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1.
Sean O'Donnell 《Behavioral ecology and sociobiology》1998,43(4-5):327-331
Dominance interactions affected patterns of non-reproductive division of labor (polyethism) in the eusocial wasp Mischocyttarus mastigophorus. Socially dominant individuals foraged for food (nectar and insect prey) at lower rates than subordinate individuals. In
contrast, dominant wasps performed most of the foraging for the wood pulp used in nest construction. Social dominance also
affected partitioning of materials collected by foragers when they returned to the nest. Wood pulp loads were never shared
with nest mates, while food loads, especially insect prey, were often partitioned with other wasps. Dominant individuals on
the nest were more likely to take food from arriving foragers than subordinate individuals. The role of dominance interactions
in regulating polyethism has evolved in the eusocial paper wasps (Polistinae). Both specialization by foragers and task partitioning
have increased from basal genera (independent-founding wasps, including Mischo-cyttarus spp.) to more derived genera (swarm-founding Epiponini). Dominance interactions do not regulate forager specialization or
task partitioning in epiponines. I hypothesize that these changes in polyethism were enabled by the evolution of increased
colony size in the Epiponini.
Received: 8 December 1997 / Accepted after revision: 28 March 1998 相似文献
2.
Michael M. Reddy Kotra V. Krishnamurty Eugene Shpirt G. Anders Carlson Leo Hetling 《Environment international》1982,7(5):315-323
Total and particulate metal concentrations, measured during intensive synoptic studies of the Genesee River, NY, correlated with suspended-sediment concentration and river discharge. Dissolved metal concentrations, on the other hand, showed little systematic variation over the length of the river. Metal and sediment fluxes for two elevated-discharged periods peaked at a midbasin sampling site. For most metals at most sampling sties particulate materials comprised over one-half of the total material. Comparison of particulate material metal concentrations, normalized to the measured suspended-sediment concentrations had with basinwide average values shows that sites having low suspended-sediment concentrations had high particulate material metal contents relative to the basin averages, while sites with high suspended-sediment concentration had low metal contents. These results are consistent with a metal transport mechanism in the Genesee River involving (1) a nearly constant dissolved component, (2) a fine acid-soluble component, and (3) a coarse component that is effectively a neutral diluent in the sediment. Chemical factors, such as sediment organic content, also appear to affect metal transport in the Genesee River. 相似文献
3.
The control of water collection in honey bee colonies 总被引:1,自引:0,他引:1
A honey bee (Apis mellifera) colony adaptively controls the collection of water by its foragers, increasing it when high temperatures necesssitate evaporative cooling inside the hive and decreasing it when the danger of overheating passes. This study analyzes the mechanisms controlling water collection once it has begun, that is, how a colony's water collectors know whether to continue or stop their activity. M. Lindauer suggested that water collectors acquire information about their colony's need for more water by noting how easily they can unload their water to bees inside the hive. In support of this hypothesis, we found that a water collector's ease of unloading does indeed change when her colony's need for water changes. How does a water collector sense the ease of unloading? Multiple variables of the unloading experience change in relation to a colony's water need. Three time-based variables – initial search time, total search time, and delivery time – all change quite strongly. But what changes most strongly is the number of unloading rejections (refusals by receiver bees to take the water), suggesting that this is the primary index of ease of unloading. Why does a water collector's ease of unloading change when her colony's need for water changes? Evidently, what links these two variables is change in the number of water receivers. These are middle-aged bees that receive water just inside the hive entrance, then transport it deeper inside the hive, and finally smear it on the walls of cells or give it to other bees, or both. A colony increases the number of water receivers when its water need increases by having bees engaged in nectar reception and other tasks (and possibly also bees that are not working) switch to the task of water reception. Evidently the activation of additional water receivers does not strongly reduce the number of nectar receivers in a colony, since a colony can increase greatly its water collection without simultaneously decreasing its collection of rich nectar. This study provides a clear example of the way that the members of a social insect colony can use indirect indicators of their colony's labor needs to adaptively control the work that they perform. 相似文献
4.
