RESUMEN
Most plants that inhabit ant-gardens (AGs) are cultivated by the ants. Some orchids occur in AGs; however, it is not known whether their seeds are dispersed by AG ants because most orchid seeds are tiny and dispersed by wind. We performed in situ seed removal experiments, in which we simultaneously provided Azteca gnava ants with seeds of three AG orchid species and three other AG epiphyte species (Bromeliaceae, Cactaceae and Gesneriaceae), as well as the non-AG orchid Catasetum integerrimum. The seeds most removed were those of the bromeliad Aechmea tillandsioides and the gesneriad Codonanthe uleana, while seeds of AG orchids Coryanthes picturata, Epidendrum flexuosum and Epidendrum pachyrachis were less removed. The non-AG orchid was not removed. Removal values were positively correlated with the frequency of the AG epiphytes in the AGs, and seeds of AG orchids were larger than those of non-AG orchids, which should favour myrmecochory. Our data show that Azt. gnava ants discriminate and preferentially remove seeds of the AG epiphytes. We report for the first time the removal of AG orchid seeds by AG ants in Neotropical AGs.
Asunto(s)
Hormigas/fisiología , Orchidaceae , Dispersión de Semillas , Semillas , Animales , Bromeliaceae , Cactaceae , Jardines , Orchidaceae/fisiología , SimbiosisRESUMEN
Prey signalling to predators is an attempt to divert or nullify an attack even before it occurs. If these signals are backed up by a potent defence, then the likelihood of the predators learning to avoid them is high. In species that use deceptive signalling, predators could learn to overcome such a display and diminish the efficacy of the display. We studied the effect of experience on the efficacy of tephritid fly displays against jumping spiders. We compared attacks on displaying flies, non-displaying flies, and two other prey species (a facile prey and a prey with a defence). Spiders were more likely to attack displaying flies over time. However, spiders that were familiar with the fly appearance but not display also increased their attack rates. We suggest that spiders attend to both components of the fly display, i.e. motion and appearance, but with motion cues taking priority.