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1.
N. Rashevsky 《Bulletin of mathematical biology》1950,12(3):177-185
In previous publications, social groups have been studied in which each individual has a preference for one of two possible
mutually exclusive activities. This preference is measured by a quantity ϕ. The value ϕ=0 corresponds to no preference; a
preference for one activity is measured by a positive ϕ, the preference for the other by a negative ϕ. The quantity ϕ varies
from individual to individual. It has been shown previously that, owing to effects of imitation, even when the average ϕ for
the group is zero, one of the two behaviours will be chosen by the majority of the group. Whereas in previous studies the
imitation effect was considered as independent of the distance between the imitating and imitated individuals, in the present
study the case is considered in which the effect of imitation decreases with the distance between the individuals. It is found
that under certain conditions a greater percentage near the center of the area occupied by the group, rather than near the
periphery, exhibits the chosen behavior. The possible sociological meaning of this gradient of behavior is discussed. 相似文献
2.
George Wittemyer John B. A. Okello Henrik B. Rasmussen Peter Arctander Silvester Nyakaana Iain Douglas-Hamilton Hans R. Siegismund 《Proceedings. Biological sciences / The Royal Society》2009,276(1672):3513-3521
Hierarchical properties characterize elephant fission–fusion social organization whereby stable groups of individuals coalesce into higher order groups or split in a predictable manner. This hierarchical complexity is rare among animals and, as such, an examination of the factors driving its emergence offers unique insight into the evolution of social behaviour. Investigation of the genetic basis for such social affiliation demonstrates that while the majority of core social groups (second-tier affiliates) are significantly related, this is not exclusively the case. As such, direct benefits received through membership of these groups appear to be salient to their formation and maintenance. Further analysis revealed that the majority of groups in the two higher social echelons (third and fourth tiers) are typically not significantly related. The majority of third-tier members are matrilocal, carrying the same mtDNA control region haplotype, while matrilocality among fourth-tier groups was slightly less than expected at random. Comparison of results to those from a less disturbed population suggests that human depredation, leading to social disruption, altered the genetic underpinning of social relations in the study population. These results suggest that inclusive fitness benefits may crystallize elephant hierarchical social structuring along genetic lines when populations are undisturbed. However, indirect benefits are not critical to the formation and maintenance of second-, third- or fourth-tier level bonds, indicating the importance of direct benefits in the emergence of complex, hierarchical social relations among elephants. Future directions and conservation implications are discussed. 相似文献
3.
Vanessa B. Fortes Júlio César Bicca-Marques 《International journal of primatology》2008,29(3):717-722
We located 4 brown howlers (1 adult male, 2 adult females, and 1 juvenile male) showing abnormally lighter pelage in 3 social
groups comprising 5, 6, and 9 individuals in a 20 ha-forest fragment in the State of Rio Grande do Sul, Brazil. Two additional
groups composed only of normally colored individuals also live in the fragment, which is isolated from nearby fragments by
267–1009 m. They were the only brown howlers with abnormal pelage color out of a total of 386 individuals belonging to 67
groups in 21 fragments in the 5876-ha study area. The isolation of the forest fragment, its high howler density (2.2 individuals⁄ha),
and large group size (8.8 ± 2.4 individuals) may decrease the likelihood of successful immigration into the population, leading
to an increased probability of inbreeding that may facilitate the expression of rare alleles. 相似文献
4.
N. Rashevsky 《Bulletin of mathematical biology》1952,14(2):193-201
Progress in social and cultural life is initiated by a small group of individuals, who do not follow the socially accepted
habits, patterns of behavior, or ideas. Such individuals may be conveniently called nonconformists. The rate of cultural progress
depends largely on their number. This number is partly determined by purely biological factors, which result in a certain
fraction of individuals being born with the necessary predisposition. Partly, it is determined by the circumstance that the
progeny of nonconformists is reared and educated in nonconformist behavior. This latter process requires the possibility for
the existing nonconformists to gather together and to form semi-closed social groups. This, in turn, depends to a large extent
on the rate of urbanization of the population, which is affected by various environmental factors.
