Social influence on age and reproduction: reduced lifespan and fecundity in multi‐queen ant colonies

Abstract

Evolutionary theories of ageing predict that life span increases with decreasing extrinsic mortality, and life span variation among queens in ant species seems to corroborate this prediction: queens, which are the only reproductive in a colony, live much longer than queens in multi‐queen colonies. The latter often inhabit ephemeral nest sites and accordingly are assumed to experience a higher mortality risk. Yet, all prior studies compared queens from different single‐ and multi‐queen species. Here, we demonstrate an effect of queen number on longevity and fecundity within a single, socially plastic species, where queens experience the similar level of extrinsic mortality. Queens from single‐ and two‐queen colonies had significantly longer lifespan and higher fecundity than queens living in associations of eight queens. As queens also differ neither in morphology nor the mode of colony foundation, our study shows that the social environment itself strongly affects ageing rate.

Convergent development of ecological, genetic, and morphological traits in native supercolonies of the red ant Myrmica rubra

“…The ecological, genetic, and morphological differences between monogynous, polygynous, and supercolony nest types that we found confirm that social syndromes coexist within populations, but with overlap in certain traits. Other studies that compared monogyny and polygyny syndromes in sympatry found similar results, with only some life-history traits being different (Chapuisat et al 2004;Rosset and Chapuisat 2006;Bargum et al 2007;Meunier and Chapuisat 2009;Reber et al 2010;Schrempf et al 2011). Our finding that there is no difference in individual body sizes between polygynous and supercolony nests suggests that living in supercolonies does not necessarily lead to further morphological changes, so that nests with stable polygyny may all be "incipient supercolonies" with the potential to develop into a long-lived supercolony when conditions allow rapid growth by colony budding.…”

“…The polygyny and supercolony syndrome implies that individuals are smaller, more likely to disperse over short rather than long distances, shorter-lived, and less fecund (when queens) compared to individuals in monogynous colonies (Sundström 1995a, b;Bourke and Franks 1995;Kikuchi et al 1999;Peeters 2001;Chapuisat et al 2004; Bargum et al 2007;Helanterä et al 2009;Schrempf et al 2011;Cronin et al 2012). Also, the number of nests per colony tends to increase, with monodomy (one nest per colony) prevailing when colonies are monogynous and the frequency of polydomy (multiple nests per colony) increasing with the recurrent adoption of new queens (Keller 1993;Bourke and Franks 1995;Heinze and Foitzik 2009;Boomsma et al 2014).…”

Mating with an allopatric male triggers immune response and decreases longevity of ant queens

“…Previous studies did not reveal worker discrimination among differently fecund queens (Schrempf et al . , ), and although productivity differences among differently mated Okinawa queens were small, lifespan differences matched those of Ilhéus queens, indicating that queen physiology is affected by mating combination and not by workers.…”

Reproduction Is Associated with a Tissue-Dependent Reduction of Oxidative Stress in Eusocial Female Damaraland Mole-Rats (Fukomys damarensis)

“…There is evidence that lifespan is not traded off against reproduction in some social insect species [41], [68], [86], [87], [88] and in Ansell's mole-rats it has been proposed that, given no difference in activity or intrinsic quality between reproductive and non-reproductive individuals, reproduction may drive increased longevity in breeding females [46]. Since the reproductive success of a eusocial colony is almost solely dependent on the condition of the queen, Damaraland mole-rats and other eusocial species may have acquired adaptations to ensure or enhance survival that are expressed when a female obtains dominance and commences breeding.…”