Hosts must distinguish mutualistic symbionts from antagonists while avoiding harmful immune overactivation, yet the mechanisms maintaining this balance remain unclear. This challenge is acute during biological invasions, where exposure to novel microbial communities can outpace host genetic adaptation. Dendroctonus valens (RTB) associates with its mutualistic fungus Leptographium procerum (Lp), forming an invasive beetle-fungus complex during attacks on Chinese pines. Lp fails to trigger antimicrobial peptide expression but induces the heat shock protein 83 (HSP83). The native antagonist Ophiostoma minus (Om) activates immunity through pattern recognition receptors, including PGRP-SA, PGRP-SC2, βGRP3, and βGRP5. HSP83 modulates these responses through two-tiered negative regulation. First, it associates with PGRP-SA, βGRP3, and βGRP5 to attenuate Om detection. Second, it interacts with NF-κB-like factor Dorsal to limit antimicrobial peptide production. This symbiont-induced regulation enables selective defense, supporting RTB survival during combined Lp and Om exposure while limiting excessive Toll-dependent PRR/AMP activation and easing immune-metabolic trade-offs. These findings define a symbiont-assisted, mutation-independent mechanism of host adjustment during biological invasions, in which microbial partners provide immediate immune benefits and influence host success in novel environments.

BACKGROUND:Parasitoid wasps often face higher mortality when trying to paralyze resistant hosts, a challenge with important consequences for host adaptation and biological control management. This study explores the ability of Sclerodermus guani, an ectoparasitoid, to adapt plastically by examining how rearing on hosts with varying resistance levels affects parasitism success and behavior. RESULTS:Two distinct wasp lineages were established: a stressful lineage (referred to as Ma wasp), continuously reared on resistant, nonheat-shocked Monochamus alternatus (Ma) larvae, and a permissive lineage (referred to as MaHS wasp), derived from the Ma wasp and reared on less-resistant, heat-shocked Ma (MaHS) larvae. Host preference assays showed that Ma wasps consistently preferred Ma larvae, whereas MaHS wasps displayed a significantly reduced preference for Ma larvae, with a notable shift by the tenth generation. When exposed to both Ma and MaHS larvae, MaHS wasps exhibited lower mortality and a higher population growth index than Ma wasps, indicating differences in host resistance. After ten generations of continuous rearing, the fitness of MaHS wasps on Ma larvae was significantly lower than that of Ma wasps. Behavioral assays further demonstrated that Ma wasps were more efficient at locating new hosts than MaHS wasps. CONCLUSION:These findings highlight the role of host resistance in parasitoid adaptation and emphasize the importance of host selection in the mass rearing of biological control agents. This research offers valuable insights for optimizing rearing methods to enhance biocontrol effectiveness. © 2025 Society of Chemical Industry.

The morphology, number, and distribution of antennal sensilla differ between males and females, reflecting adaptations to sex-specific ecological roles and life histories. In this study, scanning electron microscopy was employed to examine the antennal structure and sensilla types of adult males and females of Sclerodermus guani Xiao et Wu 1983 (Hymenoptera: Bethylidae), with a focus on identifying morphological differences between the sexes. The results revealed that the antennae of both sexes are geniculate; however, female antennae are shorter and broader than those of males. Each antenna comprises 13 segments, including a scape (1 segment), a pedicel (1 segment), and a flagellum (11 segments). Eight distinct types of sensilla were identified on the antennae of both males and females, with notable sex-specific differences in sensilla types and subtypes. Trichoid sensilla subtype III was found exclusively in males, whereas long basiconic sensilla and basiconic sensilla subtype II were unique to females. More than 70% of the antennal sensilla in both sexes were olfactory in nature, highlighting their predominant role in chemical detection. The observed sexual dimorphism in the morphology and distribution of olfactory sensilla suggests functional specialization, potentially linked to host localization in females and mate location in males.

