Cuticular hydrocarbons correlated with reproductive status in a queenless ant

Abstract

Reproductive division of labour is regulated behaviourally in social insects lacking morphologically specialized castes. The directional nature of dominance interactions shows that recognition occurs, but little is known about its basis. In the queenless ant Dinoponera quadriceps, the top worker in the hierarchy (`alpha') mates and produces o¡spring in each colony, while other workers remain virgin. Dominant ants frequently rub one antenna of subordinates against their own cuticle, and alpha and infertile nest-mates consistently di¡er in their relative proportions of the cuticular hydrocarbon 9-hentriacontene (9-C 31 ). The second-ranking`beta' occasionally lays unfertilized eggs and we show that she has less 9-C 31 than the alpha but more than infertile workers. To investigate further the link between 9-C 31 and ovarian activity, we experimentally removed alpha workers (n 11 individuals) and used solid-phase microextraction (SPME) with gas chromatography to measure changes in 9-C 31 on live beta workers which attained alpha status. The proportion of 9-C 31 on the replacement alpha increased signi¢cantly after six weeks, in parallel with her gain in fecundity. We discuss whether 9-C 31 provides honest information about egglaying ability, enabling ants to recognize the di¡erent classes of nest-mates involved in reproductive con£icts. Such fertility cues could reliably underpin the antagonistic interactions occurring in insect societies.

Surface hydrocarbons of queen eggs regulate worker reproduction in a social insect

“…In several ant species, the hydrocarbon profiles of adults correlate with the fertility of individuals, which suggests that hydrocarbons represent a signal regulating reproduction (35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45). In fact, workers can identify gradual differences in the fertility of nestmates in some of these species (42,46) as well as in others (47)(48)(49).…”

Pretender punishment induced by chemical signalling in a queenless ant

“…Low-rankers additionally benefit from preventing replacement, because replacement itself would be costly. In particular, there would be a delay in brood rearing, because it takes approximately 6 weeks for a replacement alpha to mate 6 and activate her ovaries fully 30 . Furthermore, the colony would lose one worker, approximately 1% of the workforce, as the gamergate dies when overthrown 7 .…”

Seasonal activity of Dinoponera quadriceps Santschi (Formicidae, Ponerinae) in the semi-arid Caatinga of northeastern Brazil

“…Few studies have investigated foraging in Dinoponera quadriceps Santschi (Formicidae, Ponerinae) (Araújo & Rodrigues 2006), although the absence of a queen caste has stimulated numerous studies on reproduction and dominance hierarchy in this species (Dantas de Araújo et al 1990aAraújo et al , 1990bHart & Ratnieks 2005;Monnin et al , 2002Monnin et al , 2003Monnin & Ratnieks 1999;Peeters et al 1999 Atlantic Forest, Caatinga and Cerrado areas (Kempf 1971;Paiva & Brandão 1995). D. quadriceps nests are located on the ground, up to a depth of around one meter, with an average of eight chambers, ranging up to 16, and one or more entrances (Dantas de Araújo et al 1990b;Paiva & Brandão 1995;Vasconcellos et al 2004).…”