Division Of Labor In Colonies Research Articles

Modeling and simulation of extended ant colony labor division for benefit distribution of the all-for-one tourism supply chain with front and back decoupling.

This paper takes the supply chain alliance under the decoupling of the front and back of the all-for-one tourism as the research object. Considering the three behavior stimuli of self-benefit, altruism, and invariance, this article resets the attributes such as environmental stimuli and response threshold of ants based on the characteristics of the all-for-one tourism supply chain with shared services as the core under the decoupling of the front and back. Moreover, it introduces dual intervention factors to coordinate the benefit distribution process of different member companies, takes fairness as the main goal of benefit distribution, introduces relative deprivation as the measure index of fairness, and establishes a dynamic all-for-one tourism supply chain alliance benefit distribution model. The experimental results show that the extended model has good flexibility of benefit distribution and realizes the fair distribution of supply chain benefits.

Profit Allocation Problem and Algorithm of Network Freight Platform under Carbon Trading Background.

With the gradual popularization of carbon trading, individual carbon emission behavior will come with carbon costs, which will have a significant impact on the network freight platform carrier drivers. Therefore, in order to improve the stability within the network freight platform, this paper considers the fairness of benefit distribution among network freight carriers and aims to offset the impact of carbon cost to a greater extent by reducing the relative deprivation of the network freight platform carrier group, so as to finally realize the benign operation of network freight. This paper introduces a number of indicators such as contribution value, expectation realization degree, and relative deprivation feeling, and establishes a dynamic benefit distribution optimization model oriented by relative deprivation feeling. Based on the basic characteristics of the problem, the ant colony labor division model is extended, and the corresponding algorithm is designed to solve the problem. By introducing the contribution value, contribution rate and expected return to reset the stimulus value of the environment and the response threshold of agent, the relative deprivation sense is used to quantify the degree of unfair benefit distribution, which is used as a benchmark to dynamically coordinate the benefit distribution of the carrier group and optimize the benefit distribution scheme. The experimental results show that the extended model and algorithm designed in this paper can significantly reduce the relative deprivation perception of the carrier group in the online freight platform at a low cost.

The Order Allocation Problem and the Algorithm of Network Freight Platform under the Constraint of Carbon Tax Policy.

In order to solve the problems of improper order allocation and the lack of a carbon emission constraint system in the road freight transportation industry, this paper proposed an order allocation mechanism of network freight transportation with carbon tax constraints and established an order allocation optimization model with carbon tax constraints. Based on the basic characteristics of the problem, this paper redesigns the ant colony labor division expansion model, and designs a corresponding algorithm to solve the problem. By improving the update rules of the stimulus value and the threshold value, the matching difference between the order and the driver of the network freight platform is enlarged, and the matching relation-ship is dynamically adjusted, the order allocation scheme is optimized, and a more appropriate carbon tax rate range in this industry is explored. Furthermore, the problem is solved by a 0-1 integer programming algorithm, which is compared with the algorithm designed in this paper. Through multiple numerical simulation experiments, the effectiveness and feasibility of the algorithm are verified. The experimental results show that the order allocation arrangement of the online freight platform with carbon tax constraints is more economical and environmentally friendly.

Imperial Refugee Management. Moving Greek Refugees Through the British Empire and into the Belgian Congo (1942–1945)

ABSTRACT During the Second World War, 2,700 Greek refugees lived in camps in Eastern Belgian Congo and Ruanda-Urundi. They had escaped from the German Nazi occupation and famine conditions on the Aegean Islands. Their movement through Turkey, Syria, Palestine, Egypt, Kenya, Tanganyika and Uganda was part of a more extensive network of refugee hosting and transfer, orchestrated by British officials in Cairo and guided by strategic interests in London. This article uncovers this overlooked episode and situates it in the broader history of the thousands of European refugees who found refuge in the Middle East and Africa. It argues that this was part of a more extensive system of imperial refugee management with implications for the history of the British Empire and the international refugee regime. Adding to the historiography of the empire’s war effort, it uncovers the contribution of Africans to hosting distressed European refugees. It further highlights the importance of imperial rule in the emergence of the post-war international refugee regime. Due to the racism of the colonial division of labour and society, European refugees in Africa enjoyed a comparably comfortable situation. The imperial refugee regime cared well for its white subjects, housing them in some of the most privileged refugee camps of the world.

