Monochamus alternatus (Hope) is a severe wood‐boring pest in coniferous forests and a major vector of pine wilt disease in East Asia. Harmonic radar is a powerful tool for studying the dispersal behavior of insects and it could be applied to control pine wilt disease. In this study, we validated the application of harmonic radar for analyzing the dispersal behavior of M. alternatus beetles in a field environment. We determined the wing capacities of the beetles and the effects of electronic tagging and marking on their movement, flight ability, survivorship, and food consumption in the laboratory to confirm the suitability of this technique. The detection rate and recovery rate for beetles were analyzed separately using radar on caged pine stands and in the field environment. The results showed that the minimum wing capacity of the Japanese pine sawyer was 24.9 mg, which was seven times the weight of the electronic tag (3.5 mg). Marking and tagging the beetles had no significant adverse effects on their movement, flight capacity, food consumption, and survivorship. The detection rate using the radar system and recovery rate based on visual observations of the beetles in caged pines were both 95.6%. However, in the field environment, the detection and recovery rates were only 55.6% and 37.8% after one week, respectively, and 33.3% and 7.8% after two weeks. Harmonic radar is a promising technique for studying the dispersal behavior of the Japanese pine sawyer, but its performance is not satisfactory and major improvements are required for both the radar system and electronic tags.

Abstract. Many moths possess ultrasound-sensitive ears, directly resulted from bat predation. Moth ears display an abundant diversity due to their body location, accessory structures, and number of auditory sensory cells. Anatomically, the moth ears are the simplest hearing organs in insects and most are tympanal organ with a tympanum. Eared moths have an optimal frequency range between 20 kHz and 50 kHz, which coincides with the peak frequency used by most insectivorous bats. The primary function of the moth ear is to detect and avoid the hunting of bats. Eared moths show a series of defensive behaviors, when they are exposed to the cries emitted by insectivorous bats. The presence of these tympanal organs also set the stage for the later evolution of ultrasonic courtship signals in the eared moth families. Over the years, entomologists worldwide have performed large numbers of studies on hearing of moths and their interactions with bats. This paper presents an overview of moth hearing, focusing on morphology, neurophysiology, and behavioral ecology.Résumé. L'audition ultrasonique chez les papillons nocturnes. Beaucoup de papillons de nuit ont des organes d'audition sensibles aux ultrasons, ce qui résulte d'une adaptation à la prédation par les chauve-souris. Ces organes d'audition présentent une abondante diversité en ce qui concerne leur position sur le corps, leur structure, et par le nombre de cellules sensorielles. Anatomiquement, ces organes d'audition ont une fréquence optimale de réception comprise entre 20 et 50 kHz, ce qui coincide avec le pic des fréquences utilisées par la plupart des chauves-souris insectivores. La fonction primaire de ces organes est de détecter la chasse par les chauves-souris et de permettre d'y échapper. Les espèces pourvues de ces organes présentent toute une série de comportements défensifs dès qu'elles sont exposées aux cris émis par les chauves-souris. La présence d'organes tympaniques parvient à un stade tel qu'elle permet l'évolution de signaux ultrasoniques de parade nuptiale chez plusieurs familles. Depuis longtemps, les entomologistes du monde entier ont fait de nombreuses études sur l'audition des papillons nocturnes et ses interactions avec les chauves-souris. Le présent article présente une revue de l'audition de ces lépidoptères, avec une attention particulière sur la morphologie, la neurophysiologie et l'éco-éthologie.

It is well known that noctuid moths respond to ultrasound frequencies produced by insectivorous bats performing a series of evasive maneuvers such as loops, dives, rolls, and turns. Certain ultrasound frequencies may be considered an environmental stress factor for these moths, causing physiological and behavioral effects. We investigated changes in acetylcholinesterase activity of Helicoverpa armigera (Hübner) exposed to ultrasound produced from a commercial device (LHC20). Our results indicated that stress effects on acetylcholinesterase activity resulting from exposure to ultrasound do not differ according to sex, but effects on different developmental stages of H. armigera differ significantly depending on duration of exposure. Enzyme activity increased in adults after 20 min exposure to ultrasound and decreased in pupae after 30 and 50 min exposure. Enzyme activity in larvae was reduced after 20 min and increased after 40 and 60 min. The results of this study also indicate that stress caused by exposure to ultrasound could modulate the cholinergic system in H. armigera.

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