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481.
Michael Hrncir Sidnei Mateus Fábio S. Nascimento 《Behavioral ecology and sociobiology》2007,61(6):975-983
An efficient exploitation of carbohydrate food sources would be beneficial for social wasp species that store nectar within
their nest. In the swarm-founding polistine wasp Polybia occidentalis, we now demonstrate that the decisions of when and where to forage are influenced by information from conspecifics. Only
when foragers had been trained to collect at artificial carbohydrate feeders did newcomers (food-source-naive individuals)
continuously arrive at these feeders during 2 h of experiment. In control tests, in which no forager had been trained, not
a single newcomer alighted at any of the offered carbohydrate food sources. This indicates that, during the foraging process,
a nest-based input provided by successful foragers must have stimulated nestmates to search for food. Once activated, the
newcomers’ choice on where to collect was strongly influenced by field-based social information. The mere visual presence
of accumulated conspecifics (wasp dummies placed on one of the feeders) attracted newcomers to the food sources. Interestingly,
however, visual enhancement was not the only decision-biasing factor at the feeding site. In an experimental series where
searching wasps had to choose between the experimental feeder at which 3 foragers continuously collected and the control feeder
with nine wasp dummies, only 40% of the wasps chose the visually enhanced feeder. This points to the existence of additional
mechanisms of local enhancement. The possibility that, in social wasps, recruitment is involved in the exploitation of carbohydrate
food sources is discussed. 相似文献
482.
M. B. McEachern John M. Eadie Dirk H. Van Vuren 《Behavioral ecology and sociobiology》2007,61(9):1459-1469
We used DNA microsatellites to investigate temporal and spatial patterns of local genetic differentiation and relatedness
in a solitary mammal, the dusky-footed woodrat (Neotoma fuscipes). Patterns of genetic variation were measured relative to spatial clusters, or neighborhoods, of woodrats. We detected significant genetic differentiation among woodrat neighborhoods in two populations spanning multiple
habitat types and densities. Estimates of θ
ST
among neighborhoods ranged 0.034–0.075 and were comparable to levels reported in social mammals. Genetic differentiation
at such a local scale is noteworthy because it occurred in the absence of any physical barriers to gene flow, suggesting that
the patterns observed are linked to the nonrandom patterns of mating and dispersal that characterize woodrat social structure.
Genetic differentiation and relatedness among neighborhoods were even higher when only resident females were analyzed. These
results are consistent with a pattern of female philopatry and male-biased dispersal in woodrats. Geographic distance and
relatedness were inversely correlated in adult females at intermediate densities, but not at low densities. Nonetheless, matrilineal
genetic structure was apparent even at low woodrat densities based on estimates of θ
ST
among neighborhoods of resident females that were significantly greater than zero and consistently greater than estimates
including all individuals. In summary, this study demonstrates a matrilineal genetic structure in dusky-footed woodrats. In
addition, our results support the idea that intermediate densities may be better at facilitating the formation of spatial
kin clusters than either extreme.
An erratum to this article can be found at 相似文献
483.
Ludivine de Menten Denis Fournier Colin Brent Luc Passera Edward L. Vargo Serge Aron 《Behavioral ecology and sociobiology》2005,58(6):527-533
Social Hymenoptera are general models for the study of parent-offspring conflict over sex ratio, because queens and workers frequently have different reproductive optima. The ant Pheidole pallidula shows a split distribution of sex ratios with most of the colonies producing reproductives of a single sex. Sex ratio specialization is tightly associated with the breeding system, with single-queen (monogynous) colonies producing male-biased brood and multiple-queen (polygynous) colonies female-biased brood. Here, we show that this sex specialization is primarily determined by the queens influence over colony sex ratio. Queens from monogynous colonies produce a significantly more male-biased primary sex ratio than queens from polygynous colonies. Moreover, queens from monogynous colonies produce a significantly lower proportion of diploid eggs that develop into queens and this is associated with lower rate of juvenile hormone (JH) production compared to queens from polygynous colonies. These results indicate that queens regulate colony sex ratio in two complementary ways: by determining the proportion of female eggs laid and by hormonally biasing the development of female eggs into either a worker or reproductive form. This is the first time that such a dual system of queen influence over colony sex ratio is identified in an ant. 相似文献
484.
以考察污染者负担原则的起源为基础,从内涵、目的、负担范围和负担转移方式4方面剖析了污染者负担原则在我国的演变过程,从中阐述其在环境保护管理中的重要意义。 相似文献
485.
Genetic diversity might increase the performance of social groups by improving task efficiency or disease resistance, but direct experimental tests of these hypotheses are rare. We manipulated the level of genetic diversity in colonies of the Argentine ant Linepithema humile, and then recorded the short-term task efficiency of these experimental colonies. The efficiency of low and high genetic diversity colonies did not differ significantly for any of the following tasks: exploring a new territory, foraging, moving to a new nest site, or removing corpses. The tests were powerful enough to detect large effects, but may have failed to detect small differences. Indeed, observed effect sizes were generally small, except for the time to create a trail during nest emigration. In addition, genetic diversity had no statistically significant impact on the number of workers, males and females produced by the colony, but these tests had low power. Higher genetic diversity also did not result in lower variance in task efficiency and productivity. In contrast to genetic diversity, colony size was positively correlated with the efficiency at performing most tasks and with colony productivity. Altogether, these results suggest that genetic diversity does not strongly improve short-term task efficiency in L. humile, but that worker number is a key factor determining the success of this invasive species.Communicated by L. Sundström 相似文献
486.