Validation of Potential Reference Genes for Real-Time qPCR Analysis in Pharaoh Ant, Monomorium pharaonis (Hymenoptera: Formicidae).

Ants are highly diverse social insects living in colonies consisted of up to millions of individuals with reproductive division of labors. Due to the interests in disclosing the genetic and epigenetic regulation mechanisms underlying the distinct developmental trajectories between castes and division of labor in colonies, many ant species have recently been established as laboratory models for evolutionary development and social behavior studies. These functional studies often request a precise quantification of the relative gene expression level, which relies on a stably expressed reference genes for normalization. A core set of reliable reference genes for this purpose however has not been established yet in ants. In the present study, we tested the expression patterns and amplification efficiencies of 12 abundantly expressed candidate genes in Monomorium pharaonis, one of the few ant species that are suitable for laboratory rearing and experimentation. We quantified the expression levels of these genes by RT-qPCR in seven different conditions: embryo development, sexual development, worker development, adult phenotypes, tissues, and two abiotic manipulative treatments in pharaoh ant. Finally, five genes, elongation factor-1 alpha (EF1A), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), TATA-box-binding protein (TATA), tubulin gamma-2 chain-like (TBLg2), heat shock protein 67B2-like (HSP67) were found to be the most stable reference genes across seven conditions. We also identified the most stable reference genes applicable for each distinct condition and the optimal number of reference genes entailed were evaluated. Our study validates reliable reference genes for RT-qPCR analysis which lays the foundation for future studies in pharaoh ant.

Development of Task Allocation Method for Swarm Robotic Systems Using Optimal Foraging Theory and Ant Colony Labor Division Model

Development of Task Allocation Method for Swarm Robotic Systems Using Optimal Foraging Theory and Ant Colony Labor Division Model

Activity Patterns and Age-dependent Changes in Behavior in the Clonal Ant Platythyrea punctata

Age-based polyethism, wherein young individuals perform tasks within the nest and later transition to outside activities, is common among many social insects. This division of labor ensures the safety of workers with longer residual lifespans, such as brood caring nurses, and exposes only old individuals to increased extrinsic mortality risks. It appears however, that lifespan in workers is also shaped by intrinsic factors, such as senescence. The transition from nurse to forager is accompanied by various physiological and behavioral changes and seems to represent a crucial step in determining the subsequent life history of the individual. Here we investigate the daily activity pattern and detailed division of labor in colonies of the clonal ant Platythyrea punctata to better understand the dynamics of age polyethism in this peculiar species. We found that P. punctata colonies were mostly active during the day. At night, few workers were observed out of their nests. Workers showed a decrease in brood care and aggressive behavior over time. With increasing age individuals spent more time outside the nest and were more frequently observed walking. However, the transition to outside tasks did not follow a consistent time pattern in all colonies. Workers transitioning at a younger age seemed to die earlier than workers that began to forage later in life.

Chemosensory reception in the stingless bee Tetragonisca angustula

In stingless bees, unlike honey bees, the relationship between chemosensory abilities and colony labor division has been poorly studied. Here we examined odor reception and gustatory responsiveness of the stingless bee Tetragonisca angustula focusing on workers, whose are involved in different tasks. Using the proboscis extension response, we studied sucrose response thresholds (SRTs) of foragers and guards. Peripheral responses to odors at the antennae were recorded by electroantennography (EAG). Additionally, we quantified and described the number and type of sensilla present on the antennae using scanning electron microscopy. Foragers’ SRTs changed according to the resource collected: nonpollen foragers showed higher SRTs than pollen foragers and guards, that showed similar sucrose responsiveness. EAG signal strength of both foragers and guards increased with increasing odor concentration. Interestingly, guard bees showed the highest response to citral, an odor that triggers defensive behavior in T. angustula. Type and number of sensilla present in the antennae of guards and foragers were similar. Our results suggest that differences found in chemosensory responses among worker subcastes are task dependent.

