Unequal resource allocation among colonies produced by fission in the antCataglyphis cursor

Abstract

How organisms allocate limited resources to reproduction is critical to their fitness. The size and number of offspring produced have been the focus of many studies. Offspring size affects survival and growth and determines offspring number in the many species where there is a trade-off between size and number. Many social insects reproduce by colony fission, whereby young queens and accompanying workers split off from a colony to form new colonies. The size of a new colony (number of workers) is set at the time of the split, and this may allow fine tuning size to local conditions. Despite the prevalence of colony fission and the ecological importance of social insects, little is known of colony fission except in honey bees. We studied colony fission in the ant Cataglyphis cursor. For clarity, "colony" and "nest" refer to colonies before and after colony fission, respectively (i.e., each colony fissions into several nests). The reproductive effort of colonies was highly variable: Colonies that fissioned varied markedly in size, and many colonies that did not fission were as large as some of the fissioning colonies. The mother queen was replaced in half of the fissioning colonies, which produced 4.0 +/- 1.3 (mean +/- SD) nests of markedly varied size. Larger fissioning colonies produced larger nests but did not produce more nests, and resource allocation among nests was highly biased. When a colony produced several nests and the mother queen was not replaced, the nest containing the mother queen was larger than nests with a young queen. These results show that the pattern of resource allocation differs between C. cursor and honey bees. They also suggest that C. cursor may follow a bet-hedging strategy with regard to both the colony size at which fission occurs and the partitioning of resources among nests. In addition, colony fission may be influenced by the age and/or condition of the mother queen, and the fact that workers allocating resources among nests have incomplete knowledge of the size and number of nests produced. These results show that the process of colony fission is more diverse than currently acknowledged and that studies of additional species are needed.

At the brink of supercoloniality: genetic, behavioral, and chemical assessments of population structure of the desert ant Cataglyphis niger

“…Monogynous species may be organized as independent colonies (Leniaud et al, 2011) while others are organized in polydomous colonies, with one central nest holding the queen and the rest of the nests function as queenless satellites (Dahbi et al, 1997). In contrast to the usual association between monogyny and longrange nuptial flights, young queens of the monogyne C. cursor and C. floricola mate close to their natal nest and colony reproduction proceeds by fission (Lenoir et al, 1988;Hardy et al, 2008;Amor et al, 2011;Chéron et al, 2011). Queens of some species are singly mated (Eyer et al, 2012;Leniaud et al, 2012), whereas in other species they are obligatory multiply mated (Timmermans et al, 2008(Timmermans et al, , 2010Pearcy et al, 2009).…”

Fertile diploid males in the ant Cataglyphis cursor: a potential cost of thelytoky?

“…Second, when colonies reproduce by dependent colony foundation (the queen founds a new colony with the help of workers, Cronin et al 2013), as is the case for most known thelytokous ants, the number of colonies produced is more limited by the worker force available than by the number of young queens produced. Indeed, in most colonies of C. cursor, the number of young queens produced exceeds the number of offspring colonies (Chéron et al 2011a). Hence, it is unlikely that DMP would reduce the number of young queens sufficiently to affect the number of offspring colonies.…”

Effects of division of labour on immunity in workers of the ant Cataglyphis cursor

“…Colonies are exclusively founded by colony fission that occurs just after sexual production towards the end of May (Chéron et al, 2011). From May to September, workers are produced until colonies enter into hibernation without any brood.…”