Parasitoid wasps and entomopathogens are often jointly employed in biological control practices. For parasitic wasps, choosing a suitable host is the key to ensure optimal survival for themselves and their offspring, and consequently for their effectiveness in biological control. However, the mechanisms of how parasitoids choose between healthy hosts and those infected with entomopathogenic fungi are still elusive. Here, we found that Scleroderma guani, an ectoparasitic wasp preferentially choose a healthy host, Monochamus alternatus, rather than hosts infected 4 days after by Beauveria bassiana. The volatile methyl cinnamate emitted from B. bassiana was found to play a key role in this host selection process. The corresponding odorant receptor SguaOR48 was identified from the genome of S. guani and visualized its co-expression with SguaORco in antennal sensillae. Furthermore, by knockdown SguaOR48 expression in vivo, we demonstrated that the repellent response of S. guani to methyl cinnamate was abolished. These findings suggest that S. guani can determine the status of a host based on odour and avoid parasitizing unfavourable hosts. Our study sheds valuable insights into the molecular mechanisms behind host selection and trade-offs by parasitic wasps, and may also provide an opportunity for synergistic and efficient use of dual biocontrol for pest management in general.

BACKGROUND:Hymenopterous parasitoids serve as important biocontrol agents, offering a unique opportunity to investigate transgenerational effects in host adaptation. The phenotype and experiences of maternal wasps can influence various traits in their offspring, potentially influencing host-switching dynamics. Here, the inherent host preferences were explored in two colonies of a parasitoid Scleroderma guani, reared on Monochamus alternatus and Saperda populnea beetles respectively. The inherent influence of rearing history and maternal wasp experience on host preference plasticity is further discussed. RESULTS:The Monochamus alternatus-reared colony maintained an inherent preference for Monochamus alternatus while the Saperda populnea-reared colony showed a neutral tendency. These inherent preferences drove inter-colony differences in host preference plasticity, constraining preference shifts toward the lower-quality host Saperda populnea. Subsequently, a host-exchange experiment spanning five generations revealed a fitness-dependent preference shift when Saperda populnea-reared wasps were reared on Monochamus alternatus: the transition to Monochamus alternatus (a higher-quality but more defensive host) was postponed until maternal wasps adapted to host resistance by the fourth generation. CONCLUSION:In this case, Scleroderma guani presented an adaptive host preference shift strategy in consideration of ancestral experiences and fitness, providing insights into how generalist wasps maintain selective host preferences. These findings also have practical implications for optimizing artificial breeding of Scleroderma guani to enhance its efficacy in biocontrol against Monochamus alternatus, the primary vector of pinewood nematode. © 2025 Society of Chemical Industry.

Parasitoid wasps face increased mortality when paralyzing resistant hosts, involving host adaptation and biocontrol. This study investigates the plasticity of host adaptation in the ectoparasitoid Sclerodermus guani by examining how long-term rearing on hosts of differing resistance influences parasitism performance. Two distinct wasp lineages were established: the stressful Ma lineage, continuously reared on the highly resistant Monochamus alternatus (Ma) larvae, and the susceptible Sp lineage, continuously reared on the non-resistant Saperda populnea (Sp) larvae. Host preference assays revealed that Ma wasps exhibited a significant preference for Ma larvae, while Sp wasps favored Sp larvae. Although Ma wasps experienced higher mortality and a lower population increase index when reared on Ma larvae compared to the performance of Sp wasps on Sp larvae, they demonstrated superior parasitism efficiency when tested against resistant hosts. Specifically, Ma wasps had significantly lower mortality rates and higher population increase index than Sp wasps when both were tested on Ma larvae. In dual-parasitism trails, where 1 Ma wasp and 1 Sp wasp were introduced to the same Ma larvae, and in group trails involving 3 wasps from each lineage on the novel, high-resistant host Aromia bungii, the Ma wasps outperformed Sp wasps in paralysis success. Behavioral assays further indicated that Ma wasps invested more time in accessing host resistance but were quicker in locating hosts compared to Sp wasps. This research provides valuable insights for improving the design of mass rearing strategies to maximize the effectiveness of biological control agents in integrated pest management programs.