Kazuki Tsuji 《Behavioral ecology and sociobiology》1994,35(2):109-113
The queenless ant Pristomyrmex pungens has an unusual social structure, in which all workers reproduce parthenogenetically and help others. Laboratory experiments manipulating the proportion of post-reproductive foragers in the colony at various rates suggested that colonies with 5–10% forager ratios had the maximum efficiency per-worker. This result suggests that the cooperative colonies may be maintained by colony-level natural selection. Non-cooperative mutants that oviposit but do not forage should increase in relative frequency in the colony in the short term. However, decreased colony productivity and the resulting competition among colonies might eliminate colonies dominated by such mutants in the long term. P. pungens has a viscous population without migration between colonies, which may facilitate this process. 相似文献
5.
Raphaël Jeanson Jennifer H. Fewell Root Gorelick Susan M. Bertram 《Behavioral ecology and sociobiology》2007,62(2):289-298
Empirical evidence suggests that division of labor in insect societies is positively related to group size both within and
across taxa. Response threshold models (RTM) have been commonly used to analyze patterns of division of labor. However, these
models have been explored empirically and theoretically for only a limited number of tasks, and few studies have examined
predictions of the model as colony size and work availability change. We theoretically examine how group size influences division
of labor using a fixed response-threshold model. We simultaneously explore how expected by-products of increased colony size,
including demand (total work need relative to total work force available) and task number, affect this relationship. Our results
indicate that both low demand and high task number positively influence division of labor. We suggest that these changes parallel
what is observed within social groups as their size increases, and that, in part, the commonly observed increased division
of labor with increasing group size is emergent. 相似文献
6.
In temperate regions, older eusocial hymenopteran females with annual life cycles (annual-temperate) tend to dominate younger females, a behavior demonstrated by many Polistes. However, in queenless ponerine ants and primitively eusocial tropical wasps (perennial/tropical), a younger female can be dominant and occasionally takes over from the older, most dominant reproductive female, the alpha. We investigated these patterns using an inclusive fitness model. The most important difference between the above two cases lay in the length of individual life compared with colony life. Colonies dissolve before winter in the annual-temperate case, so the expected future tenure of the replacement alpha is never longer than that of the original alpha. This makes the non-reproductive subordinate tactic more advantageous for individuals that emerge later in the season because of the fitness cost of superseding. The perennial/tropical case does not have a clear upper limit for colony longevity, so the model predicts that late-born younger daughters are more likely to challenge their mother-alpha because of the expected long future tenure of the new alpha compared with the small indirect cost of the mothers reproductive failure. To switch tactics from being a subordinate to being the new alpha is only optimal in some situations. The high mortality rate of subordinate workers does not qualitatively alter the above pattern. The specific sexual production schedule of the colony sometimes affects the optimal behavior of females in the perennial/tropical case, and older individuals can dominate younger ones when the end of current round of sexual production is imminent.Electronic Supplementary Material Supplementary material is available for this article at 相似文献
7.
Solitary foragers can balance demands for food and safety by varying their relative use of foraging patches and their level of vigilance. Here, we investigate whether colonies of the ant, Formica perpilosa, can balance these demands by dividing labor among workers. We show that foragers collecting nectar in vegetation near their nest are smaller than are those collecting nectar at sites away from the nest. We then use performance tests to show that smaller workers are more likely to succumb to attack from conspecifics but feed on nectar more efficiently than larger workers, suggesting a size-related trade-off between risk susceptibility and harvesting ability. Because foragers that travel away from the nest are probably more likely to encounter ants from neighboring colonies, this trade-off could explain the benefits of dividing foraging labor among workers. In a laboratory experiment, we show that contact with aggressive workers results in an increase in the mean size of recruits to a foraging site: this increase was not the result of more large recruits, but rather because fewer smaller ants traveled to the site. These results suggest that workers particularly susceptible to risk avoid dangerous sites, and suggest that variation in worker size can allow colonies to exploit profitably both hazardous and resource-poor patches.Communicated by L. Sundström 相似文献
8.
