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121.
On the sustainability of common property resources 总被引:2,自引:0,他引:2
Nuria Oss-Eraso Montserrat Viladrich-Grau 《Journal of Environmental Economics and Management》2007,53(3):393-410
We provide a model where a common property resource is managed by two types of agents, cooperators and non-cooperators, who adjust their extraction strategies in response to persistent differential payoffs. In our model, the social approval of cooperators works as a reward mechanism which, as we show, favors both the pervasiveness of cooperative behavior and the sustainable management of natural resources. Specifically, we show that in the presence of such a reward mechanism a stable equilibrium can be reached with both strategies being practiced simultaneously and a decentralized and sustainable management of common property resources is possible. 相似文献
122.
?ystein?HolandEmail author Robert?B.?Weladji Hallvard?Gj?stein Jouko?Kumpula Martin?E.?Smith Mauri?Nieminen Knut?H.?R?ed 《Behavioral ecology and sociobiology》2004,57(1):69-76
In polygynous mammals, high-quality females may increase their fitness by providing superior care to their offspring. Based on the agonistic interactions of female reindeer in an experimental herd during two consecutive years (1997 and 1998), we tested whether maternal social rank influenced: (1) winter body-mass change of females, (2) preparturition reproductive effort (measured as fecundity, the birth mass and the birth date of their calves), (3) preweaning maternal effort (measured as calves preweaning mortality, early preweaning and late preweaning growth rate and September body mass of calves), and (4) postweaning maternal effort (measured as calves body-mass change during their first winter). In the models, we included September females body mass as a covariate to separate the effects of maternal rank and body mass. We also tested whether the effect of social rank on maternal efforts was dependent on offspring sex. High-ranked females gained body mass whereas low-ranked females lost weight during the winter. Fecundity was higher and date of birth was earlier in high-ranked females than in subordinates, whereas no effect of females rank on birth mass of calves was found. Early preweaning growth rate and September body mass of calves increased with increasing females social rank, whereas late preweaning daily growth rate of calves was not influenced by females rank. Calves preweaning mortality was only influenced by year, which also explained most of the variance in the winter body-mass change of calves. The effects of females rank on the reproductive-efforts parameters studied were not specific to offspring sex. These findings suggest that females rank influences reproductive effort during the preparturition, as well as the preweaning, period, the effect being sex independent.Communicated by R. Gibson 相似文献
123.
Cédric Alaux Malvina Boutot Pierre Jaisson Abraham Hefetz 《Behavioral ecology and sociobiology》2007,62(2):213-222
Worker sterility in the bumblebee Bombus terrestris is conditional and is linked to the social development of the colony. Workers refrain from reproducing or overtly challenging
the queen until gyne production has initiated, at the so-called competition point (CP). It is not known whether this behavior
is hard-wired or workers show reproductive plasticity. It also remains unclear whether worker reproductive decision is under
queen and/or worker control. In this study, we tested worker reproductive plasticity in an attempt to assess whether and under
which conditions worker sterility/fertility are reversible. We introduced egg-laying workers into colonies with different
social structures for 1 week then monitored their reproductive status. We revealed a remarkable reproductive plasticity in
the introduced workers that was social-condition-dependent. In the presence of a pre-CP queen, the introduced workers reverted
to sterility, whereas in the presence of a post-CP queen, such workers remained egg-layer. Reversion to sterility does not
occur when direct contact with the queen is prevented, as the introduced workers remained egg-layer in the queenright colonies
with a confined queen. Egg-laying workers that were introduced into queenless colonies mostly maintained their fertility regardless
of colony social phase. This shows that worker transition from cooperative to selfish behavior is reversible depending on
the social context. 相似文献
124.
Sociality in some birds, mammals, and social insects was suggested to have evolved through the lengthening and extension of
parental care behaviors to nondirect descendents. In these systems, group members care for young cooperatively and, thus,
increase the reproductive success of the breeders and fitness of the young. Parental care behaviors, such as regurgitation
feeding and matriphagy (consumption of the mother), occur in several subsocial and social spiders. However, it is not known
whether females in a colony cooperate in caring for the young of other females and whether such cooperative care improves
reproductive success. To answer this question, we created experimental colonies of the social spider Stegodyphus dumicola (Araneae, Eresidae), allowing only one female in a group to produce young, simulating reproductive skew occurring in nests
in nature. In this paper, we show for the first time that females of S. dumicola cooperate in providing regurgitated food for young of other females and are even eaten by those young. Young raised by a
group of females were larger and had greater survival than young raised only by their mother. Thus, fitness benefits from
raising broods cooperatively may have favored the evolution of sociality in spiders. 相似文献
125.
