COS 123-6 - CANCELLED - Listening for love: investigating the impact of multimodal acoustic signals on female choice in the Australian black field cricket (Teleogryllus commodus).

Background/Question/Methods

Sensory adaptations, including hearing capabilities, have evolved in response to predation risk and opportunities for successful reproductive encounters. There is a scientific bias toward investigating sounds that fall within the range of human hearing (‘sonic’ signals); however, many insect species including members of the Gryllid family detect ultrasonic sounds used by aerial predators and vibrational sounds used by terrestrial predators, in addition to sonic signals used in conspecific reproductive advertisement. Multimodal hearing capabilities evolved in the context of preindustrial soundscapes that are shifting in the Anthropocene, and species that rely on sound in the current epoch may now be threatened by anthropogenic noise. The aim of this research is to use a model invertebrate system to understand how female reproductive choice is influenced by multimodal ambient noise masking relevant acoustic signals. Controlled laboratory playback trials were conducted to test the behavioral response of Australian black field crickets (Teleogryllus commodus) across multimodal noise treatments and sound intensities. Three noise treatments (airborne sonic 1-20 kHz, airborne ultrasonic 25-45 kHz, and substrate-borne vibrations 100-1,000 Hz) were overlayed with the acoustic playback of male signals to test the female’s ability to discriminate between a high and low-quality male signals in variable sound conditions.

Results/Conclusions

In the presence of sonic noise, the likelihood of a females approaching a high-quality male signal decreased at the low (z= -2.30, p= 0.02) and high (z= -2.86, p= 0.004) intensities. In the presence of ultrasonic noise, the likelihood of approaching the high-quality male signal decreased at all intensities (70 dB: z=-2.48, p= 0.01; 75 dB: z=-1.95, p= 0.05, 80 dB: z= -3.19, p=0.001). The likelihood of approaching the high-quality male signal also decreased in the presence of substrate-borne vibrations across all of intensities (1 mm/s: z= -3.43, p< 0.001; 5 mm/s: z= -2.170, p= 0.03; 15 mm/s: z=-3.62, p< 0.001). Noise, regardless of modality and intensity, influenced a female’s ability to discriminate between a low-quality and high-quality male signal. Animals rely on multiple modalities of sound to extract meaningful information, by only focusing on one modality, we are unable to fully understand the impact of anthropogenic noise on animal behavior. This study will expand our knowledge of the effects of anthropogenic noise in a model taxa and highlight why we need to consider the animal’s sensory system sensitivity when studying noise.