 Secondary Seed Dispersal by Ants of Ricinus communis (Euphorbiaceae) in the Atlantic Forest in Southeastern Brazil: Influence on Seed Germination by Valéria Forni Martins 1 , Paulo Roberto Guimarães Jr. 1,2 , Rogério Rosa da Silva 3 & João Semir 4 ABSTRACT Some seeds rely on fleshy lipid-rich appendages as attractants to ants. By carrying those seeds to their nest, ants play a major role as seed dispersers and can provide suitable conditions for seed germination. Ricinus communis (the commonly known castor) seeds are primarily dispersed by autocory but probably present secondary dispersal by ants, once they bear a lipid-rich elaiosome. e following questions were addressed: (1) are ants legitimate dispersers of castor seeds?; (2) which ant species interact with the seeds?; and (3) is germination success higher in a predicted scenario met by seeds discarded from ant nest? We compared the removal of seeds with and without elaiosome and we determined which ant species interact with castor seeds and whether there was seed predation by ants. We performed experiments in controlled conditions to evaluate seed germination response to light, tem- perature and elaiosome. Seeds with elaiosome were removed preferentially and no predation was found, indicating that ants are legitimate seed dispers- ers. A large coterie of ants (20 species) interacts with castor seeds, especially Myrmicinae species. Elaiosome removal enhanced germination success, as well as alternated temperatures and absence of light. erefore, by discarding seeds without elaiosome on the pile mound, ants may submit castor seeds to conditions that enhance germination. Keywords: ant nest, castor, elaiosome, forest edge, myrmecochory, light, temperature. 1 Programa de Pós-Graduação em Ecologia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, BRAZIL. E-mails: vfm@unicamp.br , paulomiudo@uol.com.br. 2 Integrative Ecology Group, Estación Biológica de Doñana, CSIC, Sevilla, SPAIN. 3 Museu de Zoologia da Universidade de São Paulo, São Paulo, BRAZIL. E-mail: rogeriorosas@gmail.com. 4 Departamento de Botânica, Instituto de Biologia, Universidade Estadual de Campinas, C.P. 6109, 13083-970, Campinas, SP, BRAZIL. E-mail: semir@unicamp.br. our dictionary does not recognize these bolded words, are they spelled correctly?