Repeated evolution of seed dispersal by ants: 100 independent origins of Myrmecochory

Seed dispersal is a fundamental life history trait in plants … Myrmecochory (seed dispersal by ants) is mediated by elaiosomes, i.e., lipid-rich seed appendages that attract ants and serve as rewards for dispersal.

We found that myrmecochory is present in at least 11 000 species or 4.5% of all species, in 334 genera or 2.5% of all genera and in 77 families or 17% of all families of angiosperm plants. We identified at least 101, but possibly up to 147, independent origins of myrmecochory. 

Most myrmecochorous lineages were Australian, South African or northern temperate (Holarctic). A mapping of families containing myrmecochorous genera on a dated angiosperm supertree showed that myrmecochory has evolved in most of the major angiosperm lineages …

We suggest that the relatively low physiological and energetic costs of producing an elaiosome and the consistent selective benefits of myrmecochory (dispersal, protection from seed predators and fire, safe and nutrient-rich microsites) explain the numerous evolutionary and developmental origins of myrmecochory in angiosperm plants, and we propose that elaiosomes thus provide one of the most dramatic examples of convergent evolution in biology.

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