Species identity cues: possibilities for errors during vibrational communication on plant stems

The efficiency of communication depends on the ability of conspecifics to recognize and locate each other, and the environment can impose important limitations on reliability of transmitted and received information. In contrast to the 3D space of airborne sound communication, substrate-borne vibrational signals are often transmitted via 1D plant stems and leaf stalks. In such situations, discrimination between signals emitted from several sources positioned on the same side of a receiver may be difficult, as the receiver may perceive this compound signal as emanating from a single source. Here, we examined the consequences of interactions between conspecific vibrational signals emitted from 2 sources for recognition of species-specific temporal patterns. In a 1D environment on a bean plant, males of the southern green stink bug Nezara viridula perceived conspecific female song emitted in alternation from 2 sources as a compound song with a signal repetition time outside the species-specific value and male responsiveness and the number of males locating a source (conspecific female) were low. By contrast, when the conspecific song was presented together with female signals of another stinkbug Acrosternum hilare, searching activity was not significantly affected. However, when conspecific and heterospecific signals were overlapping, males made significant orientation errors and the majority located the heterospecific source. Because both outcomes, missing a conspecific female and selecting a heterospecific partner, may ultimately lead to a reduced reproductive success, the results suggest that the 1D environment encountered on plant stems and branches imposes important limitations on vibrational communication system. Copyright 2011, Oxford University Press.