Navigation in an odorant-landscape: mate finding and mate choice in a nocturnal moth

In moths, mate-searching males follow the species-specific pheromone, emitted by conspecific females. Research on odor-mediated mating in moths has traditionally focused on the odor as a means for mate recognition, rather than for the male mate preference. By using synthetic blends, rather than female moths, the studies have overlooked the influence of the female “quality” on male behavior. Here we tested the performance of male moths under different conditions of odorant-landscape in the context of mate-finding and mate assessment. The properties of the odorant-landscape were determined by the combination of two factors: (i) the number of available sources (single or two), and (ii) the relative quality of the source (higher or lower). Flights of males, presented with pheromones of females with high and low reproductive potential, were recorded using 3D cameras, in no-choice and choice arenas. The results inferred that: (1) The pheromone-mediated mating system in moths incorporates information used for mate-finding and mate-assessment. (2) A strong selective pressure operates on male moths during mate finding. (3) A possible source-detection mechanism, by which female quality influences the likelihood of a successful mate-finding. (4) Male’s adaptive preference for females in relation to their reproductive potential. (5) The available pheromone sources and their relative quality have a combined effect on the navigational behavior of flying male moths during mate finding. To our knowledge, this is the first documented evidence that links mate finding and mate choice, with in-flight performance, using a comprehensive ethological approach in nocturnal moths.