Complex interspecific relationships between parasites and their insect hosts involve multiple factors and are affected by their ecological and evolutionary context. A parasitoid Sclerodermus guani (Hymenoptera: Bethylidae) and an entomopathogenic fungus Beauveria bassiana (Hypocreales: Cordycipitaceae) shared the same host in nature, Monochamus alternatus (Coleoptera: Cerambycidae). They often encountered the semi-enclosed microhabitat of the host larvae or pupae. We tested the survival and reproduction of the parasitoid’s parent and its offspring fitness under different concentrations of B. bassiana suspension. The results show that S. guani parent females carrying higher concentrations of the pathogen shorten the pre-reproductive time and regulate their own fertility and their offspring’s survival and development. This minimal model of the interspecific interactions contains three dimensionless parameters, vulnerability (θ), dilution ratio (δ), and PR, which were used to evaluate the mortality effect of the parasitoid S. guani on its host M. alternatus under the stress of the entomopathogenic fungus B. bassiana. We compared the infection and lethal effect of the fungus B. bassiana with different concentrations to the parasitoid S. guani and the host larvae M. alternatus. At higher concentrations of the pathogen, the parasitoid parent females shorten the pre-reproductive time and regulate their own fertility and their offspring’s survival and development. At moderate concentrations of the pathogen, however, the ability of the parasitoid to exploit the host is more flexible and efficient, possibly reflecting the potential interspecific interactions between the two parasites which were able to coexist and communicate with their hosts in ecological contexts (with a high overlap in time and space) and cause interspecific competition and intraguild predation.

Scleroderma guani is a generalist ectoparasitoid of wood-boring insects. The chemosensory genes expressed in its antennae play crucial roles in host-seeking. In the present study, we identified 14 OBP genes for the first time from the antennae transcriptomes and genomic data of S. guani. The expression profiles of 14 OBPs were tested by RT-qPCR, and the RT-qPCR results showed that SguaOBP2/5/6/11/12/13 were specifically highly expressed in the female antennae. Then we performed ligand binding assays to test the interactions between six selected SguaOBPs with host specific chemical compounds from M. alternatus and pines. The binding results indicated that SguaOBP12 had a higher binding affinity with longifolene, β-caryophyllene, α-pinene, β-pinene, myrcene, butylated hydroxytoluene, and 3-carene. SguaOBP11 had a high or medium binding affinity with them. Furthermore, both SguaOBP11 and SguaOBP12 had a medium binding affinity with the aggregation pheromone of Monochamus species, 2-undecyloxy-1-ethanol. Finally, by using molecular docking and RNAi, we further explored the molecular interactions and behavioral functions of SguaOBP11 and SguaOBP12 with these vital odor molecules. Our study contributes to the further understanding of chemical communications between S. guani and its host, and further exploration for its role as a more effective biological control agent.

Background Biological invasions are responsible for substantial environmental and economic losses. The red turpentine beetle (RTB), Dendroctonus valens LeConte, is an important invasive bark beetle from North America that has caused substantial tree mortality in China. The lack of a high-quality reference genome seriously limits deciphering the extent to which genetic adaptions resulted in a secondary pest becoming so destructive in its invaded area. Results Here, we present a 322.41 Mb chromosome-scale reference genome of RTB, of which 98% of assembled sequences are anchored onto fourteen linkage groups including the X chromosome with a N50 size of 24.36 Mb, which is significantly greater than other Coleoptera species. Repetitive sequences make up 45.22% of the genome, which is higher than four other Coleoptera species, i.e., Mountain pine beetle Dendroctonus ponderosae, red flour beetle Tribolium castaneum, blister beetle Hycleus cichorii, and Colorado potato beetle Leptinotarsa decemlineata. We identify rapidly expanded gene families and positively selected genes in RTB, which may be responsible for its rapid environmental adaptation. Population genetic structure of RTB was revealed by genome resequencing of geographic populations in native and invaded regions, suggesting substantial divergence of the North American population and illustrates the possible invasion and spread route in China. Selective sweep analysis highlighted the enhanced ability of Chinese populations in environmental adaptation. Conclusions Overall, our high-quality reference genome represents an important resource for genomics study of invasive bark beetles, which will facilitate the functional study and decipher mechanism underlying invasion success of RTB by integrating the Pinus tabuliformis genome.

Intrasexual selection occurs in male-male competition over access to females and usually results in the larger male winning. While much research has documented that size matters, little is known about how the larger male wins. Dendroctonus valens is an aggregating monogamous bark beetle in which males have large variation in body size and display intense competition over females. Behavioral observation showed two males fight each other within the gallery by pushing/shoving and stridulated more when two males encountered each other. Experiments using two different-sized males synchronously competing showed that larger males won 95% of contests. Reciprocal displacement experiments using muted and intact males of different or equal size were used to simulate male-male competition. Larger males displaced the smaller resident male in 90% of contests, while smaller males prevailed over larger residents in 6.7% of contests. With both males silenced, larger males displaced smaller males in 80% of contests, while smaller males prevailed in 8% of contests. Further experiments using equal-sized males showed aggressive sound-emitting males displaced muted males in 67% of contests, yet intact males displaced other intact males in only 37.5% of contests. Sound analysis showed sound pressure level is an honest signal of body size and males chose soft sounds over loud aggressive sounds in assays. Therefore, D. valens males have evolved dual behaviors, fighting and aggressive sounds associated with body size, to assess rivals to compete for a partner, gaining insights in male-male competition for this species and for other animals.

