Ant removal distance, but not seed manipulation and deposition site increases the establishment of a myrmecochorous plant
Myrmecochory (seed dispersal by ants) is a unique seed dispersal syndrome among invertebrates. It comprises three main phases: seed removal, seed manipulation, and seed deposition. However, the contribution of each phase to seed and seedling fate remains unclear. Here, we experimentally quantified the effects of each phase of myrmecochory on seed germination and seedling establishment, the two most critical life history stages involved in plant recruitment. We established 30 sample points, and each included an adult Mabea fistulifera tree, an Atta sexdens nest entrance, and six seed depots. We monitored the germination of M. fistulifera seeds for 3 months and subsequently followed the growth and mortality of the resulting seedlings for 12 months. Only the dispersal distance influenced plant establishment, reducing seed germination and increasing seedling growth, but with no effect of seed manipulation and deposition site. Despite the contrasting effects of distance on seed germination and seedling growth, the positive effect of dispersal distance on seedling growth was ten times greater than the negative effect on seed germination. Moreover, A. sexdens behaved neither as granivore nor as herbivore of M. fistulifera seeds or seedlings, which suggests that seed dispersal by A. sexdens is advantageous to M. fistulifera. Thus, the joint occurrence of these two species in disturbed areas could have a positive effect on this pioneer plant population, which might promote forest regeneration.
KeywordsSeed-seedling conflict Direct dispersal Zoochory Leaf-cutting ant Insect-plant interaction
This article was part of TVF's master thesis that was funded by the Fundação de Amparo a Pesquisa de Minas Gerais (FAPEMIG) and by the Programa de Pós-graduação em Ecologia from the Universidade Federal de Viçosa (UFV), and LNP was supported by a Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (PNPD/CAPES) grant. We are grateful for financial support from Pesquisa & Desenvolvimento of Agência Nacional de Energia Elétrica and Companhia Energética de Minas Gerais (P&D ANEEL/CEMIG, PROECOS project GT-599), FAPEMIG (APQ-01424-15) and CNPq (428298/2018-4) research project grants. We are also grateful to O.L. Fernandes, R. Silva Dos Santos, M. M. Maia, and V. C. Rocha for help with fieldwork, to the Departamento de Engenharia Florestal (UFV) for allowing access to the study site, to Della Lucia’s laboratory for lending us their ant colonies, to Tatiana Cornelissen and Paulo Peixoto for help with statistical analysis, to Alexander Christianini for some good advices on the experimental design and finally to two anonymous reviewers for their helpful comments.
Author contribution statement
TVF, RRCS, and RIC conceived and designed the experiments. TVF performed the experiments. TVF, RRCS, and RIC analysed the data. All other authors contributed substantially to writing the manuscript and provided editorial advice.
Compliance with ethical standards
Conflict of interest
All authors declare they have made a crucial scientific contribution to the study and that they have no conflict of interest. The authors also confirm that all parts of this work comply with the current research laws of Brazil.
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