Data from: Evolutionary déjà vu? A case of convergent evolution in an ant-plant association

Obligatory ant-plant symbioses often appear to be single evolutionary
shifts within particular ant lineages; however, convergence can be
revealed once natural history observations are complemented with molecular
phylogenetics. Here we describe a remarkable example of convergent
evolution in an ant-plant symbiotic system. Exclusively arboreal,
Myrmelachista species can be generalized opportunists nesting in several
plant species or obligately symbiotic, live-stem nesters of a narrow set
of plant species. Instances of specialization within Myrmelachista are
known from northern South America and throughout Middle America. In Middle
America, a diverse radiation of specialists occupies understory treelets
of lowland rainforests. The morphological and behavioural uniformity of
specialists suggests that they form a monophyletic assemblage,
diversifying after a single origin of specialization. Using ultraconserved
element phylogenomics and ancestral state reconstruction, we show that
shifts from opportunistic to obligately symbiotic evolved independently in
South and Middle America. Furthermore, our analyses strongly support a
remarkable case of convergence within the Middle American radiation, with
two independently evolved specialist clades, arising nearly simultaneously
from putative opportunistic ancestors during the late Pliocene. This
repeated evolution of a complex phenotype suggests similar mechanisms
behind trait shifts from opportunists to specialists, generating further
questions about the selective forces driving specialization.