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Substrate-borne vibrations are ubiquitous in nature and are used by diverse taxa to communicate and to obtain information about their environments. However, substrate-borne vibrations remain understudied compared with other sensory and signaling modalities, in part due to human sensory biases. In addition, understanding and quantifying the transmission of vibrations remains a challenging task due to it being dependent on both signal properties and properties of the substrates that the signals transmit through. Here, we provide methods for playing back and measuring the transmission of vibrations throughout a substrate. Using linear resonant actuators, we conducted playbacks of pure tones and frequency sweeps on wooden dowels and on the stems of potted Ptelea trifoliata L. (Rutaceae) plants. We used scanning laser Doppler vibrometry to measure the signals at multiple locations along the length of the dowels and plant stems. We demonstrate that playback of a frequency sweep yields more data in a shorter amount of time than multiple playbacks and measurements of pure tone signals. Our results are also consistent with previous findings showing that signals produce frequency and location specific minima and maxima (nodes and antinodes) throughout the substrates, rather than simply attenuating with distance. This results in filtering of signals, such that their spectra are unique at any given measurement location—illustrating the importance of measuring vibrations at multiple locations. We discuss the implications of such filtering phenomena for vibrationally signaling animals and the biotremologists that study them.

Sensory stimuli are essential for arthropod survival and reproduction. Given the widespread use of vibrational communication among diverse taxa, exploiting vibrational senses has great potential for successful pest management. In this review, we summarize our recent findings on vibration‐based pest management and future perspectives in the context of integrated pest management. We first examine the management of whiteflies – the tobacco whitefly, Bemisia tabaci (Gennadius) and the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) – in various facilities where tomatoes are cultivated. We then explore the recent application of vibration for the control of fungus gnats of the genus Neoempheria (Diptera: Mycetophilidae) infesting shiitake mushrooms. Finally, we discuss the control of the brown‐winged green stink bug, Plautia stali Scott (Hemiptera: Pentatomidae), a pest of fruit trees in Japan. Notably, our trials have demonstrated that vibrational treatments are profitable not only for reducing pest populations but also for indirect benefits such as increased crop yields or the enhancement of pest control effectiveness. [ABSTRACT FROM AUTHOR]

Abstract: Temperature affects ectotherms in a variety of ways. These effects can be especially complex in sexual behaviors, as different sexes may be affected differently by temperature. We examined this in the jumping spider, Habronattus clypeatus. In this species, males court females using visual and vibratory signals. We tested whether key intersexual behaviors would change with temperature in similar, predictable ways across males and females. We first measured temperature and apparent activity of individuals across the day. We found that H. clypeatus are active across a wide range of temperatures (11–56 °C) and are most active at times of day when temperature ranges from 13 to 46 °C. Next, we performed mating experiments across behaviorally relevant temperatures. Females were more likely to allow males to progress to later stages of courtship and had higher mating rates at higher temperatures. Male visual and vibratory courtship behaviors generally became faster, higher-pitched, and lower in amplitude at higher temperatures. This relationship between temperature and signal aspects attained a roughly curvilinear shape, with an asymptote around 40 °C. Intriguingly, mating rates in the lab were highest at temperatures potentially above those during peak spider activity in the field. Our results suggest that temperature’s effects on behavior are complex and can affect males and females differently. This work emphasizes that understanding temperature effects on mating is critical to understanding sexual selection patterns particularly in species which use complex signals. Significance statement: Temperature affects communication in most ectothermic species. Previous research has shown that temperature changes courter signals and chooser choice. However, this has never been investigated in species that use multimodal signals. We investigate how signals and choice change across temperatures in a desert-dwelling jumping spider. Using field temperature/activity modeling and a series of courtship experiments in the lab, we show that male signals and female choice change with temperature across biologically relevant ranges. Our results suggest that the temperatures at which mating is most likely occur at times of the day when animals are least active. These counterintuitive results highlight the importance of understanding how behavior in a controlled lab environment corresponds to natural field conditions as well as the importance of examining the effects of naturally occurring environmental variation on behavior.

