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1.
Honeybees present a paradox that is unusual among the social Hymenoptera: extremely promiscuous queens generate colonies of nonreproducing workers who cooperate to rear reproductives with whom they share limited kinship. Extreme polyandry, which lowers relatedness but creates within-colony genetic diversity, produces substantial fitness benefits for honeybee queens and their colonies because of increased disease resistance and workforce productivity. However, the way that these increases are generated by individuals in genetically diverse colonies remains a mystery. We assayed the foraging and dancing performances of workers in multiple-patriline and single-patriline colonies to discover how within-colony genetic diversity, conferred to colonies by polyandrous queens, gives rise to a more productive foraging effort. We also determined whether the initiation by foragers of waggle-dance signaling in response to an increasing sucrose stimulus (their dance response thresholds) was linked to patriline membership. Per capita, foragers in multiple-patriline colonies visited a food source more often and advertised it with more waggle-dance signals than foragers from single-patriline colonies, although there was variability among multiple-patriline colonies in the strength of this difference. High-participation patrilines emerged within multiple-patriline colonies, but their more numerous foragers and dancers were neither more active per capita nor lower-threshold dancers than their counterparts from low-participation patrilines. Our results demonstrate that extreme polyandry does not enhance recruitment effort through the introduction of low-dance-threshold, high-activity workers into a colony’s population. Rather, genetic diversity is critical for injecting into a colony’s workforce social facilitators who are more likely to become engaged in foraging-related activities, so boosting the production of dance signals and a colony’s responsiveness to profitable food sources.  相似文献   

2.
In most social insects, worker sterility is reversible, and in the absence of the queen, at least some workers develop ovaries and lay male-destined eggs. In the honeybee, reproductive workers also produce queen-characteristic mandibular and Dufour’s pheromones. The evolution of worker sterility is still under debate as to whether it is caused by queen manipulation (queen-control hypothesis) or represents worker fitness maximization (worker-control hypothesis). In this study, we investigated whether worker fertility and royal pheromone production are reversible under the queen influence. To that effect, we induced ovary activation and queen pheromone production in workers by rearing them as queenless (QL) groups. These workers were subsequently reintroduced into queenright (QR) microcolonies for 1 week, and their ovary status and queen pheromone levels were monitored. Workers reintroduced into QR, but not QL colonies, showed a clear regression in ovary development and levels of the queen pheromones. This is the first demonstration that worker sterility and/or fertility is reversible and is influenced by the queen. These results also emphasize the robustness of the coupling between ovary activation and royal pheromone production, as well as lending credence to the queen-control hypothesis. The dynamics of queen pheromone production in QL workers supports the role of Dufour’s gland pheromone as a fertility signal and that of the mandibular gland pheromone in dominance hierarchies.The two authors, Osnat Malka and Shiri Shnieor, contributed equally to this work.  相似文献   

3.
In most social insect colonies, workers do not attempt to lay eggs in the presence of a queen. However, in the honey bee (Apis mellifera), a rare phenotype occurs in which workers activate their ovaries and lay large numbers of male eggs despite the presence of a fecund queen. We examined the proximate mechanisms by which this ‘anarchistic’ behaviour is expressed. We tested the effects of brood and queen pheromones on retinue attraction and worker ovary activation using caged worker bees. We found no difference between the anarchistic and wild type queen pheromones in the retinue response elicited in either wild type or anarchistic workers. Further, we found that anarchistic queens produce a pheromone blend that is as effective at inhibiting ovary activation as the wild type queen pheromone. However, anarchistic workers are less inhibited by queen pheromones than their wild type counterparts, in a dose-dependent manner. These results show that the anarchistic phenomenon is not due to changes in the production of queen pheromones, but rather is due in part to a shift in the worker response to these queen-produced signals. In addition, we demonstrate the dose-dependent nature of the effect of queen pheromones on honey bee worker ovary activation.  相似文献   