Mathematical expressions are developed which show how these different environmental factors affect the growth of the number
of nonconformists, and thus affect the rate of cultural changes. Some very general comparisons with known facts indicate the
possibility of future applications of the theory.
The principal result of the study is the fact that social groups with identical biological characteristics may show a great
difference in cultural development due to differences in environment. 相似文献
5.
Sussie Pagh June Buxbom Mariann Chril Cino Pertoldi Jes Se Pedersen Mette Sif Hansen 《Acta theriologica》2020,65(2):215-222
The population of raccoon dogs (Nyctereutes procyonoides) in Denmark has increased rapidly from 1995 when the first was recorded until today where 3291 raccoon dogs are trapped, shot by hunters or road killed. The aims of this study are to present the first data on reproduction and life tables of raccoon dogs in Denmark and to compare mortality from modelled life tables with game bag records and sampled raccoon dogs in different age groups. In this study, the uteri of 89 adult females (> 10 months) were examined for placental scars (PSC), and 561 individuals (289 males, 272 females) were aged using pulp cavity width and dental lines in canine teeth. The litter size of raccoon dogs in Denmark is to date the largest litter size recorded in the wild (mean ± SE) 10.8 ± 0.4, range 1–16 pubs and fecundity 8.4 ± 0.6 pubs. The percent-reproducing females are 78–83%, based on dark and all PSC, respectively. A significant difference was found between the proportion of individuals composing the different age groups based on age determination of individuals collected (Ntage) and the modelled number of individuals in age groups based on fecundity and different mortality rate (Ntmodel), X2 = 8, p < 0.05. The discrepancy between the relatively high reproduction and lifetables may be due to older and more experienced animals that avoid culling. A low population density in a newly founded Danish population of raccoon dogs, together with a milder climate where raccoon dogs can forage during the winter, may cause an exceptionally high reproduction in Danish raccoon dogs. 相似文献
6.
We observed a case of infant adoption in an unprovisioned group of wild black-fronted titi monkeys (Callicebus nigrifrons). During our long-term field study we noticed that an infant had moved from one of our study groups (“Desbotado”) to another
(“Rio”). Observations of the adoptive group confirm that it was being cared for by the adult male, and initially the group’s
adult female was nursing the infant alongside her biological infant. Interestingly, the native and adoptive groups have frequent
inter-group interactions, but at no point have we observed the native group trying to retrieve its infant. As of April 2007
the infant has been living in its adoptive group for 19 months. These data document the first case of adoption in this genus;
they suggest that infant recognition is poorly developed in this species and that under certain circumstances wild groups
of C.
nigrifrons can successfully rear twins. In our study population reproductive females give birth to one infant every year; the only case
when this has not happened is with the group that adopted the infant, suggesting that adoption may generate a reproductive
cost. 相似文献
7.
V. Konduri I. D. Godwin C. J. Liu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(6):866-871
A linkage map of Lablab purpureus consisting of 127 RFLP and 91 RAPD loci was constructed in an F2 population of 119 individuals. This population was derived from a cross between ’Rongai’ (an annual cultivar) and CPI 24973
(a perennial wild accession). The map comprises 17 linkage groups and covers 1610 centiMorgans (cM) with an average distance
of 7 cM between markers. Severe segregation distortions were observed, with the very extreme situation where no paternal type
was recovered from the mapping population. These results strongly suggest the presence of a gene conferring preferential transmission
from the maternal parent ’Rongai’. It was also clear that, while the majority of RAPD markers are valuable when used together
with RFLP or other stringent marker systems, they could be problematic when used solely in mapping exercises.
Received: 20 April 1999 / Accepted: 23 August 1999 相似文献
8.
