Theoretical and Empirical Support for Bilateral Decrementation

Abstract

The concept of \"genetic bandwagoning\" is introduced. In genetic bandwagoning, a bandwagoning allele evaluates the outlook for lineage fitness of the individual holding the allele. If its holders lineage fitness figures to be low, the bandwagoning allele induces its holder to relinquish some, or all, of the holders own resources (e.g., food, territory, mates), which are then used by individuals that happen to be nearby. While some nearby individuals may not possess a copy of the bandwagoning allele, it is likely, if assortment is sufficiently positive, that numerous individuals do and most of those that do have a better lineage fitness outlook than that of the individual that was induced to forfeit the resources, since the inducement is contingent upon a poor lineage fitness outlook. Due to their better lineage fitness outlook, the nearby individuals make better usage of the resources than the forfeiting individuals would have and the ratio between the quantity of descendants nearby individuals produce with the resources and the quantity of descendants that would have been produced by the forfeiting individuals tends to increase with each generation due to multiple reasons examined in section 2. If assortment is sufficiently positive, more copies of the allele are produced over the ensuing generations than if the resources had not been forfeited, as the allele is selected by \"jumping on the bandwagon\" of these fit lineages that use the resources.\n\nTwo ways to bandwagon are introduced: resonation and reservation. In resonation, the bandwagoning allele accomplishes the two steps of bandwagoning--1) evaluating its holders lineage fitness outlook and 2) inducing a holder with a low (i.e., poor) outlook to relinquish resources--sequentially. The necessity for reservation occurs because a lineages fitness outlook can depend upon aspects of quality which are difficult to evaluate during a generation in which many individuals are able to avoid death or serious harm. In reservation, a bandwagoning allele solves this problem of evaluating quality by inducing its holder to reserve from (i.e., withhold) some of its ability to survive against one or more natural enemies, particularly predators or parasites: An individual that can remain healthy in spite of reserving from its ability to survive predators or parasites is likely to have genes that enable its descendants to survive when the predator or parasite threat is more severe; however, if the individual perishes or becomes sick as a result of reservation, its lineage fitness outlook is determined to be low and the relinquishment of resources occurs with this same perishing or sickness. That is, the individuals perishing or sickness due to reservation serves simultaneously: 1) to identify that individual as having a low lineage fitness outlook and 2) as the source of relinquishing the individuals resources on the basis of this low lineage fitness outlook.\n\nGenetic bandwagoning constitutes a novel mechanism for the evolution of cooperation. Numerous paradoxes can be explained by the actions of bandwagoning alleles that use a combination of resonation and reservation, including the phenotypic cooccurrences of robust defenses against parasites and depressive symptoms; phenotypic cooccurrences of robust defenses against parasites and photosynthetic costs; phenotypic cooccurrences of susceptibility to parasites and androgenic benefits; the maintenance of honest signals when there are opportunities to cheat; the forfeiture of reproductive opportunities by functionally capable individuals; and the differential nurturing of offspring.