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Simple Summary: The moth Loxostege sticticalis (Lepidoptera: Pyralidae) is a typical migrant insect pest found in North America, Eastern Europe, and Asia. The natural pheromone compounds of adult moths are involved in courtship and mating behavior. In this article, we examine the peripheral mechanisms of sex communication, demonstrating that the pheromone receptor (PR) LstiPR2 responds specifically to the major sex pheromone compound E11-14:OAc, which results in the activation of the "a" neuron in sensilla trichodea. The other four LstiPRs showed no response to any sex pheromone compounds. This study will contribute to a new, environmentally friendly strategy for integrated pest management of L. sticticalis. Lepidopteran insects mainly rely on sex pheromones to complete sexual communications. Pheromone receptors (PRs) are expressed on the olfactory receptor neurons (ORNs) of the sensilla trichodea and play an essential role in sexual communication. Despite extensive investigations into the mechanisms of peripheral recognition of sex pheromones in Lepidoptera, knowledge about these mechanisms in L. sticticalis remains limited. In this study, five candidate LstiPRs were analyzed in a phylogenetic tree with those of other Lepidopteran insects. Electroantennography (EAG) assays showed that the major sex pheromone component E11-14:OAc elicited a stronger antennal response than other compounds in male moths. Moreover, two types of neurons in sensilla trichodea were classified by single sensillum recordings, of which the "a" neuron specifically responded to E11-14:OAc. Five candidate PRs were functionally assayed by the heterologous expression system of Xenopus oocytes, and LstiPR2 responded to the major sex pheromone E11-14:OAc. Our findings suggest that LstiPR2 is a PR sensitive to L. sticticalis's major sex pheromone compound, E11-14:OAc. Furthermore, this study offers valuable insights into the sexual communication behavior of L. sticticalis, forming a foundation for further analysis of the species' central nervous system. [ABSTRACT FROM AUTHOR]

Therioaphis trifolii (Monell) is a well‐known pest in alfalfa cultivation in China. Individuals of T. trifolii were allowed to feed on 10 alfalfa cultivars and their growth, reproduction, and population life table parameters were estimated. Nymphs that fed on Hunter River had the longest development time, whereas nymphs that fed on Defu had the shortest development time. Adults that fed on Debao, Zhongmu No. 2, and Defu had the shortest development time, whereas adults that fed on Golden Empress and Hunter River had the longest development times. Individuals that fed on Zhungeer produced the greatest number of offspring (13.950), and those that fed on Hunter River produced the fewest offspring (6.000). The survival rate of T. trifolii was the highest on Algonquin and lowest on Hunter River, whereas the survival time was the longest on Golden Empress and shortest on Debao. The population that fed on Algonquin had the highest intrinsic growth rate (0.560) and shortest population doubling time (1.237 days), whereas those that fed on Hunter River had the lowest intrinsic growth rate (0.217) and longest population doubling time (3.194 days). The life table parameters of the experimental T. trifolii population were used to quantify the resistance strengths of the cultivars. Results indicate that the Hunter River cultivar may effectively resist damage from T. trifolii. This study provides a theoretical basis for breeding aphid‐resistant alfalfa cultivars, enabling further research into the prevention and control of aphid infestation. [ABSTRACT FROM AUTHOR]