The role of risk in behavioural choices leading to cooperation in attacking a prey or a host has proven to be difficult to assess in most systems because risk is difficult to quantify. For parasitoid wasps, paralysing a host is a key step for successful parasitism and reproduction, but wasps risk death or injury because of host defences and may require group action, which provides a model system to decipher the mechanism driving cooperation. We explored scenarios where wasps behave as either cooperators or free-riding defectors by using the parasitoid Sclerodermus guani and its host Monochamus alternatus. First, when one or two wasps paralysed a single host, the mortality of both increased with increasing host size but was significantly lower when there were two wasps. Second, fitness analysis showed that whether a wasp was involved in paralysing a host did not affect the number of eggs laid. Finally, when two wasps paralysed single large hosts, higher mortality risks led to more cooperation, whereas lower risk led to more frequent free riding. Our study implies that risk is involved in mediating the level of cooperation and provides an experimental demonstration of risk-driven cooperation of parasitoids. (c) 2020 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

The behavioral strategies and mechanisms by which some insects maintain monogamous mating systems are not well understood. We investigated the mating system of the bark beetle Dendroctonus valens, and identified several contributing mechanisms. Field and laboratory observations suggest the adults commonly form permanent bonds during host colonization. Moreover, it showed mated females that remained paired with males produced more offspring than mated females that were alone in galleries. In bioassays, a second female commonly entered a gallery constructed by a prior female. Videos show she commonly reached the location of the first female, but they did not engage in actual fighting. Rather, the second female typically departs to form her own gallery. Acoustic signaling likewise does not appear to influence female‐female encounters, based on controlled muting experiments. Instead, the intruder appears to perceive the resident's presence by physical contact. Both acoustic signals and volatiles released by females during gallery constructing were shown to attract males. After a male joined a female in a gallery, the male‐produced aggressive sounds, which were shown by playback to deter other males from entering the gallery. Unlike female‐female interactions, resident males use their head and rear to push intruders out of galleries. Additionally, volatiles released by males during feeding repelled intruding males, discouraging them from entering the gallery. Males also construct plugs that block the entrance, which may prevent subsequent males and predators from entering the gallery. Thus, D. valens has evolved multifaceted mechanisms contributing to single pairings that confer benefits to both sexes.

[目的]球孢白僵菌Beauveria bassiana是一种被广泛用于害虫生物防治的生防菌.本研究探讨了孢悬液浓度和宿主体型大小对球孢白僵菌对松墨天牛Monochamus alternatus幼虫的致病力的影响,旨在为松墨天牛的生物防治提供科学基础.[方法]分别用0.5％吐温-80(CK)以及1×105,1×106,1 ×107,1×108和1×109孢子/mL的球孢白僵菌孢悬液接种松墨天牛4龄幼虫,统计接种后15 d内幼虫死亡率和染菌率.同时用最佳浓度(1×109孢子/mL)的球孢白僵菌孢悬液接种体型大小分别为100～ 150,200～220,300～320,400～420,500～ 520和600～ 650 mg/头的松墨天牛幼虫,测定接种后20d内幼虫的死亡率和染菌率.[结果]接种1×105～1×109孢子/mL的球孢白僵菌后,松墨天牛4龄幼虫起初活动自如,后在头部出现烧灼状伤并且体色逐渐变红,最后周身长满菌丝.不同浓度下,随球孢白僵菌孢子浓度升高,松墨天牛4龄幼虫校正死亡率和校正染菌率增加.接种1 ×106～1×109孢子/mL球孢白僵菌孢悬液15 d的松墨天牛4龄幼虫累计校正死亡率均可达到100％,1×10 7,1×108和1×109孢子/mL浓度下,松墨天牛达到100％校正死亡率所需时间最少.接种0 (CK),1×105,1×106,1×107,1×108和1×109孢子/mL球孢白僵菌孢悬液的松墨天牛4龄幼虫校正染菌率在第15天分别为0,20.00％,86.67％,90.00％,96.67％和100.00％,表现为白僵菌孢子浓度越高,染菌率越高.1×109孢子/mL的接种浓度下,松墨天牛幼虫个体越大,天牛幼虫死亡率和染菌率越高.表现在第20天时,体型大小为100～150,200～220,300～ 320,400～420,500～520和600～650 mg/头的幼虫的死亡率分别为76.67％,76.67％,66.67％,93.33％,100.00％和100.00％,染菌率分别为60.00％,63.33％,60.00％,86.67％,96.67％和100.00％.[结论]球孢白僵菌悬浮液浓度对松墨天牛幼虫的死亡和侵染有显著影响,表现为随孢子浓度的增加而增加;同时,松墨天牛幼虫个体越大,死亡率和染菌率越高.研究结果对开展利用球孢白僵菌防治松墨天牛具重要借鉴和指导意义.

