[1] Univ Copenhagen, Dept Biol, Ctr Social Evolut, DK-2100 Copenhagen, Denmark
[2] Univ Sydney, Sch Biol Sci A12, Behav & Genet Social Insects Lab, Sydney, NSW 2006, Australia
[3] Univ Oxford, Dept Zool, Oxford OX1 3PS, England
[4] Univ Leeds, Inst Integrat & Comparat Biol, Leeds LS2 9JT, W Yorkshire, England
[5] Univ Lausanne, Dept Ecol & Evolut, CH-1015 Lausanne, Switzerland
[6] Univ Sussex, Sch Life Sci, Lab Apiculture & Social Insects, Brighton BN1 9QG, E Sussex, England