We study interactions between resource distributions, grouping, and diet development in foragers who learn by trial-and-error. We do this by constructing an individual-based model where individuals move and forage in groups in a 2-D space with high resource diversity and learn what to eat. By comparing diet development in different resource distributions, and in gregarious and solitary individuals, we elucidate how these factors affect patterns of diet variation. Our results indicate that different resource distributions have profound effects on learning opportunities, and thereby lead to contrasting phenomena. In uniform environments, local resource depletion by gregarious individuals, in interaction with learning, leads to diet differentiation. In patchy environments, grouping leads to enhanced diet overlap within groups and leads to differences in diet between groups. Surprisingly, mixed environments can generate all these phenomena simultaneously. Our results predict relationships between diet variation, trial-and-error learning, and resource distributions. The phenomena we describe are not evolved strategies, but arise spontaneously when groups of individuals learn to forage in certain resource distributions. This suggests that describing diet specialization or diet homogenization as the result of behavioral strategies may not always be justified. 相似文献
487.
Reproductive skew theory has been an important component of efforts to design a unifying theory of social evolution, as it aims to explain patterns of reproductive partitioning in animal societies as a function of relatedness, group productivity, fighting ability and ecological constraints on independent reproduction. However, empirical tests of the theory have often provided ambiguous or non-conclusive results, assumptions behind alternative models have rarely been tested, and theoretical elaborations have shown the limitations of the reproductive skew approach. Here we analyse a relatively large sample of colonies of the Stenogastrine wasp Parischnogaster mellyi with a powerful set of DNA microsatellite markers. We show that various apparently stable forms of social organisation co-exist in a single population, and that sharing of reproduction between related and unrelated egg-laying females occurs in some of the nests. Present reproductive skew theory appears to be at best partly sufficient to account for the observed complexity of social organisation. The observed patterns of colony composition and reproductive sharing are weakly consistent with the hypothesis of reproductive transactions, while they can more parsimoniously be explained by the life-history characteristics of the species.Communicated by R.F.A. Moritz 相似文献
488.
Sonia Kaushik Bandhana Katoch Vidyanand Nanjundiah 《Behavioral ecology and sociobiology》2006,59(4):521-530
The Dictyostelid or cellular slime moulds (CSMs) are soil amoebae with an asexual life cycle involving social behaviour and
division of labour. The most obvious distinction is between ‘germ line’ or pre-spore cells, which survive, and ‘somatic’ or
pre-stalk cells, which eventually die. A plausible hypothesis to explain the apparent altruism of pre-stalk cells is that
it is directed at clonal relatives. We have tested this hypothesis by comparing indices of altruistic behaviour between clonal
and chimeric (genetically heterogeneous) social groups. The groups were generated by mixing amoebae belonging to distinguishable
strains of Dictyostelium giganteum. The amoebae of one strain do not aggregate at all when mixed with any of three other strains and aggregate poorly with a
fourth. Among the latter, co-aggregation occurs but is followed by varying extents of sorting out. At times, two strains form
separate fruiting bodies; in other cases, they remain together but are clustered in clonal groups within a single chimeric
structure. Our expectation was that the allocation of cells to the stalk pathway would be higher, and to the spore pathway
lower, in clonal social groups than in chimeras. The expectation was not always fulfilled. In addition, three strains could
be arrayed in a linear rank order in terms of the relative efficiencies of spore-formation in binary mixtures; but when all
three were mixed, they were equally efficient. More than overall genetic similarity, cell fate in a chimera seems to result
from complex non-linear interactions based on epigenetic differences. 相似文献
489.
M. M. Webster J. Goldsmith A. J. W. Ward P. J. B. Hart 《Behavioral ecology and sociobiology》2007,62(2):273-280
The structure of social animal groups can be dynamic, characterized by high rates of group fission and fusion. Despite this,
group composition is often well ordered by factors such as species, body size and by numerous other phenotypic traits. Research
in shoaling fishes has revealed that individuals refine group membership decisions still further and are capable of assimilating
chemical cues pertaining to recent habitat and prey use by prospective group mates, preferring to associate with others whose
recent resource use history closely matches their own. In this study, we firstly examined the dynamics of the formation and
breakdown of these preferences, revealing that they can be acquired and replaced in a matter of just a few hours. Using such
cues enables individuals to accurately assess the resource use of conspecifics, allowing them to indirectly sample the local
environment while reducing the chances of acquiring outdated information that can precipitate maladaptive behaviors. Secondly,
we found that shoals composed of individuals with shared recent habitat use history were more cohesive compared to those where
the constituent individuals differed in recent habitat use. Increased shoal cohesion may reduce predation risk, and could
enhance the ability of individuals to detect and use social information. 相似文献
490.
Reintroduction programs for conservation purposes suffer from low post-release survival of captive-bred animals, especially so with fish reintroductions. High mortality is most often due to weakened antipredator skills, which could be enhanced through direct experience with predators and social learning. As yet, the relative efficiency of these learning methods has not been tested, and the significance of the factors determining how efficiently antipredator responses are transmitted socially from experienced (demonstrator) to predator naive (observer) individuals is largely unknown. Using hatchery-bred stock of the endangered Saimaa Arctic charr (Salvelinus alpinus), we show for the first time that: (1) contrary to theoretical predictions, acquired predator recognition was only socially transmitted from predator-experienced to predator-naive fish in groups with a smaller proportion of experienced than naive individuals, and that (2) socially acquired avoidance of the predator odors was as strong as in those fish conditioned with a combination of odors and predator exposure. We conclude that using social transmission procedures in training fish for reintroduction programs may provide considerable ecological, economical and ethical advantages.Communicated by J. Krause 相似文献