Phoretic Behaviour of Bromeliad Annelids (Dero) and Ostracods (Elpidium) using Frogs and Lizards as Dispersal Vectors

The phoretic behaviour of ostracods (Elpidium bromeliarum) andannelids (Dero superterrenus) that inhabit tank bromeliads was studied. Our previous field observations had shown that bromeliad ostracods can be found attached to the skin of amphibians and reptiles that move among bromeliads, probably allowing the ostracods to colonise new tanks. In this paper, we present the first record of bromeliad annelids found attached to frogs moving among bromeliads in the field. We have also enlarged the database on bromeliad ostracods engaged in phoretic association with terrestrial vertebrates in three locations in southeastern Brazil. In our laboratory experiments bromeliad annelids show a strong significant tendency to climb onto papers that had been in contact with frog skin when compared with control papers, indicating a kind of chemically oriented behaviour. Bromeliad ostracods, on the other hand, attached themselves to treated and untreated papers with same frequency. When brought into contact with various species of frogs and lizards, the bromeliad annelids and ostracods both presented preference to attach themselves to frogs, but the annelids showed a stronger preference to attach to frogs and to avoid attachment to lizards. Another experiment demonstrated that bromeliad annelids are much more prone to dehydration than are ostracods. We suggest that the chemically oriented behaviour presented by bromeliad annelids toward frogs could diminish the risk of death by dehydration during the transport among bromeliads due to the moist characteristic of frog skins.