Month: September 2022

TRANSITIONAL STRUCTURES. “A second preadaptation that favors the transition to eusociality is the propensity, documented in solitary bees, to behave like eusocial species when forced together experimentally.” https://lnkd.in/drgWvGT View in LinkedIn

LABOUR DIVISION. “The division of labor appears to be the result of a preexisting behavioral ground plan, in which solitary individuals tend to move from one job to another after the first is completed. In eusocial species, the algorithm is transferred to the avoidance of a job already being filled by another nestmate. It is evident that progressively provisioning bees and wasps are “spring-loaded” (strongly predisposed, with a trigger) for a rapid shift to eusociality, once group selection favors the change.” https://lnkd.in/drgWvGT View in LinkedIn

DIVISION OF LABOR. “The results of the forced-group experiments fit the fixed-threshold model of the origin of labor division proposed for the emergence of the phenomenon in established insect societies. The model posits that variation, sometimes genetic in origin and sometimes purely phenotypic, exists in the response thresholds associated with various tasks.” https://lnkd.in/drgWvGT View in LinkedIn

TASK ALLOCATION. “When two or more individuals interact, those with the lowest threshold are the first to begin the task. The activity inhibits their partners, who are then more likely to move on to whatever other tasks are available. Thus, once again, the group impact of a single phenotypically flexible allelic change that inhibits dispersal from the natal nest would seem to be enough to carry preadapted species across the eusocial threshold.” https://lnkd.in/drgWvGT View in LinkedIn

PREADADAPTATION. “The key preadaptation for eusociality in the social Hymenoptera is progressive provisioning, a behavior that in solitary species arises by individual direct selection.” https://lnkd.in/drgWvGT View in LinkedIn

BROOD TIMING. “Simultaneous progressive provisioning, by which multiple larvae are reared at the same time, is especially potent as a preadaptation in the Hymenoptera. From this wholly solitary adaptation, it is but one short step in evolution for adult offspring to remain at the nest and help their mother raise siblings, instead of dispersing to rear brood of their own. In that generation the eusocial colony originates. Then and thereafter, group selection proceeds, uniquely targeting the emergent traits created by the interaction of the colony members.” https://lnkd.in/drgWvGT View in LinkedIn

WORKER CASTE. “Altruism and eusociality are thus evidently born from the appearance of a phenotypically flexible eusocial allele (or ensemble of such alleles) in a progressively provisioning mother, and from group selection acting on emergent group traits, which are socially binding and sufficiently powerful to overbalance the dissolutive effects of individual direct selection. One small step, so to speak, for a newly created worker caste, one giant leap for the Hymenoptera.” https://lnkd.in/drgWvGT View in LinkedIn

TRANSITIONS. “Exactly what kind of group selection drives the species across the threshold? Concrete examples of this adaptation and the transition it affords are provided by halictid sweat bees and polistine wasps. In one recently documented case, two species of sweat bees that switched from collecting the pollen of many plant species to collecting pollen from only a few plant species also reverted from a primitively eusocial life to a solitary life.” https://lnkd.in/drgWvGT View in LinkedIn

REVERSALS. “Evolution in the reverse direction is easily conceivable, and very likely occurred: adaptation to a broader array of food plants set the stage for multiple generations, and thence for overlapping generations in the same nest.” https://lnkd.in/drgWvGT View in LinkedIn

SO ENDS this first of two weekends on a wonderful EO Wilson article about the evolution of eusocial insect societies. Insect societies are far older than human societies and very diverse in structure. How these groups are organized, and what ramifications they have, may shed some light on future human societies, after our initial rather blundering experiments on the subject. View in LinkedIn