Cerambycid beetles (Cerambycidae) are major forest pests, posing a serious threat to the security of forest resources worldwide. Extensive research has focused on the control of cerambycid beetles from physiological and biochemical perspectives. Despite the important roles of insect haemolymph in physiological processes, efficient collection methods for Cerambycidae are lacking. For the efficient and easy collection of large amounts of pure haemolymph from adult cerambycid beetles, a new method, named net centrifugation, was developed. Three species of cerambycid beetles with large differences in size, Anoplophora chinensis, Monochamus saltuarius and Saperda populnea, were selected for the study. Haemolymph was collected by the newly developed net centrifugation method—in which an inner nylon net is used during centrifugation under optimised conditions, and a relatively small wound is generated on the insect—as well as the traditional tearing method and double centrifugation method. Among the three methods evaluated, the net centrifugation method caused the least damage to cerambycid beetles during the whole operation. This method resulted in the most haemolymph from a single beetle, with the lowest turbidity, mostly pure haemocytes in the precipitate, the clearest haemolymph smears by microscopy and the highest quality of RNA extracted from haemocytes. The net centrifugation method has a high collection efficiency, providing important technical support for haemolymph extraction and entomological research.

Insects use a powerful and complex olfactory recognition system to sense odor molecules in the external environment to guide behavior. A large family of odorant receptors (ORs) mediates the detection of pheromone compounds. Anoplophora glabripennis is a destructive pest that harms broad-leaved tree species. Although olfactory sensation is an important factor affecting the information exchange of A. glabripennis, little is known about the key ORs involved. Here, we identified ninety-eight AglaORs in the Agla2.0 genome and found that the AglaOR gene family had expanded with structural and functional diversity. RT-qPCR was used to analyze the expression of AglaORs in sex tissues and in adults at different developmental stages. Twenty-three AglaORs with antennal-biased expression were identified. Among these, eleven were male-biased and two were female-biased and were more significantly expressed in the sexual maturation stage than in the post-mating stage, suggesting that these genes play a role in sexual communication. Relatively, two female-biased AglaORs were overexpressed in females seeking spawning grounds after mating, indicating that these genes might be involved in the recognition of host plant volatiles that may regulate the selection of spawning grounds. Our study provides a theoretical basis for further studies into the molecular mechanism of A. glabripennis olfaction.

Pheromones play an important role in mate choice in insects, and pheromone synthesis pathways are potential targets for the control of harmful insects, among which desaturation is of great significance in pheromone structural diversity. However, little is known about the desaturase genes regulating pheromone synthesis in Coleoptera. In this study, taking the internationally significant pest Anoplophora glabripennis as a research object, we identified 6 AglaFAD genes, all of which were mapped to the endoplasmic reticulum and shared a highly similar distribution of conserved domains. A phylogenetic analysis showed that AglaFAD1–2 and AglaFAD3–6 exerted desaturation at different positions of the acyl chain, respectively. In regard to the expression levels of these six AglaFADs in both sexes, six tissues and three developmental stages were analyzed by qPCR. Combined with the chemical composition of the female pheromones that have been identified, two candidate genes, AglaFAD2 and AglaFAD5, which are specifically expressed in females, were screened, showing higher expression levels before mating and significantly decreasing after mating. It is speculated that they may be involved in the biosynthesis of contact pheromones in females. These results provide a basis for detailed functional studies of candidate genes in insect pheromone synthesis.