Anthropogenic noise can decrease tomato reproductive success by hindering bumblebee-mediated pollination

Abstract

Anthropogenic noise is a little-studied type of pollution that negatively affects the physiology, nervous function and development of insects, thereby it has the potential to disrupt even key ecological services such as pollination. Here, we investigate the effects of anthropogenic noise on the pollination success of the Bombus terrestris on tomatoes in controlled conditions. We expect that bumblebees avoid flowers exposed to noise more than flowers in non-noisy environments, leading to less efficient pollination and lower fruit quality. The experiment was conducted in Hungary, in 2023. Three treatments were applied to randomly chosen flowers: noisy (with played traffic noise); and two non-noisy, one allowing bumblebees and one excluding them. The flowers were enclosed with nets before maturity to avoid pollination, opened exclusively during treatment, and re-enclosed for three more days post-treatment. We recorded the marketing value of the fruits and the number of seeds they produced. We found no significant differences in the marketing value of fruits among treatments, but the number of seeds differed significantly suggesting that anthropogenic noise has a substantial effects on bumblebee-mediated pollination. Although these effects may be mitigated by habituation, loud external noise of various machines (e.g. irrigation systems) within polytunnels is still likely to contribute to the everyday noise exposure of bumblebees and could thus potentially lead to hidden economic losses in production. Therefore, further research is needed to understand the behavioural effects of both direct and indirect noise pollution on bumblebees.