K. R. Fialkowski 《Human Evolution》1990,5(2):153-166
It is claimed that a social group of unrelated individuals specialized in performing different tasks is specifically human
and has no analogy in the animal kingdom. Among animals only some insects of two orders, Isoptera (termites) and Hymenoptera
(wasps, bees and ants) live in social groups of individuals performing specialized tasks, but those, individuals are related.
For all social groups of individuals specialized in tasks, average fitness drops close to nil when the group disintegrates.
It is not, however, a continuous decrease of fitness leading to smaller but still high values when the group disintegrates
but rather a discrete switch of the average fitness; from a high value to close to nil.
In groups consisting of related individuals maximization of inclusive fitness constitutes a mechanism sufficient to support
the existence of such groups. Only in the case of the human (unrelated) group, to maintain the group and high fitness of its
individuals, a non-reciprocal altruistic approach of an individual had to be displayed to all members of the group (regardless
of relatedness). Since strategies resulting from the altruistic approach contradicted the genetically programmed strategies,
moral codes were introduced to suppress the latter.
This non-reciprocal altruism to any member of the group is in fact equivalent to the reciprocal “altruism” to an abstract
entity called system group and is unique to the human.
Altruism is considered here as a component of the meta-trait of culture. 相似文献
9.
N. Rashevsky 《Bulletin of mathematical biology》1949,11(3):157-163
A group of individuals is considered in which each individual has tendencies to exhibit one or another of two mutually exclusive
behaviors. Neurobiophysically this may be described in terms of Landahl's reciprocally inhibited parallel reaction chains.
The spontaneous excitations ε1 and ε2 at the central connections of each chain are a measure of the “natural” tendency of the individual toward one or the other
of the two behaviors. According to equations derived by H. D. Landahl, the probability of one or the other behavior is determined
by the difference ε1 − ε2. A population of individuals is considered in which ε1 − ε2 is distributed in some continuous way, and therefore in which the probability of a given behavior is distributed continuously
between 0 and 1. The effect of other individuals exhibiting a given behavior is to increase the corresponding ε of the individual.
Thus behavior of others affects the probability for a given behavior of each individual. It is shown that the equations describing
the behavior of the population on the basis of this neurobiophysical picture reduce in the first approximation to the differential
equations which were postulated by the author in his previous work on social behavior. 相似文献
10.
A G Fix 《American journal of physical anthropology》1975,43(2):295-302
Analysis of histories and genealogies from seven relatively unacculturated, swidden-farming Semai settlements shows that the composition of local groups fluctuates through time. This instability is similar to a pattern which Neel and his colleagues have suggested is typical of primitive society, the fission-fusion model. In addition, the individuals comprising Semai fission groups are kinsmen which implies that the number of independent genomes represented is markedly less than the number of individual migrants (the lineal effect). Fission groups may form new villages or fuse with an established settlement. In either case, the genetic effects of such migration are more pronounced than would be expected on the basis of founder effect or random migration. Despite several conspicuous differences in social organization between the Semai and the South American Indians (e.g., bilateral vs. unilineal descent) whose population structure provided the empirical basis for the fission-fusion, lineal effect model, the basic similarities are striking. The Semai case thus lends support to the proposition that this pattern may be of some generality in technologically primitive populations. 相似文献
11.
Food availability is important to the dynamics of animal social organizations or populations. However, the role of winter
food availability in animal population dynamics is still controversial. We carried out an experimental study to test Lack’s
hypothesis that reduced food in winter limits survival and spring numbers of breeding individuals of social groups, using
the Mongolian gerbil (Meriones unguiculatus) as model species. We established 24 gerbil social groups in 24, 10 × 10 m, pens in September 2008. We provided wheat seeds
as supplemental food in 12 enclosures from September 2008 to March 2009; the other 12 enclosures, not provided with supplemental
food, served as controls. We live-trapped gerbils at a 2-week interval from September to April. Supplemental food during winter
increased biweekly survival by 10% relative to that in control groups. Only four control social groups survived to the end
of our study whereas all 12 food-supplemented social groups survived through our study period. Supplemental food also increased
cumulative numbers of recruits and group sizes of gerbils. We conclude that winter food availability limits winter survival
and spring social groups or population sizes of Mongolian gerbils. 相似文献
12.