4.
Foraging behavior and the mechanisms that regulate foraging activity are important components of social organization. Here we test the hypothesis that brood pheromone modulates the sucrose response threshold of bees. Recently the honeybee proboscis extension response to sucrose has been identified as a ”window” into a bee’s perception of sugar. The sucrose response threshold measured in the first week of adult life, prior to foraging age, predicts forage choice. Bees with low response thresholds are more likely to be pollen foragers and bees with high response thresholds are more likely to forage for nectar. There is an associated genetic component to sucrose response thresholds and forage choice such that bees selected to hoard high quantities of pollen have low response thresholds and bees selected to hoard low quantities of pollen have higher response thresholds. The number of larvae in colonies affects the number of bees foraging for pollen. Hexane-extractable compounds from the surface of larvae (brood pheromone) significantly increase the number of pollen foragers. We tested the hypothesis that brood pheromone decreases the sucrose response threshold of bees, to suggest a pheromone- modulated sensory-physiological mechanism for regulating foraging division of labor. Brood pheromone significantly decreased response thresholds as measured in the proboscis extension response assay, a response associated with pollen foraging. A synthetic blend of honeybee brood pheromone stimulated and released pollen foraging in foraging bioassays. Synthetic brood pheromone had dose-dependent effects on the modulation of sucrose response thresholds. We discuss how brood pheromone may act as a releaser of pollen foraging in older bees and a primer pheromone on the development of response thresholds and foraging ontogeny of young bees. Received: 24 May 2000 / Revised: 26 September 2000 / Accepted: 15 October 2000  相似文献   

5.
Foragers of many ant species use pheromone trails to guide nestmates to food sources. During foraging, individual workers can also learn the route to a food source. Foragers of the mass-recruiting ant Lasius niger use both pheromone trails and memory to locate a food source. As a result, an experienced forager can have a conflict between social information (trail pheromones) and private information (route memory) at trail bifurcations. We tested decision making in L. niger foragers facing such an informational conflict in situations where both the strength of the pheromone trail and the number of previous visits to the food source varied. Foragers quickly learned the branch at a T bifurcation that leads to a food source, with 74.6% choosing correctly after one previous visit and 95.3% after three visits. Pheromone trails had a weaker effect on choice behaviour of naïve ants, with only 61.6% and 70.2% choosing the branch that had been marked by one or 20 foragers versus an unmarked branch. When there was a conflict between private and social information, memory overrides pheromone after just one previous visit to a food source. Most ants, 82–100%, chose the branch where they had collected food during previous foraging trips, with the proportion depending on the number of previous trips (1 v. 3) but not on the strength of the pheromone trail (1 v. 20). In addition, the presence of a pheromone trail at one branch in a bifurcation had no effect on the time it took an experienced ant to choose the correct branch (the branch without pheromone). These results suggest that private information (navigational memory) dominates over social information (chemical tail) in orientation decisions during foraging activities in experienced L. niger foragers.  相似文献   

6.
This study investigates the brief piping signals ("stop signals") of honey bee workers by exploring the context in which worker piping occurs and the identity and behavior of piping workers. Piping was stimulated reliably by promoting a colony's nectar foraging activity, demonstrating a causal connection between worker piping and nectar foraging. Comparison of the behavior of piping versus non-piping nectar foragers revealed many differences, e.g., piping nectar foragers spent more time in the hive, started to dance earlier, spent more time dancing, and spent less time on the dance floor. Most piping signals (approximately 99%) were produced by tremble dancers, yet not all (approximately 48%) tremble dancers piped, suggesting that the short piping signal and the tremble dance have related, but not identical, functions in the nectar foraging communication system. Our observations of the location and behavior of piping tremble dancers suggest that the brief piping signal may (1) retard recruitment to a low-quality food source, and (2) help to enhance the recruitment success of the tremble dance.  相似文献   

7.
Foraging and the mechanisms that regulate the quantity of food collected are important evolutionary and ecological attributes for all organisms. The decision to collect pollen by honey bee foragers depends on the number of larvae (brood), amount of stored pollen in the colony, as well as forager genotype and available resources in the environment. Here we describe how brood pheromone (whole hexane extracts of larvae) influenced honey bee pollen foraging and test the predictions of two foraging-regulation hypotheses: the indirect or brood-food mechanism and the direct mechanism of pollen-foraging regulation. Hexane extracts of larvae containing brood pheromone stimulated pollen foraging. Colonies were provided with extracts of 1000 larvae (brood pheromone), 1000 larvae (brood), or no brood or pheromone. Colonies with brood pheromone and brood had similar numbers of pollen foragers, while those colonies without brood or pheromone had significantly fewer pollen foragers. The number of pollen foragers increased more than 2.5-fold when colonies were provided with extracts of 2000 larvae as a supplement to the 1000 larvae they already had. Within 1 h of presenting colonies with brood pheromone, pollen foragers responded to the stimulus. The results from this study demonstrate some important aspects of pollen foraging in honey bee colonies: (1) pollen foragers appear to be directly affected by brood pheromone, (2) pollen foraging can be stimulated with brood pheromone in colonies provided with pollen but no larvae, and (3) pollen forager numbers increase with brood pheromone as a supplement to brood without increasing the number of larvae in the colony. These results support the direct-stimulus hypothesis for pollen foraging and do not support the indirect-inhibitor, brood-food hypothesis for pollen-foraging regulation. Received: 5 March 1998 / Accepted after revision: 29 August 1998  相似文献   

