Annual cycle of nest composition in the queen‐dimorphic weaver ant P olyrhachis australis M ayr, 1870 ( H ymenoptera: F ormicidae) in northern Q ueensland

The A ustralian spiny weaver ant P olyrhachis australis   M ayr, 1870 is an arboreal formicine ant that constructs nests using silk and particulate matter (carton). Between S eptember 2009 and D ecember 2012, the contents of 181 P . australis nests were recorded. Of these, 14% were queenless, 21% were monogynous and 65% were polygynous. Monogynous nests had more than double the number of brood per queen, but were outnumbered nine to one by polygynous nests in J anuary, just after the reproductive phase and before the heaviest rain of the wet season. This proportion fell close to equal before the start of the next reproductive phase in S eptember, suggesting attrition of queens by competition during the ergonomic phase of the annual cycle that peaks in M ay. The reproductive phase of the annual cycle started with the appearance of new gynes in S eptember through N ovember. Male production increased in O ctober, peaked in N ovember and D ecember, and declined in J anuary. Hence, gynes were produced before males (protogyny). The pupal sex ratio was heavily male‐biased during this time. Males continued to be produced in relatively low numbers throughout the year, supporting (along with other evidence including nest‐size limiting habitat structure) the view that P . australis colonies are polygynous and polydomous. The polygynous status of most nests may have arisen more from retention of queens in the mother nest than from adoption. Queen size was bimodal and the microgyne–macrogyne dimorphism may point to a mixed strategy of nest/colony founding whereby macrogynes typically fly and establish colonies independently, while microgynes typically walk to new nest sites and found nests dependently under the protection of a retinue of workers. In support of this inference, all of 49 queens which displayed brachyptery or other wing malformations were microgynes.