Current Status of a Model System: The Gene Gp-9 and Its Association with Social Organization in Fire Ants

The Gp-9 gene in fire ants represents an important model system for studying the evolution of social organization in insects as well as a rich source of information relevant to other major evolutionary topics. An important feature of this system is that polymorphism in social organization is completely associated with allelic variation at Gp-9, such that single-queen colonies (monogyne form) include only inhabitants bearing B-like alleles while multiple-queen colonies (polygyne form) additionally include inhabitants bearing b-like alleles. A recent study of this system by Leal and Ishida (2008) made two major claims, the validity and significance of which we examine here. After reviewing existing literature, analyzing the methods and results of Leal and Ishida (2008), and generating new data from one of their study sites, we conclude that their claim that polygyny can occur in Solenopsis invicta in the U.S.A. in the absence of expression of the b-like allele Gp-9b is unfounded. Moreover, we argue that available information on insect OBPs (the family of proteins to which GP-9 belongs), on the evolutionary/population genetics of Gp-9, and on pheromonal/behavioral control of fire ant colony queen number fails to support their view that GP-9 plays no role in the chemosensory-mediated communication that underpins regulation of social organization. Our analyses lead us to conclude that there are no new reasons to question the existing consensus view of the Gp-9 system outlined in Gotzek and Ross (2007)

Corporate Tax Avoidance And Political Action Committee Contributions: An Empirical Analysis

This study examines the relationships between corporate tax avoidance and Political Action Committee (PAC) contributions.  The study hypothesizes that corporate PAC contributions influence corporate tax avoidance behavior.  However, the tax savings associated with corporate PAC contributions do not increase monotonically because of significant wealth transfers from voters to corporations and the subsequent brokering behavior of politicians in favor of the voter constituency.  The results are consistent with our hypothesis

A 4D natural selection model illuminates the enigma of altruism in the Shedao pit viper

Cooperation, Evolution, Mutualism, Island biogeography, Complexity, A13, B49, B59, C72, C91, D63, D64, J16, Z13,

Ambidextrous Mandibles in the Fire Ant Solenopsis invicta.

The elongation and sharp teeth of ant mandibles are considered important adaptations that have contributed to ants successful colonization of terrestrial habitats worldwide. In extant ant species, mandibles function as hunting and defense weapons, as well as multipurpose tools for excavating soil, cutting leaves, capturing and butchering prey, harvesting seeds, and transporting brood. This article reports that the mandibles in the red imported fire ant, Solenopsis invicta Buren, are functionally ambidextrous. Individuals opened and closed each mandible in synchrony or independently depending on the requirement of the task at hand. Upon completion of a task, individuals were without a preference in the orientation of mandible overlap—right overlap or left overlap. Orientation of mandible overlap before and after performing a task was also examined in nine other ant species. No overlap orientation preference was observed in any of these ant species, suggesting that ambidextrous mandibles are a universal trait in ants. These findings add an increment of knowledge to the diverse functions of ant mandibles