title: Substrate-borne vibrations induce behavioral responses in the leaf-dwelling cerambycid, Paraglenea fortunei.
abstract: Many insects utilize substrate-borne vibrations as a source of information for recognizing mates or predators. Among various substrates, plant leaves are commonly used for transmitting and receiving vibrational information. However, little is known about the utilization of vibrations by leaf-dwelling insects, especially coleopteran beetles. We conducted two experiments to examine the response of the leaf-dwelling cerambycid beetle, Paraglenea fortunei, to substrate-borne vibrations. We recorded and analyzed vibrations of host plant leaves from four different sources: wind (0.5 m/s), a beetle during landing, a walking beetle, and a beetle walking in the wind (0.5 m/s). We then measured the behavioral thresholds, the lowest amplitudes that induce behavioral responses, from beetles walking and resting on horizontal and vertical substrates with pulsed vibrations ranging from 20 Hz to 1 kHz. The vibrational characteristics of biotic and abiotic stimuli clearly differed. Beetle-generated vibrations (landing, walking, and walking in the wind) were broadly high in the low-frequency components above ∼30 Hz, while wind-generated vibrations showed a dominant peak at ∼30 Hz and a steep decrease thereafter. Among four situations, beetles walking on horizontal substrates showed lowest thresholds to vibrations of 75-500 Hz, which are characteristic of beetle-generated vibrations. Given that P. fortunei beetles are found on horizontal leaf surfaces of the host plant, vibrations transmitted though horizontal substrates may induce a strong freeze response in walking beetles to detect conspecifics or heterospecifics. Our findings provide evidence that leaf-dwelling beetles can discriminate among biotic and abiotic factors via differences in vibrational characteristics.
authors.affiliation: 1 Department of Forest Entomology, Forestry and Forestry Product Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
authors.forename: Remi
authors.initials: R
authors.lastname: Tsubaki
authors.forename: Naoe
authors.initials: N
authors.lastname: Hosoda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitajima
authors.forename: Takuma
authors.initials: T
authors.lastname: Takanashi
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001517:Coleoptera / Q000502:physiology*; D018515:Plant Leaves; D014732:Vibration
keywords: behavior; freeze response; insect; longicorn beetle; vibration