Tremulatory and Abdomen Vibration Signals Enable Communication through Air in the Stink Bug Euschistus heros

Abstract

Communication by substrate-borne mechanical signals is widespread among animals but remains one of their least understood communication channels. Past studies of vibrational communication in insects have been oriented predominantly to communication during mating, showing that species- and sex-specific vibrational signals enable recognition and localization of potential mates on continuous solid substrates. No special attention has been paid to vibrational signals with less obvious specificity as well as to the possibility of vibrational communication across substrates that are not in physical contact. We aimed to reinvestigate emission of the aforementioned vibrational signals transmitted through a plant in the stink bug Euschistus heros (Pentatomidae: Pentatominae) and to check whether individuals are able to communicate across adjecent, physically separated substrates. We used laser vibrometry for registration of substrate-borne vibrational signals on a bean plant. Using two bean plants separated for 3 to 7 cm between two most adjacent leaves, we investigated the possibility of transmission of these signals through air. Our study showed that males and females of E. heros communicate using tremulatory, percussion and buzzing signals in addition to the previously described signals produced by vibrations of the abdomen. Contrary to the latter, the first three signal types did not differ between sexes or between pentatomid species. Experiments with two physically separated plants showed significant searching behaviour and localization of vibrational signals of an E. heros male or a female, in response to abdominal vibration produced signals of a pair duetting on the neighbouring plant, in comparison to control where no animals were on the neighbouring plant. We also confirmed that transmission through air causes amplitude and frequency decay of vibrational signals, which suggests high-amplitude, low-frequency tremulatory signals of these stink bugs their most plausible way of communication across discontinuous substrates.

Vibrational communication of the brown marmorated stink bug (Halyomorpha halys)

“…The vibrational signals of H. halys in this stage notably include tremulation, which is a separate mechanism involving the production of short, broadband pulses by shaking the whole body. Such signals are described during courtship for other Pentatomid species, such as Podisus maculiventris (Žunič et al ., ) and Euschistus heros (Kavčič et al ., ). Furthermore, numerous transitions between song types are observed, perhaps hinting at the evolution of signal repertoires from a ‘basic’ type.…”

Tremulation display in male agonistic behavior of the black-eyed leaf frog (Agalychnis moreletii: Hylidae).

“…Hill and Wessel (2016) define tremulation as a shaking or trembling behavior that induces vibrations in the substrate, often through the legs, with no percussive impact. This communication via surface-borne vibrations is widely documented in arthropods, such as orthopterans (Cocroft, Shugart, Konrad, & Tibbs, 2006) and hemipterans (Kavčič, Čokl, Laumann, Blassioli-Moraes & Borges, 2013), but also had been reported in some vertebrates, such as tree frogs (Caldwell et al, 2010), salamanders (Christensen, Lauridsen, Christensen-Dalsgaard, Pedersen, & Madsen, 2015) and seals (Bishop, Denton, Pomeroy, & Twiss, 2015). The analysis of this vibrational signaling in animals, known as biotremology, allows a better understanding of communication through these signals, the propagation process in the environment and how physical variables affect this behavior (Mortimer, 2017).…”

Stink Bug Communication with Multimodal Signals Transmitted through Air and Substrate

“…Nevertheless, Eriksson et al [44] described signalling between a male and female leafhopper Scaphoideus titanus (Ball) by vibratory signals transmitted over the air at a six cm distance between mechanically isolated leaves. Kavčič et al [45] confirmed airborne communication up to six cm distance in the stink bug species E. heros. During transmission through the air between mechanically isolated leaves, signal spectra become narrower by increased attenuation of frequencies above 300 Hz, and the signal's amplitude decreases by 20 to 30 dB at three cm and by 25 to 35 dB at six cm distance.…”

“…Tremulatory signals are produced by vigorous shaking of the whole body parallel to the substrate, with legs firmly standing on it [51,81,82]. Tremulatory signals produced in Pentatominae [45] and Asopinae [81] share common amplitude, temporal and frequency characteristics. The characteristic plant-recorded tremulatory signals of amplitudes up to 5 mm/s, duration below 0.5 s and irregular repetition rate are composed of a short, high frequency onset followed by the longer low frequency tail with the decaying amplitude resembling plant resonance.…”

“…Buzzing signals, produced by vibration of lifted wings, represent another less species-specific high-amplitude vibratory emission [45]. The velocity of E. heros plant-recorded buzzing signals reached 40 mm/s, and the duration of irregularly produced signals varied within and between individuals from 0.5 s to minute-long continuous emissions.…”