Physical and biological effects on moths' navigation performance.

In a chemosensing system, the local olfactory environment experienced by a foraging organism is defined as an odorscape. Using the nocturnal pink bollworm moth (Pectinophora gossypiella), we tested the combined effect of three biophysical aspects in its immediate odorscape to shed light on the coupling effects of biotic and abiotic factors on navigation performances of a nocturnal forager: i) the quality of the pheromone source, ii) the pheromone availability, and iii) the airflow characteristics. The navigation performance of the males was investigated using a wind tunnel assay equipped with 3D infrared high-speed cameras. The navigation performance of the males was analyzed using ethological and biomechanical parameters.The results of this work indicate that: (1) the biophysical factors have combined effects on the navigation performance of mate-searching males; (2) Natural and sexual selection play an important role in shaping the pheromone-mediated sensory performance of nocturnal male moths; herein, the role of natural selection overrides that of sexual selection; (3) During odor-mediated mate-finding navigation, the male moth applies a tradeoff decision-making process based on weighted information from the biological and physical characteristics of the odorscape. This decision-making process includes weighting the tradeoff between the cost involved in flying under different flow conditions, the availability of different odor sources, and their quality.