We investigated the reproductive system of the threatened taxon Dombeya acutangula ssp. acutangula Cav. (Sterculiaceae), an endemic tree of the Mascarene archipelago (Indian Ocean). A controlled crossing experiment was performed
in two natural populations located in the remnants of the low-elevation dry forest on the island of La Réunion. Active pollination,
probably mainly by insects, was necessary for reproduction in this species. Individuals varied in their degree of self-sterility
from 0 to 100%. Outcrossing between nearby individuals produced lower seed set than did crosses between more distant individuals
within one of the two tested populations. The variation in reproductive success on selfing and in the different types of crosses
could result from inbreeding depression causing embryo death, and we provide evidence that progenies from selfing have lower
seed size and quality. However, for inbreeding depression to account for the dramatic variation in seed set found in our crossing
experiment, the distribution of genetic load and number of lethal factors required appear unrealistic. We favour an alternative
interpretation, that D. acutangula possesses an incompatibility system similar to that found in other Sterculiaceae species such as Theobroma cacao L. Such an incompatibility system allows a certain amount of selfing, and different individuals vary in their degree of self-incompatibility.
The low success of crosses among close neighbours in one population suggests that there was spatial structure for incompatibility
alleles in that population. This could partly explain the decline of the species in fragmented and disturbed habitats, since
relatedness at incompatibility loci may increase in small or isolated population and thus reduce mate availability.
Received: 2 March 1998 / Accepted: 3 August 1998 相似文献
13.
This article traces a critical change in the professional therapy of posttraumatic stress disorder (PTSD): from treatment
of a disorder borne by individuals to treatment of an anticipated disorder to be prevented by fortifying the entire population.
A community resilience program in the city of Sderot in southern Israel, which has been subjected to Qassam rockets by its
Palestinian neighbors across the border, serves as our case study. Drawing on an ethnographic study of this new therapeutic
program, we analyze how the social body that the professionals attempt to immunize against trauma was treated. In particular,
we follow the various practices used to expand the clinical. We found that the population was split into several groups on
a continuum between the clinical and the preclinical, each receiving different treatment. Moreover, the social body managed
according to this new form of PTSD was articulated through ethnic and geopolitical power relations between professionals from
the country’s center and professionals from its periphery, and between the professionals and the city’s residents. Finally,
we discuss how this Israeli case compares with other national sites of the growing globalization of PTSD, like Bali, Haiti
and Ethiopia, which anthropologists have been exploring in recent years. 相似文献
14.
Individual’s decisions, from what product to buy to whether to engage in risky behavior, often depend on the choices, behaviors, or states of other people. People, however, rarely have global knowledge of the states of others, but must estimate them from the local observations of their social contacts. Network structure can significantly distort individual’s local observations. Under some conditions, a state that is globally rare in a network may be dramatically over-represented in the local neighborhoods of many individuals. This effect, which we call the “majority illusion,” leads individuals to systematically overestimate the prevalence of that state, which may accelerate the spread of social contagions. We develop a statistical model that quantifies this effect and validate it with measurements in synthetic and real-world networks. We show that the illusion is exacerbated in networks with a heterogeneous degree distribution and disassortative structure. 相似文献
15.