8.
In this paper, we used the food-correlated search behavior observed in foraging ants returning to a previously rewarding site to study information transfer during recruitment in the ant Lasius niger. We hypothesized that, if information about the characteristics of the food is conveyed during recruitment, food-correlated search tactics should also be observed in recruited workers. Our results show that the characteristics of the trajectories of recruited workers are comparable to those of scout ants returning to a site or prior food find and depend more on the type (prey/sugar) than on the quality (sugar concentration) of the food discovered by the scouts. Independent of sugar concentration, workers recruited to a source of sugar search with a greater sinuosity than workers recruited to a prey. Experimental manipulation of the recruitment signals (chemical trail and contact between ants) shows that the trail pheromone laid down by recruiting ants does not play a role in the modification of trajectory sinuosity. This change appears to be most likely triggered by a direct perception of the residue of sugar smeared on the body of the recruiting workers coming back to the nest.Communicated by J. Heinze  相似文献   

9.
Recent studies indicate that the foraging success of a honeybee colony is enhanced when it has numerous genetically diverse patrilines because of queen polyandry. We determined whether foraging is improved in part because patriline diversity generates more responsive populations of scouting foragers. Scouts search for new food sources and advertise them with waggle dances to inform other foragers about unexploited discoveries. We moved multiple-patriline and single-patriline colonies to unfamiliar locations so that colonies relied heavily on successful scouts to initiate recruitment and then compared the development of foraging effort between the two types of colonies. More waggle dance signals were produced during the incipient stages of foraging in multiple-patriline colonies compared to single-patriline colonies because scouts reported food discoveries with longer dances. Scouts also returned to multiple-patriline colonies at rates that were two thirds higher than those of single-patriline colonies, although return rates for general forager populations were not significantly different between colony types. The distance of reported food sources from hives increased with time for all colonies, but by the end of their first day in an unfamiliar environment, maximal foraging reach was greater if colonies had multiple patrilines. Most scouts in multiple-patriline colonies came from a minority of scout-rich patrilines that were generally not those from which general forager populations were derived; the presence of such scout-rich patrilines was correlated with the extent of recruitment signaling in colonies. We show how a honeybee colony’s scouting effort is (and is not) enhanced when extremely polyandrous queens produce genetically diverse colonies.  相似文献   

10.
In the annual bumblebee Bombus terrestris, the onset of queen-worker conflict over male production is seasonally and socially constrained. Workers will do better if they start to reproduce (the so-called competition phase) only after ascertaining that larvae are committed to gyne development but before the season ends because they gain more by rearing sister-gynes than their own sons. Here, we tested two nonmutually exclusive hypotheses as to what triggers the onset of worker reproduction: Workers can directly monitor larval development and/or workers eavesdrop on the queen signal that directs gyne development. Exposing workers to gyne larvae through a double mesh did not advance the competition phase compared to control colonies. However, when workers, but not the queen, were allowed contact with gyne larvae, both the competition phase and gyne production were advanced. Thus, while larvae do not emit a volatile pheromone that discloses their developmental route, the physical contact of workers with such larvae triggers early competition phase. However, workers exclusively exposed to worker larvae (colonies prevented from producing gyne larvae) started to reproduce at the same time as control colonies. Replacing the resident queen with an older queen (from gyne-rearing colonies) advanced the competition phase, irrespective of worker age. The results are consistent with the hypothesis that workers eavesdrop on the queen pheromones. This is adaptive because it allows workers a broader time-window for reproduction and thus to gain fitness from rearing both sister-gynes and sons before the season ends without affecting colony development.  相似文献   

