Abstract
Spodoptera exigua and S. litura are two sympatric species in China and many other countries. Both moths employ a multiple component sex pheromone blend, including a common component Z9,E12-14:OAc, and two specific components Z9-14:OH and Z11-16:OAc for S. exigua, and one specific component Z9,E11-14:OAc for S. litura. For the two species, it has been well documented that males are able to recognize and behaviorally attracted by their species-specific sex pheromone, which functions as a means of reproductive isolation, but whether males could mutually recognize pheromone components of its sympatric species is unknown. In the present study, the electroantennogram (EAG) and field evaluation were conducted to address this topic. The EAG recordings revealed that males of each species could significantly respond to specific components of its sympatric species, although the response values were lower than that to its own major component. In field tests, the specific components Z9-14:OH and Z11-16:OAc of S. exigua strongly inhibited the male catches of S. litura to its conspecific sex pheromone, while specific component Z9,E11-14:OAc of S. litura significantly reduced the male catches of S. exigua to its sex pheromone. Furthermore, the combined lure of the two species completely inhibited male catches of S. litura, and significantly decreased the male catches of S. exigua, compared to the species-specific lure alone. The results demonstrated that males of the two sibling species could perceive the specific components of its counterpart, suggesting that mutual recognition of pheromone components may function to strengthen the behavioral isolation between the two species. Our study has added new knowledge to the reproductive isolation via sex pheromone communication system in sympatric moth species, and provided a base for designing of mating disruption tactics targeting multispecies by using insect sex pheromones.
Highlights
Lepidoptera is the second largest insect group, including about 150,000 species in the world
In order to make sure whether the males of S. exigua or S. litura could response to the specific pheromone component of its sympatric species, the species-specific components were singly tested
At the higher doses of 100 and 1000 ng, the responses stimulated by Z914:OH and Z11-16:OAc were weaker than Z9,E11-14:OAc, the major pheromone component of S. litura
Summary
Lepidoptera is the second largest insect group, including about 150,000 species in the world. Some relative species that share same components, the differences in ratio of the components could be largely responsible for reproductive isolation, such as the case of Helicoverpa armigera and H. assulta. These two sibling species share the same two sex pheromone components of Z9-16:Ald and Z11-16:Ald, but in opposite ratios (Piccardi et al, 1977; Nesbitt et al, 1980; Kehat and Dunkelblum, 1990; Sugie et al, 1991; Li et al, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