The caterpillars of Eucheira socialis westwoodi cooperatively spin and maintain a hollow silken nest and an elaborate network of silken foraging trails on their host plant,
madrone (Arbutus spp.: Ericaceae). Nests typically contain several hundred larvae. Two populations are known to harbor a sex ratio distorter.
The primary sex ratio in these two populations for four generations has been exceedingly male biased (64–79% male). Lepidoptera
larvae are easily sexed using external morphology, allowing us to uniquely mark male and female larvae and to assemble larval
groups of particular sex ratios. We report here the results of experiments on sex-specific larval behavior and physiology
and the effect of colony sex ratio on individual behavior. We found that male larvae spent more time spinning silk on the
nest and less time feeding than female larvae. Males were the first to emerge from the nest and the first to venture out along
trails to feed. Male-biased nests had a significantly greater amount of silk deposited on their surfaces than female-biased
nests. In the field, male-biased nests produced heavier male and female pupae than female-biased nests. Male and female larvae
in 75% male nests became active earlier than males and females in other sex ratio treatments.
Received: 11 September 1998 / Received in revised form: 24 February 1999 / Accepted: 27 March 1999 相似文献
9.
Polymorphism frequently correlates with specialized labor in social insects, but extreme morphologies may compromise behavioral
flexibility and thus limit caste evolution. The ant genus Pheidole has dimorphic worker subcastes in which major workers appear limited due to their morphology to performing defensive or trophic
functions, thus providing an ideal model to investigate specialization and plasticity. We examined worker morphology, brood-care
flexibility, and subcaste ratio in 17 species of tropical twig-nesting Pheidole by quantifying nursing by major workers in natural colonies and in subcolonies lacking minors, in which we also measured
brood survival and growth. Across species, majors performed significantly less brood care than minors in intact colonies,
but increased rates of brood care 20-fold in subcolonies lacking minors. Brood nursed by majors had lower survival than brood
tended by minors, although rates of brood growth did not vary between subcastes. Significant interspecific variation in rates
of brood care by major workers did not lead to significant differences in brood growth or survival. Additionally, we did not
find a significant association between the degree of major worker morphometric specialization and rates of nursing, growth,
or survival of brood among species. Therefore, major workers showed reduced efficacy of brood care, but the degree of morphological
specialization among species did not directly compromise task plasticity. The compact nests and all-or-nothing consequences
of predation or disturbance on colony fitness may have influenced the evolution of major worker brood-care competency in twig-nesting
Pheidole.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Dedicated to Professor Edward O. Wilson on the occasion of his 80th birthday. 相似文献
10.
Elva J. H. Robinson Thomas O. Richardson Ana B. Sendova-Franks Ofer Feinerman Nigel R. Franks 《Behavioral ecology and sociobiology》2009,63(5):779-636
Ant colonies are factories within fortresses (Oster and Wilson 1978). They run on resources foraged from an outside world fraught with danger. On what basis do individual ants decide to leave the safety of the nest? We investigated the relative roles of social information (returning nestmates), individual experience and physiology (lipid stores/corpulence) in predicting which ants leave the nest and when. We monitored Temnothorax albipennis workers individually using passive radio-frequency identification technology, a novel procedure as applied to ants. This method allowed the matching of individual corpulence measurements to activity patterns of large numbers of individuals over several days. Social information and physiology are both good predictors of when an ant leaves the nest. Positive feedback from social information causes bouts of activity at the colony level. When certain social information is removed from the system by preventing ants returning, physiology best predicts which ants leave the nest and when. Individual experience is strongly related to physiology. A small number of lean individuals are responsible for most external trips. An individual’s nutrient status could be a useful cue in division of labour, especially when public information from other ants is unavailable. 相似文献