Reproductive status influences multisensory integration responses in female round gobies, Neogobius melanostomus
Reproductive signalling often involves multimodal signals that are sent between conspecifics. While it is often easier to study one sensory modality at a time, examining multiple sensory modalities together may lead to a fuller understanding of how sensory signals are integrated under natural conditions. Often when integration occurs, behavioural responses are modified compared to those that occur in response to one sensory modality. We exposed female round gobies, Neogobius melanostomus, to a reproductive male's call and to extracts of water conditioned by a reproductive male (chemical stimulus) separately and simultaneously to examine differences between the females' unimodal and multimodal responses to male stimuli. We also tested females across the breeding season to examine effects of reproductive status on female responsiveness. Reproductive females were attracted to the unimodal stimuli, but when they were presented with multimodal stimuli, they spent significantly more time in the area of stimulus presentation than they did when they were presented with either stimulus alone. Nonreproductive females showed no enhancement of their response to multimodal stimulation and often failed to respond to any signals. Our results show that female gobies may cycle in their attraction and localization abilities to male stimuli throughout the breeding season and that reproductive females have a synergistic response to multimodal stimuli from reproductive males.