11.
In social insects, the decision to exploit a food source is made both at the individual (e.g., a worker collecting a food item) and colony level (e.g., several workers communicating the existence of a food patch). In group recruitment, the recruiter lays a temporary chemical trail while returning from the food source to the nest and returns to the food guiding a small group of nestmates. We studied how food characteristics influence the decision-making process of workers changing from individual retrieving to group recruitment in the gypsy ant Aphaenogaster senilis. We offered field colonies three types of prey: crickets (cooperatively transportable), shrimps (non-transportable), and different quantities of sesame seeds (individually transportable). Colonies used group recruitment to collect crickets and shrimps, as well as seeds when they were available in large piles, while small seed piles rarely led to recruitment. Foragers were able to “measure” food characteristics (quality, quantity, transportability), deciding whether or not to recruit, accordingly. Social integration of individual information about food emerged as a colony decision to initiate or to continue recruitment when the food patch was rich. In addition, group recruitment allowed a fast colony response over a wide thermal range (up to 45°C ground temperature). Therefore, by combining both advantages of social foraging (group recruitment) and thermal tolerance, A. senilis accurately exploited different types of food sources which procured an advantage against mass-recruiting and behaviorally dominant species such as Tapinoma nigerrimum and Lasius niger.  相似文献   

12.
Many ant species are polydomous, forming multiple spatially segregated nests that exchange workers and brood. However, why polydomy occurs is still uncertain. We investigated whether colonies of Crematogaster torosa form new polydomous nests to better exploit temporally stable food resources. Specifically, we tested the effect of food presence or absence and distance on the likelihood that colonies would form a new nest. Because this species also forms little-known structures that house only workers without brood (outstations), we also compared the function of this structure with true nests. Laboratory-reared colonies were connected to a new foraging arena containing potential nest sites with or without food for 4 months. When food was present, most colonies formed polydomous nests nearby and the remainder formed outstations. When food was absent, the behavior of colonies differed significantly, frequently forming outstations but never polydomous nests. Distance had no effect on the type of structure formed, but when food was present, a larger proportion of the workforce moved shorter distances. Workers often fortified the entrances to both structures and used them for storage of dried insect tissue (“jerky”). In an investigation of spatial fidelity, we found that workers on the between-nest trail were associated with the original nest, whereas workers collecting food were more likely to be associated with the new nest or outstation. C. torosa appears to have a flexible colony structure, forming both outstations and polydomous nests. Polydomous nests in this species were associated with foraging and were only formed near food resources.  相似文献   

13.
Multiple mating by honeybee queens results in colonies of genotypically diverse workers. Recent studies have demonstrated that increased genetic diversity within a honeybee colony increases the variation in the frequency of tasks performed by workers. We show that genotypically diverse colonies, each composed of 20 subfamilies, collect more pollen than do genotypically similar colonies, each composed of a single subfamily. However, genotypically similar colonies collect greater varieties of pollen than do genotypically diverse colonies. Further, the composition of collected pollen types is less similar among genotypically similar colonies than among genotypically diverse colonies. The response threshold model predicts that genotypic subsets of workers vary in their response to task stimuli. Consistent with this model, our findings suggest that genotypically diverse colonies likely send out fewer numbers of foragers that independently search for pollen sources (scouts) in response to protein demand by the colony, resulting in a lower variety of collected pollen types. The cooperative foraging strategy of honeybees involves a limited number of scouts monitoring the environment that then guide the majority of foragers to high quality food sources. The genetic composition of the colony appears to play an important role in the efficiency of this behavior.  相似文献   

14.
Foragers can improve search efficiency, and ultimately fitness, by using social information: cues and signals produced by other animals that indicate food location or quality. Social information use has been well studied in predator–prey systems, but its functioning within a trophic level remains poorly understood. Eavesdropping, use of signals by unintended recipients, is of particular interest because eavesdroppers may exert selective pressure on signaling systems. We provide the most complete study to date of eavesdropping between two competing social insect species by determining the glandular source and composition of a recruitment pheromone, and by examining reciprocal heterospecific responses to this signal. We tested eavesdropping between Trigona hyalinata and Trigona spinipes, two stingless bee species that compete for floral resources, exhibit a clear dominance hierarchy and recruit nestmates to high-quality food sources via pheromone trails. Gas chromatography–mass spectrometry of T. hyalinata recruitment pheromone revealed six carboxylic esters, the most common of which is octyl octanoate, the major component of T. spinipes recruitment pheromone. We demonstrate heterospecific detection of recruitment pheromones, which can influence heterospecific and conspecific scout orientation. Unexpectedly, the dominant T. hyalinata avoided T. spinipes pheromone in preference tests, while the subordinate T. spinipes showed neither attraction to nor avoidance of T. hyalinata pheromone. We suggest that stingless bees may seek to avoid conflict through their eavesdropping behavior, incorporating expected costs associated with a choice into the decision-making process.  相似文献   