Lipid content influences division of labour in a clonal ant.

The fat body, a major metabolic hub in insects, is involved in many functions, e.g. energy storage, nutrient sensing and immune response. In social insects, fat appears to play an additional role in division of labour between egg layers and workers, which specialize in non-reproductive tasks inside and outside their nest. For instance, reproductives are more resistant to starvation, and changes in fat content have been associated with the transition from inside to outside work or reproductive activities. However, most studies have been correlative and we still need to unravel the causal interrelationships between fat content and division of both reproductive and non-reproductive labour. Clonal ants, e.g. Platythyrea punctata, are ideal models for studying task partitioning without confounding variation in genotype and morphology. In this study, we examined the range of variation and flexibility of fat content throughout the lifespan of workers, the threshold of corpulence associated with foraging or reproduction and whether low fat content is a cause rather than a consequence of the transition to foraging. We found that lipid stores change with division of labour from corpulent to lean and, in reverted nurses, back to corpulent. In addition, our data show the presence of fat content thresholds that trigger the onset of foraging or egg-laying behaviour. Our study supports the view that mechanisms that regulate reproduction and foraging in solitary insects, in particular the nutritional status of individuals, have been co-opted to regulate division of labour in colonies of social insects.

Construction of extended ant colony labor division model for traffic signal timing and its application in mixed traffic flow model of single intersection

SummaryThe ant colony labor division model can be used to solve the dynamic and variable traffic signal timing problem because of its adaptive and self‐adjusting characteristics. Based on the basic model, this paper proposes a new extended ant colony labor division model for traffic signal timing. This model is combined with the vehicle characteristics to modify the calculation method of environmental stimulus values. Using the vehicle delay in the unit period, the original fixed response threshold is modified to the dynamic response threshold, and the state transition equation is reconstructed. Based on the mixed traffic flow model of two‐phase single‐point intersection cellular automata, through comparative experiments and discussion and analysis, it is found that the extended ant colony labor division model can effectively improve road traffic capacity according to road conditions and reasonable traffic signal timing.

An Automated Cell Tracking Approach With Multi-Bernoulli Filtering and Ant Colony Labor Division.

In this article, we take as inspiration the labor division into scouts and workers in an ant colony and propose a novel approach for automated cell tracking in the framework of multi-Bernoulli random finite sets. To approximate the Bernoulli parameter sets, we first define an existence probability of an ant colony as well as its discrete density distribution. During foraging, the behavior of scouts is modeled as a chaotic movement to produce a set of potential candidates. Afterwards, a group of workers, i.e., a worker ant colony, is recruited for each candidate, which then embark on gathering heuristic information in a self-organized way. Finally, the pheromone field is formed by the corresponding worker ant colony, from which the Bernoulli parameter is derived and the state of the cell is estimated accordingly to be associated with the existing tracks. Performance comparisons with other previous approaches are conducted on both simulated and real cell image sequences and show the superiority of this algorithm.

MODELING AND SIMULATION OF ANT COLONY'S LABOR DIVISION WITH CONSTRAINTS FOR TASK ALLOCATION OF RESILIENT SUPPLY CHAINS

Emergency incidents increase the uncertainty of supply chain environment, and also make the supply chain vulnerability expose. Creating resilient supply chain is an effective way to overcome the supply chain vulnerability. The supply chain characteristics of self-adaptation and self-coordination are consistent with the self-organization feature of ant colony's labor division. In this paper, a generalized ant colony's labor division model with constraints is provided, which is used to construct the ant colony's labor division model with constraints of resilient supply chain to solve task allocation of resilient supply chains. The simulation principle and algorithm of resilient supply chain are provided based on the proposed model and task allocation of the supply chain is analyzed from the five aspects, that is, task allocation status, supply chain coordination, emergency incidents' impact to task allocation, task allocation rate and the influence of different incidents for task allocation. The simulation results show that, with the proposed model, it is effective to allocate resilient supply chain tasks and has excellent performance, such as faster response and robustness.

Division of labor in colonies of the eusocial wasp, Mischocyttarus consimilis.

