1 3 Oecologia (2014) 174:493–500 DOI 10.1007/s00442-013-2789-2 PLANT-MICROBE-ANIMAL INTERACTIONS - ORIGINAL RESEARCH Myrmecochores can target high-quality disperser ants: variation in elaiosome traits and ant preferences for myrmecochorous Euphorbiaceae in Brazilian Caatinga Laura Carolina Leal · Mário Correia Lima Neto · Antônio Fernando Morais de Oliveira · Alan N. Andersen · Inara R. Leal Received: 25 February 2013 / Accepted: 16 September 2013 / Published online: 2 October 2013 © Springer-Verlag Berlin Heidelberg 2013 Camponotus) were identified as those that rapidly collected and transported diaspores to their nests, often over substan- tial distances, whereas low-quality disperser ants (primar- ily species of Pheidole and Solenopsis) typically fed on elaiosomes in situ, and only ever transported diaspores very short distances. Low-quality disperser ants were equally attracted to the elaiosomes of all study species. However, high-quality dispersers showed a strong preference for diaspores with the highest elaiosome mass (and especially proportional mass). As far as we are aware, this is the first study to identify a mechanism of diaspore selection by high-quality ant dispersers based on elaiosome traits under field conditions. Our findings suggest that myrmecochorous plants can preferentially target high-quality seed-disperser ants through the evolution of particular elaiosome traits. Keywords Elaiosome-bearing seeds · Myrmecochory · Seed-removal experiments · Fatty acids · Oleic acid Introduction Animal-mediated seed dispersal is typically a diffuse inter- action compared with other plant-animal mutualisms such as pollination, as the transport of seeds can usually be accomplished by a range of generalist frugivores (Wheel- wright and Orians 1982; Blüthgen et al. 2007). Myrmeco- chory (seed dispersal by ants) is considered a particularly diffuse mutualism because a wide variety of generalist ant species remove and transport the seeds of a wide variety of myrmecochorous plants (Andersen 1988; Bronstein 1994; Rudgers and Strauss 2004). However, although many ant species are attracted to elaiosomes—the lipid-rich append- ages that make myrmecochorous seeds attractive to ants (Beattie 1983)—the dispersal service provided by them Abstract Recent evidence suggests that the traditional view of myrmecochory as a highly diffuse interaction between diaspores and a wide range of ant species attracted to their elaiosomes may not be correct. The effectiveness of dispersal varies markedly among ant species, and com- bined with differential attractiveness of diaspores due to elaiosome size and composition, this raises the potential for myrmecochorous plants to target ant species that offer the highest quality dispersal services. We ask the question: Do particular physical and chemical traits of elaiosomes result in disproportionate removal of Euphorbiaceae dia- spores by high-quality disperser ants in Caatinga vegetation of north-eastern Brazil? We offered seeds of five euphorb species that varied in morphological and chemical traits of elaiosomes to seed-dispersing ants. High-quality seed- disperser ants (species of Dinoponera, Ectatomma and Communicated by Diethart Matthies. L. C. Leal Programa de Pós-Graduação em Biologia Vegetal, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego s/n, Cidade Universitária, Recife, PE 50670-901, Brazil M. C. L. Neto Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Pernambuco, Rua Prof. Artur de Sá, s/n, Cidade Universitária, Recife, PE 50740-520, Brazil A. F. M. de Oliveira · I. R. Leal (*) Departamento de Botânica, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego s/n, Cidade Universitária, Recife, PE 50670-901, Brazil e-mail: irleal@ufpe.br A. N. Andersen CSIRO Ecosystem Sciences, Tropical Ecosystems Research Centre, PMB 44, Winnellie, NT 0822, Australia