title: Somatic incompatibility and genetic structure of fungal crops in sympatricAtta colombicaandAcromyrmex echinatiorleaf-cutting ants.
abstract: Obligate mutualistic symbioses rely on mechanisms that secure host-symbiont commitments to maximize host benefits and prevent symbiont cheating. Previous studies showed that somatic incompatibilities correlate with neutral-marker-based genetic distances between fungal symbionts of PanamanianAcromyrmexleaf-cutting ants, but the extent to which this relationship applies more generally remained unclear. Here we showed that genetic distances accurately predicted somatic incompatibility forAcromyrmex echinatiorsymbionts irrespective of whether neutral microsatellites or AFLP markers were used, but that such correlations were weaker or absent in sympatricAtta colombicacolonies. Further analysis showed that the symbiont clades maintained byA. echinatiorandA. colombicawere likely to represent separate gene pools, so that neutral markers were unlikely to be similarly correlated with incompatibility loci that have experienced different selection regimes. We suggest that evolutionarily derived claustral colony founding byAttaqueens may have removed selection for strong incompatibility inAttafungi, as this condition makes the likelihood of symbiont swaps much lower than inAcromyrmex, where incipient nests stay open because queens have to forage until the first workers emerge.
authors: Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
authors: Pepijn W
authors: PW
authors: Kooij
authors: Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
authors: Michael
authors: M
authors: Poulsen
authors: Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
authors: Morten
authors: M
authors: Schiøtt
authors: Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
authors: Jacobus J
authors: JJ
authors: Boomsma
keywords: Attini; Basidiomycota; Commitment; Fungus-growing ants; Interaction; Leucoagaricus gongylophorus; Mutualism; Symbiosis