Anurans are known to detect vibrations, but few studies explore relationships between vibrations and resultant behaviors. We studied the reaction of calling captive-bred male midwife toads (Alytes obstetricans) to the randomized playback of a vibrational crescendo stimulus train. We considered two sources of natural abiotic vibrational stimuli: rainfall and wind. Rainfall was expected to induce calling and wind was expected to inhibit it. Playback experiments with two synthetic tones (200 Hz and 300 Hz) tested the sensitivity to pure tones and could possibly reveal a hearing sensitivity trend between these frequencies. The toads did not increase call rate in response to rainfall vibrations and only one of the five wind stimulus levels caused a significant decrease in call rate. This limited response could be explained, because the tested toads came from a captive population, where emergence may not be mediated by rainfall vibrations. We found that A. obstetricans is highly sensitive to very low frequencies, which could explain the sensitivity observed to vibrational stimuli. Playback of a random crescendo stimulus train proves to be a valid approach for addressing behavioral questions. However, the use of a captive population may have been a limitation in the clarity of the results. [ABSTRACT FROM AUTHOR]

Plants influenced the evolution of plant-dwelling stink bugs’ systems underlying communication with chemical and substrate-borne vibratory signals. Plant volatiles provides cues that increase attractiveness or interfere with the probability of finding a mate in the field. Mechanical properties of herbaceous hosts and associated plants alter the frequency, amplitude, and temporal characteristics of stink bug species and sex-specific vibratory signals. The specificity of pheromone odor tuning has evolved through highly specific odorant receptors located within the receptor membrane. The narrow-band low-frequency characteristics of the signals produced by abdomen vibration and the frequency tuning of the highly sensitive subgenual organ vibration receptors match with filtering properties of the plants enabling optimized communication. A range of less sensitive mechanoreceptors, tuned to lower vibration frequencies, detect signals produced by other mechanisms used at less species-specific levels of communication in a plant environment. Whereas the encoding of frequency-intensity and temporal parameters of stink bug vibratory signals is relatively well investigated at low levels of processing in the ventral nerve cord, processing of this information and its integration with other modalities at higher neuronal levels still needs research attention.

In the recent years, vibrational communication signals have become more and more prominent in research—often, characteristics of signals are described for several closely related species or populations of the same species, using means and standard deviations. Phenotypic variation in vibratory communication signals can be measured and compared using the coefficient of variation, which is supposed to be independent of trait size. However, it has been shown that the coefficients of variation of acoustic (airborne sound) male courtship signals in insects and anurans increase with signal duration in accordance with a power law. To examine whether this pattern is also true for vibrational communication signals, we used original data for Mantophasmatodea and reviewed the literature for published data on arthropods, anurans and mammals. The relationship between trait variability and duration is surprisingly stable for all investigated biotremology data and similar to the relationships found for airborne sound courtship signals. This study adds towards our knowledge about a general pattern for temporal variability of communication signals. [ABSTRACT FROM AUTHOR]

Vibrations are a ubiquitous source of information in the environment, and are utilized by a wide range of animals. In this review, I concentrate on the propagation of vibrations across and through substrates, which are materials and surfaces. During the propagation process, physical constraints act on vibrational signals and cues, including loss of energy, filtering or distortion of information. An understanding of these physical mechanisms is important for answering biological questions about communication and information gathering, particularly the reach of signals/cues and how information can be separated from background noise. In this review, I explore the interdisciplinary links central to the field of biotremology to probe the extent to which physical laws limit information propagation. In what follows, I start with a primer in wave theory, before focusing on how the physical factors of wave type and substrate properties affect vibration propagation. I then turn to the interacting biological factors that influence signal/cue propagation during animal-substrate coupling, discussing the numerous behavioural and morphological adaptations employed to mitigate physical constraints. Following this, I then move from limits to possibilities, discussing how animals harness physical laws to provide useful information. Using examples from a wide range of animal systems and biological contexts, I highlight the array of evolutionary strategies to promote the propagation of information given inevitable physical constraints. [ABSTRACT FROM AUTHOR]

A study was undertaken to determine whether Scolypopa australis, the passionvine hopper, communicates using substrate-borne vibrations, as its use of such signals for communication is currently unknown. This insect is a costly pest to the kiwifruit industry in New Zealand, where few pest management tools can be used during the growing season. Vibrations emitted by virgin females and males of S. australis released alone on leaves of Griselinia littoralis were recorded with a laser vibrometer to identify and characterise potential spontaneous calling signals produced by either sex. In addition to single-insect trials, preliminary tests were conducted with female–male pair trials to determine whether individuals exchanged signals. The signal repertoire of S. australis includes a male calling signal and two female calling signals. However, no evidence of duetting behaviour that is potentially necessary for pair formation has been found to date. Our outcome suggests that a deeper understanding of the role of vibrational communication employed by S. australis is needed, and by disclosing the pair formation process, a new residue-free pest management tool against this pest may be developed. In addition, this vibration-based tool could contribute to future biosecurity preparedness and response initiatives. [ABSTRACT FROM AUTHOR]

