Aging and Reproduction in Social Insects – A Mini-Review

Abstract

Perennial social insects are characterized by the extraordinarily long lifespan of their reproductive females, which may be tens or hundreds of times larger than that of non-social insects of similar body size and also greatly surpasses that of conspecific non-reproductives. Evolutionary theories of aging explain this phenomenon from the low extrinsic mortality queens experience once they have successfully established their colony. The aim of our review is to summarize recent findings on the ultimate and proximate causes of increased queen longevity in social insects, in particular ants and honey bees. While progress is being made in elucidating the interrelations between the vitellogenin, juvenile hormone, fecundity, and senescence, we feel that the explanation for the comparatively short lifespan of queens in multi-queen societies is as yet not satisfactory and needs further attention, both concerning its proximate and ultimate basis.

Identification of an ant queen pheromone regulating worker sterility

“…Queen-specific cuticular hydrocarbons are typically methylated alkanes or alkenes, which are thought to confer inferior protection against desiccation compared with the hypothetically ancestral compounds, linear alkanes (Monnin 2006;Le Conte & Hefetz 2008). Also, reproductive development in insects is correlated with hormone titres (Heinze & Schrempf 2008) as well as surface chemicals; hormones influence condition and survival, for example through effects on immune function (Rolff & Siva-Jothy 2002) and anti-oxidant activity (Heinze & Schrempf 2008). Therefore, the costs of pheromone synthesis might arise from the physiologically expensive hormone levels required for their production (as suggested for sexual signals; Folstad & Karter 1992), although further biochemical data are required to test this hypothesis.…”

Honest and dishonest communication in social Hymenoptera

“…Almost nothing is known about the energetics of pheromone production in social insects, and as the traditional trade-off between longevity and reproductive efforts is turned upside down in perennial social insects (Heinze and Schrempf, 2008) it will be difficult to determine how costly it is to produce queen signals. Yet, considerable costs appear to be born by those individuals that, in the presence of one or several fully fertile reproductives, change their chemical bouquet as they attempt to usurp the position of the reproductive or to start laying eggs.…”

Variation in male body size and reproductive allocation in the leafcutter ant Atta colombica: estimating variance components and possible trade-offs

“…This suggests that the characteristics of their morphology and sexual functioning have been shaped primarily by sexual selection, rather than natural or kin selection (Baer, 2010), but explicit studies of the possible trade-offs involved in maximizing ant male reproductive success have been scant (Boomsma et al, 2005). Exceptions are a recent study on honeybees showing male size to be an important predictor of reproductive success (Couvillon et al, 2010), as well as studies on Cardiocondyla male ants, which are peculiar because they are long-lived and spermatogenesis continues throughout adult life (Heinze and Hölldobler, 1993;Heinze and Schrempf, 2008) in contrast to all other known ants where sperm production ceases during the pupal stage (Hölldobler and Bartz, 1985).…”