image: Philidris nagasau and a Squamellaria huxleyana seedling in Fiji. view more
Credit: Image courtesy of Guillaume Chomicki.
A study examines how ants optimize plant cultivation. The ant Philidris nagasau is known to cultivate epiphytic plants of the genus Squamellaria, but the evolutionary tradeoffs in this relationship are unclear. Guillaume Chomicki and colleagues examined how P. nagasau cultivated Squamellaria species under varying growth conditions in Fiji between 2014 and 2019. The authors found that the ants obtained 7.5-fold more floral food from plants cultivated in full sun than from plants cultivated in full shade. Compared with plants cultivated in light conditions, plants cultivated in dark conditions contained more nitrogen, exhibited more damage from herbivores, and were fewer in number. Further, the ants more often performed crop-protection patrolling on plants growing in full sun than on plants growing in full shade. Despite nitrogen fertilization tradeoffs, the ants tended to cultivate crops in the sun because this condition provides the highest benefits to the ants due to the volume of food produced. Compared with sun-cultivated plants, shade-cultivated plants produce less food for the ants and consequently receive more nitrogen fertilizer input from the ants, because the ants prey on insects for additional protein to supplement their diet. Furthermore, ants may have evolved plant growth-optimizing behaviors millions of years before humans began farming, according to the authors.
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Article #19-19611: "Tradeoffs in the evolution of plant farming by ants," by Guillaume Chomicki, Gudrun Kadereit, Susanne S. Renner, and E. Toby Kiers.
MEDIA CONTACT: Guillaume Chomicki, Durham University, UNITED KINGDOM; tel: +44 (0) 191 33 41238; email: <guillaume.chomicki@gmail.com>
Journal
Proceedings of the National Academy of Sciences