Month: September 2022

This is almost all we need to know about our planet. " " https://lnkd.in/dSRsurj View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend and concludes this weekend on EO Wilson’s paper on eusocial insect evolution. The transition to eusociality is the concern of his thinking in this work, and he methodically traces the options and arguments. Here is a leading ant biologists deducting evolutionary history from the available facts, a beautiful piece. View in LinkedIn

GENE FIXATION. “In crossing the line to eusociality, a single allele that disposes daughters to stay could be fixed in the populations at large if the advantage of the little group over solitaires sufficiently outweighs the advantage of each worker leaving to try on its own.” https://lnkd.in/drgWvGT View in LinkedIn

SELECTIVE FLIGHT. “As an overarching principle, the final step to eusociality can occur with the substitution of only one allele or a small set of alleles. Throughout the great diversity of living ant species, for example, the coexistence of winged reproductive females and wingless worker females is a basic trait of colonial life. Judging from the phylogenetically well-separated flies (order Diptera) and butterflies (order Lepidoptera), wing development is directed throughout the winged insects by an unchanged regulatory gene network.” https://lnkd.in/drgWvGT View in LinkedIn

WINGLESS WORKERS. “More than 110 million years ago, the earliest ants (or their immediate ancestors) altered the regulatory network of wing development in such a way that some of the genes could be shut down under the influence of diet or some other environmental factor. Thus was produced a wingless worker caste.” https://lnkd.in/drgWvGT View in LinkedIn

GENE SEARCH. “The exact nature of the genetic step to the earliest degree of eusociality is still unknown, unlike the cases of winglessness and colony odor, but it is immediately accessible to genetic research. Hunt and Amdam (2005) have suggested that the genetic base of the flexible worker-versus-queen difference in Polistes paper wasps is the same as the genetically based developmental physiology that regulates diapause in solitary Hymenoptera.” https://lnkd.in/drgWvGT View in LinkedIn

MECHANISTIC THEORIES. “Or ensemble of alleles that appears by mutation and then spreads from low frequencies by group selection. Instead, the key polyphenic allele (or allele ensemble) may in theory be previously fixed in the population by individual direct selection (as opposed to group selection), with solitary behavior the norm in most environments and eusocial behavior in other, rare and extreme environments. With a shift in the available environment in space or time, eusocial behavior would become the norm.” https://lnkd.in/drgWvGT View in LinkedIn

TRANSITION IN PROCESS. “That a species on the brink of eusociality might follow this path is shown by the Japanese stem-nesting xylocopine bee Ceratina flavipes. The vast majority of the females provision their nests with pollen and nectar as solitary foundresses, but in slightly more than 0.1% of the nests, two individuals cooperate. When this happens, the pair divides the labor: one lays the eggs and guards the nest entrance while the other forages.” https://lnkd.in/drgWvGT View in LinkedIn

GROUP SELECTION. “Although some individual direct selection may play an auxiliary role in the origin of eusociality, the force that targets the maintenance and elaboration of eusociality is by necessity environmentally based group selection, which acts upon the emergent traits of the group as a whole. An examination of the behavior of the most primitively eusocial ants, bees, and wasps shows that these traits are initially dominance behavior, reproductive division of labor, and, very likely, some form of alarm communication mediated by pheromones.” https://lnkd.in/drgWvGT View in LinkedIn

HYBRID TRAITS. “A species in the earliest stage of eusociality is a kind of neurogenetic chimera: on the one hand, the newly emergent traits favor the group, while on the other hand, much of the rest of the genome, having been the target of individual direct selection over millions of years, favors personal dispersal and reproduction.” https://lnkd.in/drgWvGT View in LinkedIn