Month: September 2022

HIGH BAR. “For the binding effects of group selection to outweigh the dissolutive effects of individual direct selection, the candidate insect species evidently must have only a very short evolutionary distance to travel, such that no more than a very small number of emergent traits are needed to form a eusocial colony. The reduction of that distance is achieved by a particular set of preadaptations. The rarity of these preadaptations, in just the right combination, when added to the high bar to eusociality set by countervailing individual direct selection, may be enough to explain the general phylogenetic rarity of eusociality.” https://lnkd.in/drgWvGT View in LinkedIn

THE TRANSITION STEP. “The only genetic change needed to cross the threshold to the eusocial grade is possession by the foundress of an allele that holds the foundress and her offspring to the nest. The preadaptations provide the phenotypic flexibility required for eusociality, as well as the key emergent traits arising from interactions of the group members. Group (colony-level) selection then immediately acts on both of these traits.” https://lnkd.in/drgWvGT View in LinkedIn

SUPPOSEDLY IMPOSSIBLE NEGATIVE MASS. “The crucial breakthrough by Mbarek and Paranjape is to show that negative mass can produce a reasonable Schwarzschild solution without violating the energy condition. Their approach is to think of negative mass not as a solid object, but as a perfect fluid, an otherwise common approach in relativity.” https://lnkd.in/dBWe6d4 View in LinkedIn

Fabulous and abundant wild garlic crops are carpeting the woods just now. View in LinkedIn

EARLY TRANSITION. “In the earliest stage of eusociality, the offspring remaining in the nest would be expected to assume the worker role, in conformity with the preexisting behavioral ground rule inherited from the pre-eusocial ancestor. Subsequently, a morphological worker caste can emerge by a further genetic change in which the expression of genes for maternal care is rerouted to precede foraging, thus reversing the normal sequence in the adult developmental ground plan of the ancestor.” https://lnkd.in/drgWvGT View in LinkedIn

TRANSITION MADE. “Passing the point of no return. The rerouting is programmed to remain part of the phenotypic plasticity of the alleles that prescribe the overall ground plan. This origin of an anatomically distinct worker caste appears to mark the “point of no return” in evolution, at which eusocial life becomes irreversible.” https://lnkd.in/drgWvGT View in LinkedIn

GENETIC VARIABILITY. “Greater genetic variability in the workforce, and hence lower relatedness, can be favored by group selection. In the harvester ant Pogonomyrmex occidentalis, for example, colonies with greater genetic variation have overwhelmingly higher rates of growth and reproduction than those with less variation. This rise in fitness may be due to the enhancement of labor division by spreading tasks among workers with genetic predispositions to specialization.” https://lnkd.in/drgWvGT View in LinkedIn

DISEASE RESISTANCE. “As an alternative explanation, increased genetic diversity among workers might easily arise as a means of improving overall resistance to disease. Such a correlation between genetic diversity and disease resistance has been found in colonies of the leaf-cutter Acromyrmex echinatior in the control of a virulent soil fungus.” https://lnkd.in/drgWvGT View in LinkedIn

INBREEDING. “A final force that could drive incipient colonies away from a high degree of relatedness during evolution might be the loss of genetic fitness by inbreeding. In communal associations of bees, group members occupy a single nest. They cooperate in brood care, but without surrendering their personal reproduction. This form of sociality, which occurs in all six of the taxonomic families of bees, could lead to eusociality by the subordination of some of the nest occupants, although no such shift has yet been documented.” https://lnkd.in/drgWvGT View in LinkedIn

NULL ORIGIN OF EUSOCIALITY. “In summary, the known background biology of the eusocial insects, in particular the hymenopterans, gives no reason to presuppose that pedigree kinship is a key causative element in the origin and early evolution of eusociality.” https://lnkd.in/drgWvGT View in LinkedIn