Sharon Gursky 《International journal of primatology》2010,31(1):117-131
One of the most widely accepted explanations for the difference in the sex bias between mammals and birds is that male-biased
dispersal in mammals is due to the preponderance of polygynous mating systems exhibited by this class, whereas birds are predominantly
monogamous. Spectral tarsiers (Tarsius spectrum) are unusual in that they exhibit variation in its mating system. Although the majority of spectral tarsier groups are monogamous,
ca. 15% are polygynous. If mating system influences dispersal, then I predicted that the polygynous groups would exhibit male
biased dispersal whereas I predicted that the dispersal patterns of the monogamous groups would be analogous to that exhibited
by birds, specifically female biased. Alternatively, I hypothesized that ecological variation may influence dispersal habits
in this species. Specifically, I predicted that polygynous groups would exhibit greater habitat quality than monogamous groups.
The 2 hypotheses are not mutually exclusive. On the basis of 14 individuals birdbanded between 1994 and 1999, I determined
that individuals of both sexes were equally likely to disperse (males, n = 5; females, n = 9). Males dispersed twice as far as females did. The mean dispersal distance for males was 660 m, and for females it was
266 m. Females (77%) were more likely to form a territory adjacent to the parental territory than were males (20%). Individuals
exhibited relatively high amounts of site fidelity (86%) that were related to physical characteristics of the sleeping site.
Adults that dispersed a second time (n = 4) initially resided in trees that were shorter and had a smaller diameter-at-breast height than the trees of individuals
that exhibited site fidelity. The results of my study partly support the parental mating system hypothesis and also support
the habitat quality hypothesis. 相似文献
16.
Gibbons are among the best-studied Asian primates, but few studies address their demography and life history strategies. We
used annual censuses to study the demography of agile gibbons (Hylobates agilis) between 1998 and 2009 in rain forests of Bukit Barisan Selatan National Park, Indonesia. The population declined from 22
individuals (9 groups) to 14 individuals (5 groups) over the 12 yr of study. Infant survival to the juvenile age class was
33.3%, and 16.7% of infants survived to the subadult age class. The interbirth interval was 3.83 ± 1.15 yr and birth rate
was 0.22–0.28 infants female–1 yr–1. Two groups colonized the study area but subsequently disappeared. We documented 7 immigrations, 17 disappearances, and ≥10
transients in the population. Compared to lar gibbons (Hylobates lar) and Bornean white-bearded gibbons (Hylobates albibarbis), Way Canguk’s agile gibbon population is characterized by slow reproduction, low survival, and high group turnover. We hypothesize
that, although the habitat is high in fruit resources, agile gibbons may be displaced or excluded from the best fruit resources
by larger and more numerous competitors, incurring costs of decreased opportunities to forage and increased travel, and leading
to higher mortality for young agile gibbons. The reproductive potential of this agile gibbon population is insufficient to
compensate for high mortality, and the population is unlikely to persist without immigration from outside the area. Given
the agile gibbons’ endangered status and limited capacity to respond demographically to change, it is likely that intensive
management interventions will be required to conserve this species. 相似文献
17.
Yoshikazu Ueno 《Journal of Ethology》1994,12(2):81-87
When the tufted capuchin urinates, it frequently performs “urine-washing”. Previous studies have proposed several hypotheses
about this behavior. This study investigated 1) whether the tufted capuchin can distinguish the urine odor of conspecific
individuals from other groups, and 2) whether the capuchins can distiguish conspcific urine odor of from that of other species.
When an odor bar that had been prepared in conspecific other group's cage was presented, the response (sniffing, licking,
or biting) was significantly greater than that to any other odors, including that of the home group, 5 other species, or a
neutral odor. This tendency was stronger in males than in females. and suggests that the tufited capuchin is able to discriminate
its home group's urine odor from that of the other groups. This monkey may also discriminate its own species from others by
urine odor. The sex difference of the response to the odor bar may be the result of differences in social role between males
and females. These results support the idea that the tufted capuchin may use olfaction for social communication. 相似文献
18.
