over the last decades, Cystoseira s.l. suffered from a severe loss as a result of multiple anthropogenic stressors. In particular, Gongolaria barbata has faced multiple human-induced threats, and, despite its ecological importance in structuring rocky communities and hosting a large number of species, the natural recovery of G. barbata depleted populations is uncertain. Here, we used nine microsatellite loci specifically developed for G. barbata to assess the genetic diversity of this species and its genetic connectivity among fifteen sites located in the Ionian, the Adriatic and the Black Seas. In line with strong and significant heterozygosity deficiencies across loci, likely explained by Wahlund effect, high genetic structure was observed among the three seas (ENA corrected FST = 0.355, IC = [0.283, 0.440]), with an estimated dispersal distance per generation smaller than 600 m, both in the Adriatic and Black Sea. This strong genetic structure likely results from restricted gene flow driven by geographic distances and limited dispersal abilities, along with genetic drift within isolated populations. The presence of genetically disconnected populations at small spatial scales (< 10 km) has important implications for the identification of relevant conservation and management measures for G. barbata: each population should be considered as separated evolutionary units with dedicated conservation efforts.

scholarly journals The phone walkers: a study of human dependence on inactive mobile devices

Behaviour ◽  
2018 ◽  
Vol 155 (5) ◽  
pp. 389-414 ◽  
Author(s):  
Laura P. Schaposnik ◽  
James Unwin
Keyword(s):  
Mobile Devices ◽  
Mobile Phones ◽  
Census Data ◽  
Social Groups ◽  
Clear Pattern ◽  
Clear Tendency ◽  
Human Interactions ◽  
Opposite Sex ◽  
Significant Attention

Abstract The development of mobile phones has largely increased human interactions. Whilst the use of these devices for communication has received significant attention, there has been little analysis of more passive interactions. Through census data on casual social groups, this work suggests a clear pattern of mobile phones being carried in people’s hands, without the person using it (that is, not looking at it). Moreover, this study suggests that when individuals join members of the opposite sex there is a clear tendency to stop holding mobile phones whilst walking. Although it is not clear why people hold their phones whilst walking in such large proportions (38% of solitary women, and 31% of solitary men), we highlight several possible explanation for holding the device, including the need to advertise status and affluence, to maintain immediate connection with friends and family, and to mitigate feelings related to anxiety and security.

Demographic, dispersal, predation and genetic data reveal the potential vulnerability of an endangered rainforest shrub, Triunia robusta (Proteaceae)

2017 ◽  
Vol 65 (3) ◽  
pp. 270 ◽  
Author(s):  
Yoko Shimizu-Kimura ◽  
Scott Burnett ◽  
Alison Shapcott
Keyword(s):  
Gene Flow ◽  
Life Span ◽  
Demographic Data ◽  
Genetic Data ◽  
Seedling Mortality ◽  
Isolated Populations ◽  
Predation Mortality ◽  
Dispersal Vectors ◽  
Limited Gene Flow ◽  
Reproductive Rates

We investigated the population ecology of Triunia robusta (C.T. White) Foreman, an endemic rainforest shrub of south-east Queensland, Australia. Two-time demographic data from 1999 and 2010 were used to estimate the species life span and changes in demographic factors over the 11 year period. The potential dispersal vectors and their activities were monitored, and the effects of predation on seed and seedling mortality were quantified. Published genetic data was used to assess the gene flow distance in years. On average, T. robusta has a life span of 103 years, with a generation time of 44 years. Larger populations (>200) increased in size since 1999, whereas smaller populations retained the same or slightly reduced numbers. Small, isolated populations in the northern distribution range showed substantially lower reproductive rates. Local rodents and marsupials were considered responsible for the majority of observed secondary seed dispersal (<10.3 m) and predation activities. Post-predation mortality was high (82%), with only 12% surviving to become seedlings. The empirical evidence of short-distance dispersal, limited gene flow, high post-predation mortality rates and relatively low reproductive rates, combined with potential absence of primary dispersers suggests that critically small and isolated populations may be highly vulnerable.

Social choices in farm animals: to fight or not to fight?