The division of labor between castes and the division of labor in workers according to age (temporal polyethism) in social wasps are crucial for maintaining social organization. This study evaluated the division of labor between castes, and the temporal polyethism in workers of Mischocyttarus consimilis Zikán (Hymenoptera: Vespidae). To describe the behavioral repertory of this species, observations were made of 21 colonies, with 100 hours of observations. In order to observe temporal polyethism, each newly emerged wasp was marked with colored dots on the upper area of the thorax. This allowed the observation of behavioral acts performed by each worker from the time of emergence to its death. Through hybrid multidimensional scaling, a clear division between queens and workers could be identified, in which the behaviors of physical dominance and food solicitation characterized the queen caste; while behaviors such as adult—adult trophallaxis, destruction of cells, alarm, foraging for prey, foraging for nectar, and unsuccessful foraging characterized the worker caste. Hybrid multidimensional scaling characterized two groups, with intra—nest activities preferentially accomplished by younger workers, while extra—nest activities such as foraging were executed more frequently by older workers.

Modeling of Ant Colony's Labor Division for the Multi-Project Scheduling Problem and Its Solution by PSO

Modeling of Ant Colony's Labor Division for the Multi-Project Scheduling Problem and Its Solution by PSO

The effect of group size on the interplay between dominance and reproduction in Bombus terrestris.

Social insects provide good model systems for testing trade-offs in decision-making because of their marked reproductive skew and the dilemma workers face when to reproduce. Attaining reproductive skew requires energy investment in aggression or fertility signaling, creating a trade-off between reproduction and dominance. This may be density-dependent because the cost of achieving dominance may be higher in larger groups. We investigated the effect of group-size in B. terrestris queenless workers on two major reproduction-dominance correlates: between-worker aggression, and pheromone production, aiming at mimicking decision-making during the transition of worker behavior from cooperation and sterility to aggressive reproductive competition in whole colonies. Despite the competition, reproductive division of labor in colonies can be maintained even during this phase through the production of a sterility signal by sterile workers that has an appeasement effect on dominant nestmates. Worker-worker aggression, ovary activation, and production of sterility-appeasement signals may therefore constitute components of a trade-off affecting worker reproduction decisions. By constructing queenless groups of different size and measuring how this affected the parameters above, we found that in all groups aggression was not evenly distributed with the α-worker performing most of the aggressive acts. Moreover, aggression by the α-worker increased proportionally with group-size. However, while in small groups the α-worker monopolized reproduction, in larger groups several workers shared reproduction, creating two worker groups: reproductives and helpers. It appears that despite the increase of aggression, this was evidently not sufficient for the α-worker to monopolize reproduction. If we compare the α-worker to the queen in full-sized colonies it can be hypothesized that worker reproduction in B. terrestris colonies starts due to a gradual increase in the worker population and the queen's inability to physically inhibit worker oviposition. This may shift the trade-off between cost and benefit of worker reproduction and trigger the competition phase.

Multiple UAV Task Assignment using Descriptor Functions

AbstractThe paper presents a preliminary application of a new methodology to the problem of task assignment, for a large number of unmanned vehicles operating in a cooperative and coordinated fashion. The proposed methodology uses the general concept of Descriptor Functions, to establish a relationship between tasks, their priority, and agents or groups of agents forming a large interconnected system. A bio-inspired model of the division of labor in colonies of social agents is used to derive a set of rules at the individual level that gives rise to agent specialization. Preliminary simulations show interesting results, and the potential of the proposed technique.

Transnational Networks and Internal Divisions in Central Mozambique

From 1890 to the 1930s the Portuguese colony of Mozambique developed as a number of institutionally and economically separate regions. The rule of concession companies and the economic ties that developed with neighbouring British colonies meant that internal relations between region and region were often non-existent. After 1930 colonial rule in the Beira District of Mozambique both consolidated and altered people’s relations with the state and the territory. The forced-labour regime was reinforced by limitations on people’s mobility and by the institution of labour reserves, which in turn consolidated the imbalances in the political-economy and created internal boundaries that were often more difficult to cross than those met with on the traditional labour migration routes. These differences were reflected in the internal colonial division of labour between the different economic interests, in the different patterns of employment and treatment of the African workers and in the different way Africans were contracted for labour in the colonial enterprises.

