Optimization of a pheromone lure by analyzing the peripheral coding of sex pheromones of Spodoptera frugiperda in China

Abstract

BACKGOUND Sex pheromones of the fall armyworm, Spodoptera frugiperda, show differences in composition and proportions in different geographical populations, but always contain Z9‐14:OAc as the major component. Odorant receptor neurons (ORNs) housed in the long trichoid sensilla (TS) of male antennae are essential to detect female‐released sex pheromones in moths. RESULTS In this study, we identified seven components from pheromone gland extracts of female S. frugiperda in the Yunnan population from China, including (Z)‐7‐dodecen‐1‐yl acetate (Z7‐12:OAc), (Z)‐9‐tetradecenal (Z9‐14:Ald), (Z)‐9‐dodecen‐1‐yl acetate (Z9‐12:OAc), (Z)‐9‐tetradecen‐1‐yl acetate (Z9‐14:OAc), (E)‐11‐tetradecen‐1‐yl acetate (E11‐14:OAc), (Z)‐11‐tetradecen‐1‐yl acetate (Z11‐14:OAc) and (Z)‐11‐hexadecen‐1‐yl acetate (Z11‐16:OAc) at a ratio of 1.2:4:0.8:79.1:1.6:1.6:11.7 by gas chromatography coupled with mass spectrometry. Gas chromatography‐electroantennographic detection showed that Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc are the male antennal active components. Peripheral coding of pheromones in males was investigated by single sensillum recording. Five functional neurons housed in three types of TS were identified based on profiles of neuronal responses, which are responsible for attractive component Z9‐14:OAc, synergistic components Z7‐12:OAc, Z11‐16:OAc, interspecific pheromones (Z)‐9‐tetradecen‐1‐ol (Z9‐14:OH) and (Z,E)‐9,12‐tetradecadien‐1‐yl acetate (Z9,E12‐14:OAc), respectively. Wind tunnel and field tests demonstrated that a ternary combination of Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc at a ratio of 88:1:11 shows the strongest attractiveness to males. Conclusion An optimized pheromone blend of Z9‐14:OAc, Z7‐12:OAc and Z11‐16:OAc in an 88:1:11 ratio was identified for monitoring the invasive pest S. frugiperda in China. Five functional ORNs encoding intra‐ and interspecific pheromones were identified in male antennae, of which three neurons encode attractive component Z9‐14:OAc, synergistic components Z7‐12:OAc and Z11‐16:OAc, respectively, and the other two neurons encode interspecific pheromones Z9‐14:OH and Z9,E12‐14:OAc, separately. © 2022 Society of Chemical Industry.

Development of a New Sex Attractant via the Peripheral Coding of Pheromones in Mythimna loreyi

“…Z 9, E 11-14:OAc is the major pheromone component of S. litura and also is an antagonist against S. exigua . , This suggests that one species can recognize the sex pheromone components of other sympatric species, thereby maintaining reproductive isolation. In previous studies, Spodoptera frugiperda , a species from another genus, showed similar pheromone components compared with M. loreyi , which resulted in inaccurate population monitoring of S. frugiperda in different regions. ,− Therefore, this ORN could detect the pheromones of sympatric species, which will be a putative target to screen the repellents of nontarget moths and improve the specificity of sex attractants when used to monitor populations of migratory pests.…”

“…Study of the pheromone recognition mechanism of males during the mating behavior of moths is crucial for understanding the molecular basis of their sexual communication system. Many studies have assessed the peripheral coding of pheromones in different families using the single sensillum recording technique. − In this study, we constructed a schematic diagram of peripheral olfactory coding of pheromones in male M. loreyi (Figure ) and characterized the response profiles of five ORNs housed in four functional types of trichoid sensilla to a panel of pheromones and their analogues. Combined with the reidentification of female pheromone components, we found that components Z 9-14:OAc, Z 7-12:OAc, Z 11-16:OAc, Z 5-14:OAc, E 11-14:OAc, and 14:OAc were able to activate the olfactory receptor neurons of male antennae.…”

“…Single sensillum recording (SSR) was performed to investigate the peripheral neuronal coding of pheromone components and analogues in male M. loreyi according to the standard protocol. , In male moths, pheromones are usually detected by trichoid sensilla, , so we recorded the responses of ORNs housed in trichoid sensilla located in the different flagella of antennae to pheromones under a Leica microscope (Z16 APO) at high magnification (920× ). Reference and recording electrodes were tungsten microelectrodes, sharpened by a 40% KNO 2 solution.…”

“…Moths finally display sexual behavior after integrating the input signals in the brain . As a primary unit of pheromone recognition, ORNs in trichoid sensilla have been functionally characterized in many families of male moths using the electrophysiology technique single sensillum recordings (SSR), including Noctuidae, − Bombycidae, Sphingidae, , Tortricidae, Crambidae, , Geometridae, and Carposinidae . Studies on the peripheral pheromone coding mechanism favor understanding the sexual communication system of moths, which also helps to screen the active components that are attractive to males and develop efficient behavior regulators.…”

A Social Network Analysis approach for identifying critical research areas in the management of Fall armyworm (Spodoptera frugiperda)

“…Improvements to the monitoring system have led to the creation of a particular mix of pheromones that can draw in fall armyworms. The pheromone components and the sensory neurons and pheromone receptors responsible for sex allocation have been identi ed (Wang et al, 2022;Zhong et al, 2022). Additionally, methods have been developed to increase the e ciency of producing Telenomus remus, a natural agent used to manage fall armyworms (W. , and cost-effective synthetic diets have been developed for the fall armyworm rearing process (Shishuai et al 2022).…”