title: Defensive traits exhibit an evolutionary trade-off and drive diversification in ants.
abstract: Evolutionary biologists have long predicted that evolutionary trade-offs among traits should constrain morphological divergence and species diversification. However, this prediction has yet to be tested in a broad evolutionary context in many diverse clades, including ants. Here, we reconstruct an expanded ant phylogeny representing 82% of ant genera, compile a new family-wide trait database, and conduct various trait-based analyses to show that defensive traits in ants do exhibit an evolutionary trade-off. In particular, the use of a functional sting negatively correlates with a suite of other defensive traits including spines, large eye size, and large colony size. Furthermore, we find that several of the defensive traits that trade off with a sting are also positively correlated with each other and drive increased diversification, further suggesting that these traits form a defensive suite. Our results support the hypothesis that trade-offs in defensive traits significantly constrain trait evolution and influence species diversification in ants.
authors.affiliation: Committee on Evolutionary Biology, University of Chicago, Chicago, Illinois, 60637.|Department of Science and Education, Integrative Research Center, Field Museum of Natural History, Chicago, Illinois, 60605.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Blanchard
authors.affiliation: Department of Science and Education, Integrative Research Center, Field Museum of Natural History, Chicago, Illinois, 60605.
authors.forename: Corrie S
authors.initials: CS
authors.lastname: Moreau
mesh_terms: D000818:Animals; D001000:Ants / Q000033:anatomy & histology* / Q000235:genetics / Q000502:physiology*; D005075:Biological Evolution; D000071421:Life History Traits; D010641:Phenotype; D010802:Phylogeny; D017422:Sequence Analysis, DNA
keywords: Ancestral state reconstruction; Formicidae; defense; evolutionary trade-off; trait-based diversification