1997 ◽  
Vol 20 ◽  
pp. 45-53 ◽  
Author(s):  
M. Mendl ◽  
H.W. Erhard
Keyword(s):  
Social Status ◽  
Social Groups ◽  
Farm Animals ◽  
Alternative Strategies ◽  
Aggressive Interactions ◽  
Fighting Ability ◽  
Young Pigs ◽  
Attack Latency ◽  
Free Ranging ◽  
Mixed Groups

AbstractFrom an animal production and welfare perspective, an important social choice made by farm animals is whether and how vigorously to fight others. The choice to fight (i.e. simultaneous escalated aggression by both contestants) may result in severe injury when unfamiliar animals first meet or compete for highly valued resources. Game theory models of aggressive interactions predict that animals have evolved to stop or avoid fighting when they assess their chances of winning a contest to be poor. Assessment may occur during or before a fight. If it occurs before a fight, reliable cues of fighting ability must exist. If farm animals can establish relative social status by assessment prior to fighting, it may be possible to construct social groups which contain individuals of differing abilities such that most disputes are resolved through assessment and levels of damaging aggression are kept low. Social status appears to be established by assessment rather than fighting in free-ranging deer and sheep when asymmetries exist in reliable cues of their fighting abilities such as roaring rate and horn size. However, there have been few detailed studies of other farmed species and findings are equivocal. Work on young pigs suggests that, in pair-wise encounters, individuals are unable to assess weight-related asymmetries in their abilities without fighting. However, recent studies of groups of pigs suggest that some form of assessment prior to fighting may occur. Individuals were classified as high (H) or low (L) aggressive on the basis of their behaviour in an attack latency test. When litters of H pigs were mixed with litters of L pigs, significantly fewer pairs of unfamiliar pigs fought than when newly mixed groups were made up of litters of H pigs only, or litters of L pigs only. Thus, fighting was least frequent when there was a marked asymmetry in the aggressiveness of unfamiliar individuals. Another study raised the possibility that H and L pigs may be following alternative strategies which, under certain circumstances, are similarly beneficial in welfare and production terms. Further work is required to substantiate these findings and to determine whether aggressiveness is a reliable cue of fighting ability and, if so, how it is manifest and assessed.

scholarly journals Isolation by resistance across a complex coral reef seascape

2015 ◽  
Vol 282 (1812) ◽  
pp. 20151217 ◽  
Author(s):  
Luke Thomas ◽  
W. Jason Kennington ◽  
Michael Stat ◽  
Shaun P. Wilkinson ◽  
Johnathan T. Kool ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Divergence ◽  
Larval Dispersal ◽  
Population Genetic ◽  
Spatial Genetic Structure ◽  
Spatial Scales ◽  
Genetic Data ◽  
Genetic Structure Of Populations ◽  
Seascape Genetics

A detailed understanding of the genetic structure of populations and an accurate interpretation of processes driving contemporary patterns of gene flow are fundamental to successful spatial conservation management. The field of seascape genetics seeks to incorporate environmental variables and processes into analyses of population genetic data to improve our understanding of forces driving genetic divergence in the marine environment. Information about barriers to gene flow (such as ocean currents) is used to define a resistance surface to predict the spatial genetic structure of populations and explain deviations from the widely applied isolation-by-distance model. The majority of seascape approaches to date have been applied to linear coastal systems or at large spatial scales (more than 250 km), with very few applied to complex systems at regional spatial scales (less than 100 km). Here, we apply a seascape genetics approach to a peripheral population of the broadcast-spawning coral Acropora spicifera across the Houtman Abrolhos Islands, a high-latitude complex coral reef system off the central coast of Western Australia. We coupled population genetic data from a panel of microsatellite DNA markers with a biophysical dispersal model to test whether oceanographic processes could explain patterns of genetic divergence. We identified significant variation in allele frequencies over distances of less than 10 km, with significant differentiation occurring between adjacent sites but not between the most geographically distant ones. Recruitment probabilities between sites based on simulated larval dispersal were projected into a measure of resistance to connectivity that was significantly correlated with patterns of genetic divergence, demonstrating that patterns of spatial genetic structure are a function of restrictions to gene flow imposed by oceanographic currents. This study advances our understanding of the role of larval dispersal on the fine-scale genetic structure of coral populations across a complex island system and applies a methodological framework that can be tailored to suit a variety of marine organisms with a range of life-history characteristics.