Sarah Edwards Jenny Noack Louis Heyns Diethardt Rodenwoldt L Max Tarjan 《Acta theriologica》2020,65(2):223-233
Understanding the spatial ecology of wildlife is an essential prerequisite for making informed management decisions and is of particular importance for those species residing in enclosed reserves where space use may be influenced by restricted dispersal and high population densities. As the brown hyaena Parahyaena brunnea is a species likely to increasingly rely on enclosed protected areas for its long-term persistence, due to the intense persecution experienced outside of protected areas, we examined the spatial ecology of 10 brown hyaenas from a high-density population, within a small (200 km2) enclosed reserve in north-central Namibia. Spatial data, in combination with camera trap data from communal den sites, suggested six clans and at least one nomadic individual in the reserve. A mean home range size of 37 km2 (± 21 km2, range 16–97 km2) was recorded, with 92% of the reserve utilized as brown hyaena home range. Whilst these home range sizes are some of the lowest recorded for brown hyaena, the degree of overlap between neighbouring clans was similar to that recorded for open systems. Given that the majority of the reserve is utilized as brown hyaena home range, options for dispersing subadults may be limited and these individuals may represent ideal candidates for translocation into other enclosed reserves as part of metapopulation management schemes. 相似文献
19.
Kinship in colonial tuco-tucos: evidence from group composition and population structure 总被引:2,自引:1,他引:1
Kinship plays a significant role in shaping the social and geneticstructures of many vertebrate populations. Evidence of kinship,however, may be substantially influenced by the spatial andtemporal scales over which co-ancestry is monitored. For example,while data on social group composition may yield little indicationof relatedness among reproductive partners, data on the demographicstructure of a population may reveal considerable shared ancestryamong mates. We explored relationships among social group composition,individual movements, and population-level patterns of kinshipusing data from a 7-year field study of the colonial tuco-tuco(Ctenomys sociabilis), a group-living subterranean rodent thatis endemic to southwestern Argentina. Our analyses indicatethat social groups are composed of 14 generations ofclosely related females and a single, immigrant male, suggestingthat reproductive partners are not related to one another. Monitoringindividual movements, however, revealed that (1) most male dispersaloccurs within the local population and (2) most new social groupsare founded by females born in the study population, indicatingthat individuals reared in different burrow systems may shareconsiderable co-ancestry. Simulation analyses revealed thatup to 67% of reproductive partnerships consist of animals thatshare co-ancestry within the last 57 generations. Thus,while analyses of social group composition provide little evidenceof kinship among reproductive partners, population-level analysesof dispersal and group formation suggest that co-ancestry amongmates is common. These findings have important implicationsfor interpreting social interactions and genetic structure inthis species. 相似文献
20.
Previous game theoretical analyses of vaccinating behaviour have underscored the strategic interaction between individuals
attempting to maximise their health states, in situations where an individual's health state depends upon the vaccination
decisions of others due to the presence of herd immunity. Here, we extend such analyses by applying the theories of variational
inequalities (VI) and projected dynamical systems (PDS) to vaccination games. A PDS provides a dynamics that gives the conditions
for existence, uniqueness and stability properties of Nash equilibria. In this paper, it is used to analyse the dynamics of
vaccinating behaviour in a population consisting of distinct social groups, where each group has different perceptions of
vaccine and disease risks. In particular, we study populations with two groups, where the size of one group is strictly larger
than the size of the other group (a majority/minority population). We find that a population with a vaccine-inclined majority
group and a vaccine-averse minority group exhibits higher average vaccine coverage than the corresponding homogeneous population,
when the vaccine is perceived as being risky relative to the disease. Our model also reproduces a feature of real populations:
In certain parameter regimes, it is possible to have a majority group adopting high vaccination rates and simultaneously a
vaccine-averse minority group adopting low vaccination rates. Moreover, we find that minority groups will tend to exhibit
more extreme changes in vaccinating behaviour for a given change in risk perception, in comparison to majority groups. These
results emphasise the important role played by social heterogeneity in vaccination behaviour, while also highlighting the
valuable role that can be played by PDS and VI in mathematical epidemiology. 相似文献