15.
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   

16.
1.  Scouts of the harvester ant Pogonomyrmex barbatus, P. maricopa and P. rugosus which discovered a new rich foraging area recruit nestmates by laying a trail with poison gland contents from the feeding site to the nest. Laboratory experiments have shown that Pogonomyrmex workers are stimulated to follow the trail by the trail pheromone alone.
2.  The biological significance of the recruitment behavior was analyzed in the mesquite-acacia desert in Arizona-New Mexico, where the three species occur sympatrically. P. maricopa recruits less efficiently to food sources than does P. barbatus and P. rugosus. Generally the recruitment activity depends on a number of parameters of the food source, such as distance to the nest, density of the seed fall and size of the grains.
3.  The recruitment activity is also affected by the presence, absence or distance of hostile neighboring colonies.
4.  The use of chemically and visually marked trunk trails which originate from recruitment trails, guarantees and efficient partitioning of foraging grounds. It could be demonstrated that trunk trails, used by P. barbatus and P. rugosus during foraging and homing, have the effect of avoiding aggressive confrontations between neighboring colonies of the same species. They channel the mass of foragers of hostile neighboring nests into diverging directions, before each ant pursues its individual foraging exploration. This channeling subtly partitions the foraging grounds and allows a much denser nest spacing pattern than a foraging strategy without trunk trails, such as that employed by P. maricopa.
5.  The behavioral mechanisms which maintain overdispersion both within and between species of Pogonomyrmex were investigated. Aggressive confrontations at the colony level and aggressive expulsion of foundress queens from the nest territories of mature colonies play thereby a major role. Observational as well as experimental data led to the conclusion that the farther away from its nest the intruder is, the less vigorous are the aggressive confrontations with the defenders. Only when neighboring colonies are located too close together will increased aggressive interactions eventually lead to the emigration of the weaker colony.
6.  P. barbatus and P. rugosus have a wide niche overlap, whereas P. maricopa seems to be more specialized in regard to food. This is consistent with the findings that interspecific territoriality between P. barbatus and P. rugosus is considerably more developed than between these species on the one side and P. maricopa on the other.
7.  Although foundress queens, which venture into a territory of a conspecific mature colony are fiercely attacked, most of them are not injured, but rather dragged or carried to the territorial border and then released.
8.  Nevertheless foraging areas, even of conspecific colonies, frequently overlap, but aggressive interactions there are usually less intense than at the core areas (trunk trails plus nest yards), which normally do not overlap and are vigorously defended.
  相似文献   

17.
Summary Recent studies have shown that differences in patterns of task specialization among nestmate honeybee workers (Apis mellifera) can be explained, in part, as a consequence of genotypic variability. Here, we present evidence supporting the hypothesis that an individual's pattern of task specialization is affected not only by her own genotype, but, indirectly, by the genotypes of her nestmates. Workers from two strains of honey bees, one selected for high pollen hoarding, the other for low pollen hoarding, were observed in colonies of their respective parent strains and in colonies of the other strain. Worker genotype and host-colony type affected foraging activity. Workers from the high strain fostered in low-strain colonies returned with pollen on 75.6% of total foraging trips, while workers from the high strain fostered in high-strain colonies returned with pollen on 53.5% of total trips. Workers from the low strain fostered in low-strain colonies returned with pollen on 34.8% of total foraging trips while workers from the low strain fostered in high-strain colonies returned with pollen on 2.6% of total trips. Similar results were obtained in a second experiment. We suggest that workers influence the behavior of their nestmates indirectly through their effects on the shared colony environment. The asymmetry seen in the response of workers from these strains to the two types of colony environments also suggests that these genotypes exhibit different norms of reaction. Offprint requests to: N.W. Calderone  相似文献   

