Multimodal signal-mediated sexual communication in parasitoids: perception, mechanism and behaviour.

Parasitoids mate ritualistically and rely on a combination of sensory cues to navigate sexual communication, with olfactory signals playing central roles. This review examines the ritualistic communication involved in parasitoid mating, beginning with how conspecifics detect their counterparts through chemical cues, particularly pheromones until the mate marking behaviour by males. Therefore, we aim to explore the sequential and synergistic involvement of chemical, acoustic, vibrational, visual and tactile cues in the sexual communication of parasitoids. For example, once females or males are located based on long-distance pheromonal and acoustic communication, courtship is followed by the involvement of acoustic, vibrational, contact compounds and visual signals at close-range, whereby females or males evaluate the counterpart for mate choices. The interaction between different cues during courtship and mating is examined, highlighting how they influence reproductive behaviours and success. Post-mating interactions are also discussed, focusing on how communication may continue to ensure maintenance of female reproductive strategies. This review addresses the emerging field of sexual cue perception in parasitoids, emphasizing that while initial studies have only recently begun to explore underlying mechanisms, there remains a profound lack of understanding of how parasitoid nervous systems integrate multiple sensory inputs. Emphasizing the roles of multimodal signal-mediated sexual communication in parasitoids, this review sheds light on their integrated use and suggests implications for pest management and future research directions.