Simple Summary: Plant-dwelling stink bugs communicate with chemical and plant-borne vibratory signals that are altered when transmitted through the substrate and air. Mates are attracted to the same plant by pheromones, where they exchange information through mechanical and close-range chemical signals. Plants absorb odor molecules from insects and produce kairomones that can enhance or reduce insect responses to pheromones. Long-range communication between stink bug mates in the field occurs exclusively via pheromones. The species specificity of the sex-pheromones guarantees their success in finding mates in the plant environment. Substrate-borne communication occurs in a narrow frequency range that is tuned to the mechanical properties of the plant. Vibratory signals are transmitted with low attenuation and with altered frequency, amplitude, and temporal characteristics. The frequency sensitivity of the subgenual organ is tuned to the low-frequency resonant properties of the plants. Recognition is encoded in the vibratory signal species- and sex-specific temporal parameters and directionality in the time delay between signals arriving from different directions. The characteristics of behaviorally described multimodal close-range communication on a plant are under-investigated. Studies of neuronal processing of multimodal sensory signals in the stink bug brain are needed to understand how their integration affects behavioral responses. Plants influenced the evolution of plant-dwelling stink bugs' systems underlying communication with chemical and substrate-borne vibratory signals. Plant volatiles provides cues that increase attractiveness or interfere with the probability of finding a mate in the field. Mechanical properties of herbaceous hosts and associated plants alter the frequency, amplitude, and temporal characteristics of stink bug species and sex-specific vibratory signals. The specificity of pheromone odor tuning has evolved through highly specific odorant receptors located within the receptor membrane. The narrow-band low-frequency characteristics of the signals produced by abdomen vibration and the frequency tuning of the highly sensitive subgenual organ vibration receptors match with filtering properties of the plants enabling optimized communication. A range of less sensitive mechanoreceptors, tuned to lower vibration frequencies, detect signals produced by other mechanisms used at less species-specific levels of communication in a plant environment. Whereas the encoding of frequency-intensity and temporal parameters of stink bug vibratory signals is relatively well investigated at low levels of processing in the ventral nerve cord, processing of this information and its integration with other modalities at higher neuronal levels still needs research attention. [ABSTRACT FROM AUTHOR]

Summary Living in the African savanna is dangerous, especially for plants. Many plants therefore engage in mutualism with ants, in which plants provide food and shelter in exchange for protection against herbivores. Ants become alarmed when the plant takes on some sort of damage. They immediately emerge from their plant shelter and aggressively defend the plant. Mammalian herbivores can have devastating effects on trees by browsing, breaking tree branches, stripping bark, and pushing over entire trees. However, mutualistic ants substantially reduce the amount of damage. To efficiently protect the tree, ants need to rapidly react together when the tree is under attack. Here, we show that the acacia ant Crematogaster mimosae defends its host tree by exploiting plant-borne vibrations caused by browsers feeding on the tree. Experiments with controlled vibrations show that ants discriminate browser-induced vibrations from those induced by wind, become alarmed, and patrol on the branches. Browser-induced vibrations serve as a long-distance alarm cue. The vibrations propagate through the whole acacia tree and trigger ants' defensive behavior, even on the other side of the tree. Furthermore, the ants make use of tropotactic directional vibration sensing to orient to the attacked part of the tree and fight back the attacker. Highlights • Acacia ants discriminate browser-induced vibrations from wind-induced vibrations • Browser-induced vibrations serve as a long-distance alarm cue for ants • Acacia ants make use of tropotactic directional vibration sensing Hager and Krausa show that the acacia ant Crematogaster mimosae defends its host tree by exploiting plant-borne vibrations caused by browsers feeding on the tree. Browser-induced vibrations serve as a long-distance alarm cue, and the ants make use of tropotactic directional vibration sensing to orient to the attacked part of the tree. [ABSTRACT FROM AUTHOR]