Hearing Ability Decreases in Aging

16 Insects display signs of aging, despite their short lifespan. We focus on the aging of adult locusts and 17 their subsequent hearing ability. Our results indicate that younger adults (two weeks after maturity) 18 have a greater neurophysiological response to sound, especially for low frequencies (<10kHz), as well as 19 shorter latency to this neural response. Interestingly, when measuring displacement of the locust 20 tympanal membrane, which the receptor neurons are directly attached to, we found the movement is 21 not directly correlated with the neural response. Therefore we suggest the enhanced response is due to 22 the condition of their tissues (e.g., elasticity). Secondly, we found that females and males do not have 23 the same responses, particularly at four weeks post adult moult. We propose that this is due to female 24 reproductive condition reducing the ability to receive sounds. Our results indicate older animals may 25 therefore be less sensitive to the sounds of approaching predators. 26