Interactions between ants and non-myrmecochorous diaspores in a tropical wet forest in southern Bahia, Brazil

Abstract

Abstract:Interactions between ants and non-myrmecochorous diaspores occur frequently on the forest floor and the results of these interactions (e.g. diaspore cleaning or removal) will often depend on the morpho-chemical characteristics of the diaspores. We conducted two different experiments with seven plant species in the north-eastern Atlantic forest, Brazil. To evaluate whether ant interactions decrease diaspore persistence time on the forest floor, we established sample stations by placing five diaspores of each species spaced every 10 m along a transect and monitored ant interactions over a 24-h period. We also compared diaspore removal by ants and vertebrates through a paired experiment. We monitored removal of the seven plant species in treatments where ants were excluded and treatments where vertebrates were excluded. We recorded 332 ant–diaspore interactions, most resulting in ants cleaning diaspores in situ. Persistence of diaspores on the forest floor varied greatly among studied species and was less than 50% for three species. Ants also removed more diaspores than did vertebrates. Number of diaspores removed by ants was greater for small diaspores and with high lipid concentration. Ant–diaspore interactions may not always exert a positive influence on plant recruitment for diaspores with poor nutrient concentration. Consequently, ants may play a disproportionately important role as secondary dispersers in tropical forests.

Natural History of Ants: What We (do not) Know About Trophic and Temporal Niches of Neotropical Species

“…It was a comparatively frequent species (Table 2), but appeared always in low numbers and was not collected in pitfalls. This result differs from the widespread use of fleshy diaspores found in Santana et al (2013), and also from the use of baits in Orivel et al (2009). The latter authors suggested that abiotic factors play a role in the ecological shift of W. auropunctata from open to forest areas.…”

“…In Atlantic forest, ca. 1400 km north of the present study site, Santana et al (2013) qualitatively showed it interacting with seven nonmyrmecophorous diaspores on the ground.…”

As formigas poneromorfas do Brasil

“…de formigas são os principais agentes de remoção de frutos e sementes pequenos (até 1 g) caídos ao solo em diferentes vegetações no Brasil (LEAL; OLI-VEIRA, 1998;OLIVEIRA, , 2003CHRISTIANINI et al, 2007;LIMA et al, 2013;ZWIENER et al, 2012;SANTANA et al, 2013;BIEBER et al, 2014). Observações em colônias cativas de poneromorfas indicam que estas formigas comportam-se como dispersoras de sementes, descartando intacta a maioria das sementes nas lixeiras dos ninhos após a remoção da polpa OLIVEIRA, 2001).…”

“…CHRISTIANI-NI et al, 2007), ou rearranjar a distribuição das sementes no solo em fezes e regurgitos de vertebrados (PASSOS; . Como a remoção é rápida -em geral nas primeiras 24 hs da semente chegar ao solo (PIZO; CHRISTIANINI et al, 2007;SANTANA et al 2013), as formigas dispersoras diminuem a exposição das sementes a animais granívoros, como roedores (GILADI, 2006). Além disso, ao redistribuir as sementes caídas, estas formigas as transportam para seus ninhos.…”

“…Poneromorfas tipicamente são formigas que proporcionam uma dispersão de alta qualidade para as plantas, e como tal sua atração por diásporos ricos em lipídeos pode favorecer plantas que produzam diásporos pequenos (até 1 g) com estas características (CHRISTIANINI et al, 2012;SANTANA et al, 2013, LEAL at el., 2014b. Até que ponto as plantas ao longo da evolução foram selecionadas para atrair formigas que provêm uma dispersão de alta qualidade entre as muitas espécies na comunidade ainda é motivo de debate (partner choice, GILADI, 2006).…”