MADS-box evolution in green algae

Research by Peter Narins et al. suggests that the neural processes that come into play when humans are ‘‘tricked’’ by ventriloquists may also elucidate the neural processes of aggressive behavior in amphibians. Cross-modal spatial integration in the brain ‘‘binds’’ separate auditory and visual cues over a limited temporospatial range, and such integration is involved in the processing of sound from one source that seems to emanate from another. Narins et al. explored these mechanisms in males of the dart-poison frog, Epipedobates femoralis, which defend their territory in response to visual and auditory cues of intruders. The researchers used an electromechanical frog emanating an auditory cue (natural call from a loudspeaker) and a visual cue (vocal-sac inflations and deflations) to trigger aggressive territory-defending behavior in the frogs. In one set of experiments, a time delay of up to 8.7 s was used between the visual and auditory cues, and in a second set, the visual and auditory cues were put out at the same time but at different locations between 12 and 50 cm. Despite the temporal and spatial disparities, in both instances aggressive behavior was observed when there was at least some temporal overlap of the stimuli. The authors also found that a range of temporal and spatial disparities exists for which aggressive behavior persists. According to the researchers, these results demonstrate that temporal and spatial integration may be reliably estimated in a freely behaving animal in its natural habitat, and aggressive behavior in this species may be used as an index of cross-modal integration. ‘‘Cross-modal integration in a dart-poison frog’’ by Peter M. Narins, Daniela S. Grabul, Kiran K. Soma, Philippe Gaucher, and Walter Hödl (see pages 2425–2429)