‘Fair Trade’ with Africa

The origin of Africa's current failure to benefit from the expansion of world trade lies in the colonial division of labour, the consequences of which persist in economic structures far more than in other continents. The consequent economic distortions emphasising export of primary products have been preserved by external forces and are now being reinforced by free markets. The ‘fair trade’ concept seeks to ensure a measure of surplus for some producers that the market – dominated by middle-men and oligopsonistic Western corporations – denies them. A leading force in the movement, TWIN, originated in London in the 1980s, and the movement now has worldwide trade approaching £1 billion, mainly in coffee, cocoa and tea, but also in rice and cotton. African countries have been prime beneficiaries. Although growth of ‘fair trade’ is extremely high, it is unlikely ever to displace ‘free trade’ in importance, but it may nevertheless promote a way out of poverty (including dependence on the commodities in question) for many people otherwise trapped in the hangover of colonial power. This may be through gaining increasing control over the commodity chains of which at present they are only the first, fragmented element.

Juvenile Hormone III Influences Task-Specific Cuticular Hydrocarbon Profile Changes in the Ant Myrmicaria eumenoides

We investigated the influence of juvenile hormones (JH) on the composition of cuticular hydrocarbons (CHCs) and the division of labor in colonies of the African ant Myrmicaria eumenoides. CHCs have long been implicated in nestmate recognition in social insect colonies. In M. eumenoides, the CHC profiles also vary with the task performed from brood-tender-type to forager type. The endocrine factors regulating the task allocation as well as the intracolonial recognition cues are not well understood, but JHs are prime candidates. Only JH III was identified in the hemolymph of M. eumenoides workers. Foragers had significantly higher JH III titers than brood tenders. The application of exogenous JH III and a JH analogue (methoprene) to M. eumenoides workers did not result in an observable acceleration of task change in our study. However, longevity of the focus workers, and thus the observational period, was reduced by the applications. Changes from a brood-tender-type to a forager-type CHC profile were accelerated by the application of JH III and methoprene, resulting in brood-tending workers that displayed forager-type CHC profiles. We present the first data supporting that recognition cues of an eusocial Hymenopteran are influenced by JH III, which could thus play a major role in the regulation of the dynamic nature of social insect colonies. JH III is connected to at least two key processes: the acceleration of CHC changes and the more long-term modulation of task shifting. Moreover, this indicates that changes in CHC recognition cues do not trigger task allocation in social insect colonies.

Juvenile hormone, reproduction, and worker behavior in the neotropical social waspPolistes canadensis

Previous studies of the division of labor in colonies of eusocial Hymenoptera (wasps and bees) have led to two hypotheses regarding the evolution of juvenile hormone (JH) involvement. The novel- or single-function hypothesis proposes that the role of JH has changed from an exclusively reproductive function in primitively eusocial species (those lacking morphologically distinct queen and worker castes), to an exclusively behavioral function in highly eusocial societies (those containing morphologically distinct castes). In contrast, the split-function hypothesis proposes that JH originally functioned in the regulation of both reproduction and behavior in ancestral solitary species. Then, when reproductive and brood-care tasks came to be divided between queens and workers, the effects of JH were divided as well, with JH involved in regulation of reproductive maturation of egg-laying queens, and behavioral maturation, manifested as age-correlated changes in worker tasks, of workers. We report experiments designed to test these hypotheses. After documenting age-correlated changes in worker behavior (age polyethism) in the neotropical primitively eusocial wasp Polistes canadensis, we demonstrate that experimental application of the JH analog methoprene accelerates the onset of guarding behavior, an age-correlated task, and increases the number of foraging females; and we demonstrate that JH titers correlate with both ovarian development of queens and task differentiation in workers, as predicted by the split-function hypothesis. These findings support a view of social insect evolution that sees the contrasting worker and queen phenotypes as derived via decoupling of reproductive and brood-care components of the ancestral solitary reproductive physiology.