Population Divergence in the Mate Choice of Tribolium castaneum and Its Association with Gut Bacteria

Abstract

To reveal population divergence in the mate choice and its mechanistic basis, the mating rhythm, mating preference and male volatile profiles of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae) were studied. During ten days after emergence, six geographical populations of T. castaneum exhibited an identical daily or circadian mating rhythm. Males showed significant attraction to females while females did not show attraction to males. Furthermore, male attraction to females varied significantly within six populations, while female preference to males did not. Males from the HBWH population were most attractive to females sequentially followed by males from the populations of SHJD, HNZZ, GA1, GDST, and ZJJX, which was positively correlated with their 4,8-dimethyldecanal (DMD) production. Gnotobiotic reinoculation of two gut bacteria, Citrobacter freundii and Escherichia coli, to axenic males significantly enhanced their attraction to females and DMD production. It could be concluded that: (i) in the mate choice of T. castaneum, males were more like the sexual pheromone senders and females were the pheromone receivers; (ii) there was detectable divergence in the chemical communication among six populations of T. castaneum, which could be mainly attributed to alterations in the male pheromone production rather than changes in the female pheromone perception; and (iii) gut bacteria could modulate the chemical communication of the host by interfering with the pheromone production. Such knowledge will provide insights into optimizing trapping technologies for pest management.