AntAttendance in Extrafloral NectarBearing Plant

Authors: Akira Yamawo Makoto Tokuda Noboru Katayama Tetsukazu Yahara Jun Tagawa

Publish Date: 2015/02/15

Volume: 42, Issue: 2, Pages: 191-198

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Abstract

In addition to direct defenses some plant species provide extrafloral nectar EFnectar and/or food bodies lipidrich particles to attract ants for their own indirect defenses To ascertain why such plants use indirect defenses we investigated the respective costs of direct and indirect defenses of Mallotus japonicus seedlings grown with and without ants present Mallotus japonicus plants growing with ants present antpresent secreted larger volumes of EFnectar containing greater amounts of sugars as an indirect defense trait These plants also showed chemical defensive traits such as the number of pellucid dots and the amount of accumulated phenolics to a lesser degree than plants without ants antabsent did Moreover the antpresent plants grew faster The estimated amounts of EFnectar sugars and food bodies were small compared to the amount of phenolics Plant biomass was correlated negatively with pellucid dot density and phenolic concentration Plant height was correlated negatively with phenolic concentration Moreover leaf biomass was correlated negatively with trichome density Taken together these results suggest a tradeoff between the expression of direct defense traits and plant growth Mallotus japonicus achieves more rapid growth with ants present We propose that this occurs because these ants provide lowcost indirect defenses allowing plants to reallocate their energy from direct defenses to growth instead This mutual benefit apparently facilitates ant–plant defensive mutualism

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