scholarly journals Development and application of 14 microsatellite markers in the burying beetle Nicrophorus vespilloides reveals population genetic differentiation at local spatial scales

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3278 ◽  
Author(s):  
Sonia Pascoal ◽  
Rebecca M. Kilner
Keyword(s):  
Genetic Differentiation ◽  
Microsatellite Markers ◽  
Parental Care ◽  
Social Evolution ◽  
Spatial Scales ◽  
Burying Beetle ◽  
Genetic Structuring ◽  
Population Genetic Differentiation ◽  
Nicrophorus Vespilloides ◽  
Limited Dispersal

Burying beetles (genus Nicrophorus) are relatively rare among insects in providing sophisticated parental care. Consequently, they have become model species in research analysing social evolution, the evolution of parental care and mating systems. We used the recently published N. vespilloides genome and transcriptome to develop microsatellite markers. Specifically, we developed 14 polymorphic markers with five to 13 alleles per locus and used them to investigate levels of genetic differentiation in four south Cambridgeshire (UK) populations of N. vespilloides, separated by 21 km at most. The markers revealed significant genetic structuring among populations (global FST = 0.023) with all but one of the pairwise comparisons among populations being significant. The single exception was the comparison between the two closest populations, which are approximately 2.5 km apart. In general, the microsatellite markers showed lower observed heterozygosity than expected. We infer that there is limited dispersal between populations and potentially also some inbreeding within them and suggest that this may be due to habitat fragmentation. We discuss these results in the context of recent laboratory experiments on inbreeding and beetle flight.

scholarly journals Population structure and dispersal across small and large spatial scales in a direct developing marine isopod

2020 ◽  
Author(s):  
William S. Pearman ◽  
Sarah J. Wells ◽  
Olin K. Silander ◽  
Nikki E. Freed ◽  
James Dale
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Population Genetic ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Population Connectivity ◽  
Clear Pattern ◽  
Small Spatial Scale ◽  
Cook Strait ◽  
Genetic Break

AbstractMarine organisms generally exhibit one of two developmental modes: biphasic, with distinct adult and larval morphology, and direct development, in which larvae resemble adults. Developmental mode is thought to significantly influence dispersal, with direct developers expected to have much lower dispersal potential. However, in contrast to our relatively good understanding of dispersal and population connectivity for biphasic species, comparatively little is known about direct developers. In this study, we use a panel of 8,020 SNPs to investigate population structure and gene flow for a direct developing species, the New Zealand endemic marine isopod Isocladus armatus. On a small spatial scale (20 kms), gene flow between locations is extremely high and suggests an island model of migration. However, over larger spatial scales (600km), populations exhibit a clear pattern of isolation-by-distance. Because our sampling range is intersected by two well-known biogeographic barriers (the East Cape and the Cook Strait), our study provides an opportunity to understand how such barriers influence dispersal in direct developers. Our results indicate that I. armatus exhibits significant migration across these barriers, and suggests that ocean currents associated with these locations do not present a barrier to dispersal. Interestingly, we do find evidence of a north-south population genetic break occurring between Māhia and Wellington, two locations where there are no obvious biogeographic barriers between them. We conclude that developmental life history largely predicts dispersal in intertidal marine isopods. However, localised biogeographic processes can disrupt this expectation.

scholarly journals The integrity of crime statistics: Assessing the impact of police data bias on crime mapping

2020 ◽  
Author(s):  
David Buil-Gil ◽  
Angelo Moretti ◽  
Samuel Langton
Keyword(s):  
Spatial Scales ◽  
Social Groups ◽  
Relative Difference ◽  
Small Areas ◽  
Police Data ◽  
Measures Of Dispersion ◽  
Micro Level ◽  
The Uk ◽  
Reporting Rates ◽  
The Impact

