Distance Dependent Contribution of Ants to Pollination but Not Defense in a Dioecious, Ambophilous Gymnosperm

• DOI: 10.3389/fpls.2021.722405
• Publication Date: 2021-09-08T05:28:54Z
• Authors: Adriana Aranda-Ri...; Javier Torréns; Natalia I. Yela; María Magdalena B...; Verónica S. Di St...
• Keywords: Gymnosperm; Anemophily; Pollen source; Zoophily

Dioecious plants are obligate outcrossers with separate male and female individuals, which can result in decreased seed set increasing distance between the sexes. Wind pollination is a common correlate of dioecy, yet combined wind insect (ambophily) could be advantageous compensating for pollen flow to isolated females. Dioecious, ambophilous gymnosperms Ephedra (Gnetales) secrete drops (PDs) cones that capture airborne attract ants feed on them. Plant sugary secretions commonly reward exchange indirect plant defense against herbivores, more rarely pollination. We conducted field experiments investigate whether pollinators and/or defenders South American triandra , their contribution cone protection varies plants. quantified assessed effectiveness as by investigating relative set, visitation rate at from nearest male. Ants accounted most visits E. where they consumed PDs, load was larger bigger without reduction viability. While main contributor overall, dependent. Ant not significant shorter distances, farthest (23 m), 20 times less reached females, enhanced 30% compared depending solely found no evidence contribute preventing damage. Our results suggest that, despite short-range movements, offset limitation females wind-pollinated propose enhance reproductive success via targeted delivery pollen, through frequent contact ovule tips while consuming PDs. study constitutes first experimental quantification distance-dependent provides working hypothesis ambophily other dioecious lacking pollinator