华山松大小蠹Dendroctonus armandi Tsai et Li是危害我国华山松Pinus armandii的主要蛀干害虫.收集和测定华山松树皮和华山松大小蠹的挥发物,根据挥发物组分设计配制8种诱芯,采用漏斗诱捕器进行林间诱捕筛选试验;应用诱芯Ⅱ进行多点诱捕验证和有效诱捕距离试验.结果表明:诱捕期内,诱芯Ⅱ平均诱捕华山松大小蠹1070头/诱捕器,显著高于其它7种诱芯;单个诱捕器一天最多诱捕1652头.诱芯Ⅱ在3个地点的平均诱捕量差异不显著,分别为83,114,101头/诱捕器,诱捕效果不存在地理差异;距离林缘50 m处诱捕量为43.5头/诱捕器,为最佳有效诱捕距离.该华山松大小蠹高效引诱剂可为我国华山松大小蠹的治理提供新技术.

Male preference for mating with large females and its benefits on fitness have been shown in several animal taxa. However, the mechanisms underlying this preference are less well known. Dendroctonus valens, a primarily monogamous bark beetle whose females initiate tunnels beneath the bark of host trees, provides a useful system for testing how male mate choice is based on size. Field observations and laboratory experiments demonstrated that D. valens males preferentially entered tunnels containing large females, and that large females were more fecund than small females. Behavioural assays showed that males could discern tunnel size, and preferred larger artificially constructed tunnels in a two-choice assay. Males were also able to walk more quickly through larger diameter tunnels. Volatiles and chirping sounds associated with females were also analysed. Female body size was positively associated with the intensity of the female's chirp, but not with the quantity of pheromones released. Playback of this chirp showed males preferred female-produced sound to a silent control, and that males could discriminate between soft and loud sounds. Male D. valens appear to have evolved strategies of mate selection by relying on dual cues, tunnel size and acoustic signals, to obtain a large partner to increase fitness. (C) 2017 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.

[Aim] This study aims to evaluate the predatory capability of Tetrigus lewisi larvae to final instar larvae and pupae of the yellow mealworm,Tenebrio molitor and the Japanese pine sawyer,Monochamus alternatus by feeding experiment in the laboratory,so to find an effective bio-control agent for the management of the pine sawyer.[Methods] To confirm the occurrence of M.alternatus and T.lewisi,field survey was carried out in November 2014 at a forest of Mt.Maanshan,Changdong,Fuyang County of Zhejiang Province by cutting down the infested trees by M.alternatus larvae and counting the number of each species by dissecting galleries made by beetle larvae.T.lewisi larvae were brought back indoor,and fed with final instar larvae and pupae of T.molitor and M.alternatus,respectively,to estimate the predatory capability of T.lewisi larvae.[Results] In the field survey,we found both T.lewisi larvae and residual body of the Japanese pine sawyer in the galleries made by M.alternatus larvae.Totally,36 T.lewisi final instar larvae and 1 096 M.alternatus larvae were collected in the infested dead pine trees,with the population density of the former being about 3％ of the latter.Indoor predatory experiment showed that one T.lewisi larva preyed on 0.6 and 1.6 larvae of T.molitor and M.alternatus per day,respectively.The total average number of T.molitor larvae preyed in five consecutive days was 3.2 individuals,which was significantly lower than that of M.alternatus larvae preyed (8.0 individuals) (P ＜ 0.0001).Moreover,T.lewisi larva could prey on both pupa of T.molitor and M.alternatus.The average preyed number of T.molitor and M.alternatus pupae was 1.4 and 2.0 individuals per day,respectively.The total average number of T.molitor pupae preyed in four consecutive days was 5.6 individuals,which was significantly lower than that of M.alternatus pupae preyed (7.8 individuals) (P =0.028).Furthermore,regression analysis showed that the predation amount of T.lewisi was not correlated with its body size.[Conclusions] Field survey confirmed that T.lewisi is widely distributed in the galleries of M.alternatus larvae,showing that T.lewisi is a natural enemy of the Monochamus beetle.T.lewisi larvae prefer to prey on larvae and pupae of M.alternatus rather than on those of T.molitor,showing promising prospect of using the natural enemy T.lewisi for management of Monochamus beetles.

