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ABSTRACT Stridulation, acoustic communication produced by friction between specialized body structures, is a poorly studied antipredator mechanism. Scorpions may display multiple defensive responses, yet acoustic signaling in such defensive context remains poorly studied. Given the sexual dimorphism commonly observed in scorpion body size and pectines, the latter, which may be involved in sound production, could vary morphologically and result in acoustic differences. We hypothesized that (1) stridulatory apparatus of the scorpion Jaguajir rochae (Borelli, 1910) is sexually dimorphic, (2) sexual dimorphism in stridulatory structures affects acoustic parameters, and (3) stridulatory responses vary with stress, tested via (2.1) mechanical and (2.2) mechano‐chemical stimulation. Sound‐producing structures and acoustic parameters were measured and stridulation was tested under high/low mechanical stress and mechano‐chemical stress, the latter using chemical cues from a mammalian predator. Females exhibited larger pectinal structures, whereas males showed a higher allometric ratio relative to body size. Stridulatory signals in J. rochae showed sexual differentiation primarily in delta time, dB Sound Pressure Level, and low frequency, as revealed by Principal Component Analysis, what explains 38.7% of acoustic variance. Females produced longer and more intense signals, whereas males exhibited slightly higher peak frequencies. Yet, the occurrence of stridulatory responses was similar across different stress treatments. These findings reveal that sexual dimorphism in stridulatory apparatus influences acoustic parameters and that stridulation in J. rochae can be triggered by mechanical stimulation, supporting its role as a defensive behavior. This study provides the first evidence of sex‐specific acoustic variation in scorpion stridulation and elucidates its function as an antipredator strategy.
Dionisio-da-Silva et al. (Mon,) studied this question.