Acoustic communication in Dendroctonus adjunctus Blandford (Curculionidae Scolytinae): description of calls and sound production mechanism

• DOI: https://doi.org/10.22533/at.ed.5962513016

• Palavras-chave: -

• Keywords: bioacoustics, bark beetle, elytro-tergal, single and multiple-noted calls, withdrawal call.

• Abstract: Acoustic communication system (ACS) in bark beetles has been studied mainly in species of the genera Dendroctonus, Ips, and Polygraphus. Specifically, ACS of the roundheaded pine beetle, Dendroctonus adjunctus, has been little studied. In this study, we described the stridulatory apparatus of this beetle using optical and scanning electron microscopy and recorded the call types produced by males in three behavioral contexts: stress, male-female, male-male interactions. From the spectrograms and waveforms, call types, as well as temporal (tooth strike, tooth strike rate and intertooth strike interval) and spectral features (minimum, maximum and dominant frequency) were determined. Males have a functional elytro-tergal stridulatory apparatus, females not, consisting of a file for the pars stridens and two lobes for the plectrum. Most of spectro-temporal features were statistically different between single- and multi-noted calls and across the three behavioral contexts. In the male-male interaction, a new type of call named "withdrawal" was produced by the male withdrawing or fleeing. Our results suggest that the spectro-temporal features of single- and multiple-noted calls in the three behavioral conditions are specific and different from each other. Yet, the combination of single and multiple calls determinate an overall calling pattern characteristic of the tested behaviors and, therefore species-specific.