18.
Julian GE  Cahan SH 《Ecology》2006,87(9):2207-2214
The discovery of genetic caste determination (GCD) in populations of Pogonomyrmex harvester ants raises many questions about the evolution and persistence of such populations. The genetic caste determination arises from the existence of two distinct, but mutually dependent, genetic lineages within a population. Workers always develop from a combination of the two lineages, but their sister queens develop from within-lineage matings. Maintaining genetic caste determination appears to be costly because many queen-destined eggs are wasted when a colony is not in the reproductive stage, yet these populations appear to be widespread. We investigated whether inter-lineage workers have novel traits that give GCD colonies a selective advantage in certain environments. In particular, we compared ecologically relevant behavioral characteristics of inter-lineage workers in H-lineage colonies with co-occurring normal colonies of P. rugosus. First, we measured colony defensive response toward a simulated vertebrate predator. Second, we set up direct competitive foraging and recruitment experiments between dependent lineage and P. rugosus colonies. Last, we measured individual aggressive response to foreign inter-lineage and P. rugosus workers. We found that H1/H2 inter-lineage workers explored objects on the nest more thoroughly and responded much more aggressively to simulated predator disturbance than the P. rugosus colonies. In individual encounters, H1/H2 inter-lineage and P. rugosus workers were equally aggressive toward foreign ants, but both worker types could discriminate P. rugosus from inter-lineage intruders and were more aggressive toward ants of the alternate type to themselves. When competing directly for resources, however, P. rugosus colonies consistently dominated seed piles. In summary, H1/H2 GCD colonies show distinct behavioral differences, but there is no clear ecological advantage from the traits we examined.  相似文献   

19.
Summary Nest construction, a complex social activity requiring the coordination of 3 tasks (Fig.2), was compared in large (<350 adults) and small (<50 adults) colonies of Polybia occidentalis. The 3 tasks—water foraging, pulp foraging, and building—are performed by 3 separate groups of workers (Fig.4). Of the 8 acts comprising the 3 tasks, 5 regularly involve the transfer of water or pulp from one worker to another on the nest.Small colonies required nearly twice as long (35.4 worker-min) as large colonies (20.1 workermin) to complete a unit amount of construction work. Behavioral acts involving material transfer among workers were responsible for most of the increase in small colonies. In other words, the waiting times experienced by material donors and recipients were greater in small colonies. In small colonies workers switched among the three tasks more frequently than in large colonies (Fig. 4). This was the result of more frequent switching by generalists (workers that performed 2 or 3 of the tasks), rather than by a decrease in the proportion of specialists (workers performing only 1 task type) (Fig. 3).The series-parallel system by which Polybia occidentalis organizes nest construction has a major advantage over the series operation of solitary wasps. Pulp foragers collect and carry loads that are 6.1 times as large as builders can work with at the nest, and water foragers bring in loads that appear to be limited only by crop capacity and that provide all the moisture necessary for the complete processing of 0.74 of a foraged pulp load. As a result P. occidentalis can collect and process a given amount of nest material using 2.6 times fewer foraging trips than would be required by the series system. This in turn means that P. occidentalis not only achieves an energy saving that probably more than offsets the increased costs of material handling at the nest, but it reduces the exposure of its foragers to predators in the field.  相似文献   

20.
Summary Foundresses in pre-emergence and post-emergence nests of Belonogaster petiolata were organized into linear dominance hierarchies according to their level of physical aggression towards cofoundresses. The female at the top of the hierarchy became the queen, while foundresses ranked below her became worker-like subordinates. In pre-matrifilial colonies, worker offspring were socially subordinate to both their queen and the subordinate foundresses. Queens of matrifilial colonies retained full social dominance over their workers. Queens were reproductively dominant over subordinates and workers, and laid the majority of, if not all, surviving eggs. Subordinate-laid eggs were invariably discovered and destroyed by the queen through oophagy; workers in pre-matrifilial and matrifilial colonies never laid or ate eggs. Colonies contained a single (and the same) functional queen throughout the pre- and post-emergence periods and were, therefore, long-term monogynous.In both established pre-emergence colonies and post-emergence colonies, virtually all foraging for food and nesting material was performed by the subordinates and workers. More dominant subordinates generally foraged less than low-ranked subordinates. Queens were more active builders than subordinates or workers in pre-matrifilial and matrifilial colonies. Queens enjoyed a surplus in exchanged food loads, while subordinates and workers did not. Among cofoundresses, an advantage in food exchange was also positively associated with dominance rank. Queens solicited larvae for their salivary fluid more often than did subordinates and workers. Among cofoundresses, frequency of adult-larva trophallaxis was positively associated with rank. Queens rested most often in the central zones of the nest containing late instar larvae and pupae, while subordinates and particularly workers spent more time in the peripheral, broodless regions of the nest.This paper is dedicated to the late Professor Leo Pardi, whose pioneering studies of Belonogaster served as a constant source of inspiration and reference for the present work  相似文献   

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