Attack from insect herbivores poses a major threat to plant survival, and accordingly, plants have evolved sophisticated defence systems. Maize is cultivated as a staple crop worldwide, and insect feeding causes large production losses. Despite its importance in agriculture, little is known about how maize reacts to insect herbivory. Taking advantage of advances in sequencing and mass spectrometry technology, we studied the response of maize to mechanical wounding and simulated Mythimna separata (a specialist insect) herbivory by applying its oral secretions (OS) to wounds. In comparison to the responses induced by mechanical wounding, OS elicited larger and longer-lasting changes in the maize transcriptome, proteome, metabolome and phytohormones. Specifically, many genes, proteins and metabolites were uniquely induced or repressed by OS. Nearly 290 transcription factor genes from 39 families were involved in OS-induced responses, and among these, more transcription factor genes were specifically regulated by OS than by wounding. This study provides a large-scale omics dataset for understanding maize response to chewing insects and highlights the essential role of OS in plant-insect interactions.

Summer diapause in Helicoverpa assulta (Hübner), which prolongs the pupal stage, particularly in males, is induced by high temperatures. In the laboratory, 3 rd -, 4 th -, 6 th -instar and prepupal larvae were exposed to high temperatures – 33 and 35 °C with a photoperiod of LD16:8 – until pupation to induce summer diapause. The results showed that the incidence of summer diapause was influenced by temperature, stage exposed and sex. The higher the temperature, the more often summer diapause was attained. Sixth-instar and prepupal larvae were the sensitive stages for summer diapause induction. H. assulta summer-diapausing pupae needed diapause development to resume development when temperatures became favorable. Furthermore, both body mass and energy storage capacity (lipid and glycogen) were significantly affected by diapause rather than sex and were significantly higher in summer-diapausing pupae than in non-diapausing pupae. In addition, the body mass loss and respiration rate showed that the rate of metabolism in the summer-diapausing pupae was consistently lower than in non-diapausing pupae, which were significantly affected by diapause and pupal age. We conclude that summer diapause in H. assulta is a true diapause and H. assulta has evolved mechanisms to accumulate energy storage and to lower its metabolism to adapt to hot summers.

For insects that aggregate on host plants, both attraction and antiaggregation among conspecifics can be important mechanisms for overcoming host resistance and avoiding overcrowding, respectively. These mechanisms can involve multiple sensory modalities, such as sound and pheromones. We explored how acoustic and chemical signals are integrated by the bark beetle Dendroctonus valens to limit aggregation in China. In its native North American range, this insect conducts nonlethal attacks on weakened trees at very low densities, but in its introduced zone in China, it uses mixtures of host tree compounds and the pheromone component frontalin to mass attack healthy trees. We found that exo-brevicomin was produced by both female and male D. valens, and that this pheromone functioned as an antiaggregating signal. Moreover, beetles feeding in pairs or in masses were more likely than were beetles feeding alone to produce exobrevicomin, suggesting a potential role of sound by neighboring beetles in stimulating exobrevicomin production. Sound playback showed that an agreement sound was produced by both sexes when exposed to the aggregation pheromone frontalin and attracts males, and an aggressive sound was produced only by males behaving territorially. These signals triggered the release of exo-brevicomin by both females and males, indicating an interplay of chemical and sonic communication. This study demonstrates that the bark beetle D. valens uses sounds to regulate the production of an antiaggregation pheromone, which may provide new approaches to pest management of this invasive species.