Defensive traits exhibit an evolutionary trade-off and drive diversification in ants

• Published in: Evolution Vol. 71; no. 2; pp. 315 - 328
• Main Authors: Blanchard, Benjamin D., Moreau, Corrie S.
• Format: Journal Article
• Language: English
• Published: United States Wiley 01.02.2017; Oxford University Press
• Subjects: Ancestral state reconstruction; Animals; Ants - anatomy & histology; Ants - genetics; Ants - physiology; Biological Evolution; defense; Evolutionary biology; evolutionary trade‐off; Formicidae; Genetic diversity; Insects; Life History Traits; ORIGINAL ARTICLE; Phenotype; Phylogenetics; Phylogeny; Sequence Analysis, DNA; trait‐based diversification; Ancestral state reconstruction; Formicidae; trait-based diversification; evolutionary trade-off; defense
• ISSN: 0014-3820; 1558-5646
• DOI: 10.1111/evo.13117

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 tradeoff. 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.