Brooke L. Sargeant Aaron J. Wirsing Michael R. Heithaus Janet Mann 《Behavioral ecology and sociobiology》2007,61(5):679-688
Because behavioral variation within and among populations may result from ecological, social, genetic and phenotypic differences,
identifying the mechanism(s) responsible is challenging. Observational studies typically examine social learning by excluding
ecological and genetic factors, but this approach is insufficient for many complex behaviors associated with substantial environmental
variation. Indian Ocean bottlenose dolphins (Tursiops sp.) in Shark Bay, Western Australia show individual differences in foraging tactics, including possible tool use with marine
sponges and social learning may be responsible for this diversity. However, the contributions of ecological factors to the
development of these foraging tactics were not previously investigated. Here, we determined the relationship between ecological
variables and foraging tactics and assessed whether differences in habitat use could explain individual differences in foraging
tactics. We monitored 14 survey zones to identify how foraging tactics were spatially distributed and matched behavioral data
to the ecological variables within each zone. Three of four foraging tactics were significantly correlated with ecological
characteristics such as seagrass biomass, water depth, presence of marine sponges and season. Further, individual differences
in habitat use were associated with some tactics. However, several tactics overlapped spatially and previous findings suggest
demographic and social factors also contribute to the individual variation in this population. This study illustrates the
importance of environmental heterogeneity in shaping foraging diversity and shows that investigating social learning by ruling
out alternative mechanisms may often be too simplistic, highlighting the need for methods incorporating the relative contributions
of multiple factors. 相似文献
126.
Piyamas Nanork Siriwat Wongsiri Benjamin P. Oldroyd 《Behavioral ecology and sociobiology》2006,61(1):91-97
Honeybee (Apis) workers cannot mate, but retain functional ovaries. When colonies have lost their queen, many young workers begin to activate their ovaries and lay eggs. Some of these eggs are reared, but most are not and are presumably eaten by other workers (worker policing). Here we explore some of the factors affecting the reproductive success of queenless workers of the red dwarf honeybee Apis florea. Over a 2-year period we collected 40 wild colonies and removed their queens. Only two colonies remained at their translocated site long enough to rear males to pupation while all the others absconded. Absconding usually occurred after worker policing had ceased, as evidenced by the appearance of larvae. Dissections of workers from eight colonies showed that in A. florea, 6% of workers have activated ovaries after 4 days of queenlessness, and that 33% of workers have activated ovaries after 3 weeks. Worker-laid eggs may appear in nests within 4 days and larvae soon after, but this is highly variable. As with Apis mellifera, we found evidence of unequal reproductive success among queenless workers of A. florea. In the two colonies that reared males to pupation and which we studied with microsatellites, some subfamilies had much higher proportions of workers with activated ovaries than others. The significance of absconding and internest reproductive parasitism to the alternative reproductive strategies of queenless A. florea workers is discussed. 相似文献
127.
Sean A. Rands Richard A. Pettifor J. Marcus Rowcliffe Guy Cowlishaw 《Behavioral ecology and sociobiology》2006,60(4):572-581
In socially foraging animals, it is widely acknowledged that the position of an individual within the dominance hierarchy of the group has a large effect upon its foraging behaviour and energetic intake, where the intake of subordinates can be reduced through socially mediated interference. In this paper, we explore the effects of interference upon group dynamics and individual behaviour, using a spatially explicit individual-based model. Each individual follows a simple behavioural rule based upon its energetic reserves and the actions of its neighbours (where the rule is derived from game theory models). We show that dominant individuals should have larger energetic reserves than their subordinates, and the size of this difference increases when either food is scarce, the intensity of interference suffered by the subordinates increases, or the distance over which dominant individuals affect subordinates increases. Unlike previous models, the results presented in this paper about differences in reserves are not based upon prior assumptions of the effects of social hierarchy and energetic reserves upon predation risk, and emerge through nothing more than a reduction in energetic intake by the subordinates when dominants are present. Furthermore, we show that increasing interference intensity, food availability or the distance over which dominants have an effect also causes the difference in movement between ranks to increase (where subordinates move more than dominants), and the distance over which dominants have an effect changes the size of the groups that the different ranks are found in. These results are discussed in relation to previous studies of intra- and interspecific dominance hierarchies. 相似文献
128.
