The evolution of weaponry occurs less frequently in females than in males and is most often important for protecting ecological resources or offspring rather than winning mates. The purpose of female weapons is often confounded by the presence of similar weapons in males, so cases where only females need weapons provide important tests of our understanding of how and why weapons evolve. In some populations of the ant, Messor pergandei (Mayr), newly mated queens initiate new nests in social groups that subsequently break down when queens engage in battles for control. The incipient social environment differs geographically, so that lethal fighting occurs in some populations but not others. Consistent with the hypothesis that queens in populations where lethal fighting occurs should show selection for weaponry (broad heads and strong mandibles), we found that heads of queens from sites where lethal fighting occurs were broader than those at sites with non-fighting queens and a site with solitary queens. Evolution of weaponry is specific to queens, because regression results from workers often did not follow this pattern.

Five new species of the endemic giant pill-millipede genus Zoosphaerium from Madagascar are described: Z. muscorum sp. n., Z. bambusoides sp. n., Z. tigrioculatum sp. n., Z. darthvaderi sp. n., and Z. heleios sp. n. The first three species fit into the Z. coquerelianum species-group, where Z. tigrioculatum seems to be closely related to Z. isalo Z. bilobum Wesener, 2009. Z. tigrioculatum is also the giant pill-millipede species currently known from the highest elevation, up 2000 m on Mt Andringitra. Z. muscorum and Z. darthvaderi were both collected in mossy forest at over 1000 m (albeit at distant localities), obviously a previously undersampled ecosystem. Z. darthvaderi and Z. heleios both possess very unusual characters, not permitting their placement in any existing species-group, putting them in an isolated position. The females of Z. xerophilum Wesener, 2009 and Z. pseudoplatylabum Wesener, 2009 are described for the first time, both from samples collected close to their type localities. The vulva and washboard of Z. pseudoplatylabum fit very well into the Z. platylabum species-group. Additional locality and specimen information is given for nine species of Zoosphaerium: Z. neptunus

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