Lifespan and Reproduction in a Queenless Ant

摘要

The costs of reproduction are a central issue in theories of life history evolution. Particularly, tradeoffs are expected between different fitness traits, such as reproduction and adult longevity. Empirical studies indicate that reproductive efforts during an earlier life stage may indeed reduce an individual's fitness later in life. In Drosophila fruit flies, for example, egg production and courting appear to shorten a female's life span and, similarly, longevity is re-duced by mating in the hermaphrodi-tic nematode Caenorhabditis elegans .The correlation between reproduction and longevity appears to be com-pletely different in ants, where the adult life span of reproductive queens by far exceeds that of nonreproduc-tive workers . Though genetically identical, queens and workers typical- ly differ strongly in their morphology and ontogeny, which makes it difficult to investigate the causes of different longevity in the two female castes. We here show, however, that repro-ductives also live longer than nonre-productives when they are develop-mentally and morphologically indistinguishable.