Central-place foraging theory has been unable to explain the load selection behavior of leaf-cutting ants (Atta spp., Attini: Formicidae). We suggest that this is due to incomplete consideration of the sequence of behaviors involved in resource acquisition by these ants. Unlike most central-place foragers, leaf-cutting ants do not return to their nests with food. Instead, the leaf fragments they gather must be processed within the nest to convert them to substrate for fungal gardens. We have shown previously that leaf fragment size affects the rate of distribution and processing of leaf tissue inside laboratory nests of Atta colombica. Including these tasks in the calculation of foraging rate may help explain load selection and other features of central-place foraging by Atta colonies. Here we develop a mathematical model of the complete sequence of external and internal tasks that lead to addition of substrate to fungal gardens. Using realistic parameter values, the leaf fragment sizes predicted to maximize a colony's rate of foraging in this broad sense correspond well with the mean fragment sizes actually collected by Atta colonies in the field. The optimal fragment size for global performance in the model is below the size that would maximize the delivery rate by above-ground foragers. The globally optimal size also fails to maximize the rate of either fragment distribution or fragment processing within the nest. Our results show how maximum collective performance of an ensemble of linked tasks may require behavior that would appear suboptimal in a piecemeal analysis of tasks. 相似文献
129.
Control of reproduction in social insect colonies: individual and collective relatedness preferences in the paper wasp, Polistes annularis 总被引:1,自引:0,他引:1
David C. Queller J. M. Peters Carlos R. Solís Joan E. Strassmann 《Behavioral ecology and sociobiology》1997,40(1):3-16
Social insect colonies often have one or a few queens. How these queens maintain their reproductive monopoly, when other
colony members could gain by sharing in the reproduction, is not generally known. DNA microsatellite genotyping is used to
determine reproductive interests of various classes of colony members in the paper wasp, Polistes annularis. The relatedness estimates show that the best outcome for most individuals is to be the reproductive egg-layer. For workers,
this depends on the sex of offspring: they should prefer to lay their own male eggs, but are indifferent if the queen lays
the female eggs. The next-best choice is usually to support the current queen. As a rule, subordinates and workers should
prefer the current queen to reproduce over other candidates (though subordinates have no strong preference for the queen over
other subordinates, and workers may prefer other workers as a source of male eggs). This result supports the theory that reproductive
monopoly stems from the collective preferences of non-reproductives, who suppress each other in favor of the queen. However,
we reject the general hypothesis of collective worker control in this species because its predictions about who should succeed
after the death of the present queen are not upheld. The first successor is a subordinate foundress even though workers should
generally prefer a worker successor. If all foundresses have died, an older worker succeeds as queen, in spite of a collective
worker preference for a young worker. The results support the previous suggestion that age serves as a conventional cue serving
to reduce conflict over queen succession.
Received: 3 May 1996 / Accepted after revision: 22 September 1996 相似文献
130.
Robert E. Page Jr. Gene E. Robinson M. Kim Fondrk Medhat E. Nasr 《Behavioral ecology and sociobiology》1995,36(6):387-396
There have been numerous reports of genetic influences on division of labor in honey bee colonies, but the effects of worker genotypic diversity on colony behavior are unclear. We analyzed the effects of worker genotypic diversity on the phenotypes of honey bee colonies during a critical phase of colony development, the nest initiation phase. Five groups of colonies were studied (n = 5–11 per group); four groups had relatively low genotypic diversity compared to the fifth group. Colonies were derived from queens that were instrumentally inseminated with the semen of four different drones according to one of the following mating schemes: group A, 4 A-source drones; group B, 4 B-source drones; group C, 4 C-source drones; group D, 4 D-source drones; and group E, 1 drone of each of the A-D drone sources. There were significant differences between colonies in groups A-D for 8 out of 19 colony traits. Because the queens in all of these colonies were super sisters, the observed differences between groups were primarily a consequence of differences in worker genotypes. There were very few differences (2 out of 19 traits) between colonies with high worker genotypic diversity (group E) and those with low diversity (groups A-D combined). This is because colonies with greater diversity tended to have phenotypes that were average relative to colonies with low genotypic diversity. We hypothesize that the averaging effect of genotypic variability on colony phenotypes may have selective advantages, making colonies less likely to fail because of inappropriate colony responses to changing environmental conditions. 相似文献