Labor In Insect Societies Research Articles

Fixed Response Thresholds and the Regulation of Division of Labor in Insect Societies

We introduce a simple mathematical model of regulation of division of labor in insect societies based on fixed-response thresholds. Individuals with different thresholds respond differently to task-associated stimuli. Low-threshold individuals become involved at a lower level of stimulus than high-threshold individuals. We show that this simple model can account for experimental observations of Wilson (1984), extend the model to more complicated situations, explore its properties, and study under what conditions it can account for temporal polyethism.

Response threshold reinforcements and division of labour in insect societies

A model of division of labour in insect societies, based on variable response thresholds is introduced. Response thresholds refer to the likelihood of reacting to task–associated stimuli. Low–threshold individuals perform tasks at a lower level of stimulus than high–threshold individuals. Within individual workers, performing a given task induces a decrease in the corresponding threshold, and not performing the task induces an increase in the threshold. This combined reinforcement process leads to the emergence of specialized workers, i.e. workers that are more responsive to stimuli associated with particular task requirements, from a group of initially identical individuals. Predictions of the dynamics of task specialization resulting from this model are presented. Predictions are also made as to what should be observed when specialists of a given task are removed from the colony and reintroduced after a varying amount of time: the colony does not recover the same state as that prior to the perturbation, and the difference between before and after the perturbation is more strongly marked as the time between separation and reintroduction increases.

Quantitative study of the fixed threshold model for the regulation of division of labour in insect societies

A simple model of regulation of division of labour in insect societies is introduced and studied. Individuals are assumed to respond to task-related stimuli with response thresholds. When the intensity of a particular stimulus exceeds an individual9s response threshold, the individual engages in task performance with high probability, and successful task performance reduces the intensity of the stimulus. If individuals belonging to different (physical or behavioural) castes have different response thresholds, and if thresholds are assumed to remain fixed over the timescales of experiments, this model can account for some observations on ant species of Pheidole (Wilson 1984).

Regulation Of Division Of Labor In Insect Societies

With a growing world population and increasingly demanding consumers, the production of sufficient protein from livestock, poultry, and fish represents a serious challenge for the future. Approximately 1,900 insect species are eaten worldwide, mainly in ...Read More

Regulation of division of labor in insect societies.

Division of labor is fundamental to the organization of insect societies and is thought to be one of the principal factors in their ecological success (174). Division of labor in insect colonies is characterized by two features: (a) different activities are performed simultaneously by (b) groups of specialized individuals, which is assumed to be more efficient than if tasks are performed sequentially by unspecialized individuals (55, 56, 93, 106; but see 37). A key feature of the division of labor in insect colonies is its plasticity. Colonies respond to changing internal and external conditions by adjusting the ratios of individual workers engaged in the various tasks. This is accomplished in large part via the behavioral flexibility of the individual workers themselves. Worker behavioral flexibility contributes to the reproductive success of a colony by enabling it to continue to grow, develop, and ultimately produce a new generation of reproductive males and females despite changing colony conditions. Sensitivity to change within a structured labor system is important to social organization, but only now are we beginning to understand this concept. The

Quantifying tasks and roles in insect societies

When setting out a framework for the exploration of a subject, it is necessary to define terms to represent specific concepts, and to refine them as knowledge of the subject grows. It is a great advantage if stipulative definitions are also operational definitions, since this makes methods of quantification obvious. The concepts of tasks and roles are central to studies of organization of labour in insect societies, but their application has sometimes been problematic. Here their definitions are reviewed, and appropriate methods of quantification and analysis are outlined. These involve correspondence analysis and Markov chain analysis of transition probability matrices to study the organization of behaviour into tasks, and correspondence analysis of ethograms made by scan sampling to investigate the roles filled by the workers.