Cofoundresses of the desert fungus garden ant Acromyrmex versicolor exhibit a forager specialist who subsumes all foraging risk prior to first worker eclosion (Rissing et al. 1989). In an experiment designed to mimic a "cheater" who refuses foraging assignment when her lot, cofoundresses...

A simple variant of trait group selection, employing predators as the mechanism underlying group selection, supports contingent reproductive suicide as altruism (i.e., behavior lowering personal fitness while augmenting that of another) without kin assortment. The contingent suicidal type may...