Police-recorded crimes are used by police forces to map crime patterns and design spatially-targeted strategies. Nevertheless, maps of crimes known to police are affected by selection biases driven by unequal crime reporting rates across social groups. This paper presents a simulation study to analyse the impact of selection biases on crime maps produced at different spatial scales. Based on parameters obtained from the UK Census, we simulate a synthetic population consistent with the characteristics of Manchester. Then, based on parameters derived from the Crime Survey for England and Wales, we simulate crimes suffered by individuals, and their likelihood to be known to police. This allows comparing the relative difference between all crimes and police-recorded incidents at the different spatial scales. While the average relative difference between all crimes and those known to police is 62% across all geographical scales, the measures of dispersion of the relative difference are larger when crimes are aggregated to small geographies. The percentage of crimes unknown to police varies widely across small areas, underestimating the prevalence of crime in certain places while overestimating it in others. Micro-level crime maps are affected by a larger risk of bias than maps produced at larger scales.

scholarly journals Single-unit activity, threshold crossings, and local field potentials in motor cortex differentially encode reach kinematics

2015 ◽  
Vol 114 (3) ◽  
pp. 1500-1512 ◽  
Author(s):  
Sagi Perel ◽  
Patrick T. Sadtler ◽  
Emily R. Oby ◽  
Stephen I. Ryu ◽  
Elizabeth C. Tyler-Kabara ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Local Field ◽  
Unit Activity ◽  
Single Unit ◽  
Primary Motor Cortex ◽  
Spatial Scales ◽  
Local Field Potentials ◽  
Single Unit Activity ◽  
Field Potentials ◽  
Threshold Crossing

A diversity of signals can be recorded with extracellular electrodes. It remains unclear whether different signal types convey similar or different information and whether they capture the same or different underlying neural phenomena. Some researchers focus on spiking activity, while others examine local field potentials, and still others posit that these are fundamentally the same signals. We examined the similarities and differences in the information contained in four signal types recorded simultaneously from multielectrode arrays implanted in primary motor cortex: well-isolated action potentials from putative single units, multiunit threshold crossings, and local field potentials (LFPs) at two distinct frequency bands. We quantified the tuning of these signal types to kinematic parameters of reaching movements. We found 1) threshold crossing activity is not a proxy for single-unit activity; 2) when examined on individual electrodes, threshold crossing activity more closely resembles LFP activity at frequencies between 100 and 300 Hz than it does single-unit activity; 3) when examined across multiple electrodes, threshold crossing activity and LFP integrate neural activity at different spatial scales; and 4) LFP power in the “beta band” (between 10 and 40 Hz) is a reliable indicator of movement onset but does not encode kinematic features on an instant-by-instant basis. These results show that the diverse signals recorded from extracellular electrodes provide somewhat distinct and complementary information. It may be that these signal types arise from biological phenomena that are partially distinct. These results also have practical implications for harnessing richer signals to improve brain-machine interface control.

Low frequency traveling waves in the human cortex coordinate neural activity across spatial scales

2020 ◽  
Author(s):  
Vishnu Sreekumar ◽  
John H. Wittig ◽  
Julio Chapeton ◽  
Sara K. Inati ◽  
Kareem A. Zaghloul
Keyword(s):  
Temporal Lobe ◽  
Traveling Waves ◽  
Verbal Memory ◽  
Single Unit ◽  
Spatial Scales ◽  
Memory Task ◽  
Low Frequency ◽  
Oscillatory Activity ◽  
Neural Communication ◽  
Macro Scale

AbstractTraveling waves of oscillatory activity are thought to influence neuronal spiking, providing a spatiotemporal frame-work for neural communication. However, no direct link has been established between traveling waves and single unit spiking in humans. We examined traveling waves in the human lateral temporal lobe by using recordings from intracranial electrodes implanted in twenty participants for seizure monitoring as they performed a paired-associates verbal memory task. We observed ubiquitous low frequency traveling waves across the temporal lobe. While wave occurrence in a broad low frequency range did not differ between successful and unsuccessful memory conditions, in a subset of participants with microelectrode recordings, we found that macro-scale waves co-occurred with micro-scale waves, which in turn were temporally locked to single unit spiking. This temporal coordination between traveling waves at different spatial scales and between waves and neuronal spiking in the human brain suggests a role for traveling waves in neural communication.

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