Acoustic and postural displays in a miniature and transparent teleost fish,Danionella dracula

Abstract

Acoustic behavior is widespread across vertebrates, including among fishes. We report robust acoustic displays during aggressive interactions for a laboratory colony of Danionella dracula, a miniature and transparent species of teleost fish closely related to zebrafish (Danio rerio), which are hypothesized to be sonic based on the presence of a hypertrophied muscle associated with the male swim bladder. Males produce bursts of pulsatile sounds and a distinct postural display–extension of a hypertrophied lower jaw, a morphological trait not present in other Danionella species—during aggressive, but not courtship interactions. Females show no evidence of sound production or jaw extension in such contexts. Novel pairs of size-matched or -mismatched males were combined in resident-intruder assays where sound production and jaw extension could be linked to individuals. In both dyad contexts, resident males produced significantly more sound pulses than intruders. During heightened sonic activity, the majority of highest sound producers also showed increased jaw extension. Residents extended their jaw more than intruders in size-matched, but not -mismatched contexts. Larger males in size-mismatched dyads produced more sounds and jaw extensions compared to their smaller counterparts, and sounds and jaw extensions increased with increasing absolute body size. These studies establish D. dracula as a sonic species that modulates putatively acoustic and postural displays during aggressive interactions based on residency and body size, providing a foundation for further investigating the role of multimodal displays in a new model clade for neurogenomic and neuroimaging studies of aggression, courtship, and other social interactions.

Ultrafast sound production mechanism in one of the smallest vertebrates

“…Despite these similarities, the sounds produced by D. dracula and cerebrum are different. D. dracula males also produce short pulses, around 2 ms in duration, but the inter-pulse interval distribution is broad and has one peak around 35 ms ( 36 ). The duration of the bursts also differs between the two species.…”

“…The duration of the bursts also differs between the two species. D. cerebrum can produce bursts that last on the order of seconds, whereas the longest bursts produced by D. dracula are only 4 to 6 pulses, with bursts of 2 to 3 pulses being more common ( 36 ). The differences in the burst structure may be related to differences in the morphology of their drumming apparatuses as D. dracula have a simpler sound-producing organ ( 20 ) that lacks the bony flanges and connections of the os suspensorium seen in D. cerebrum ( SI Appendix , Fig.…”

Label‐free, whole‐brain in vivo mapping in an adult vertebrate with third harmonic generation microscopy

“…Danionella dracula were available from a breeding colony at Cornell (Tatarsky et al., 2022). Danionella priapus and T. ornatus were obtained from commercial dealers (The Wet Spot Tropical Fish).…”

Label-free multiphoton imaging reveals volumetric shifts across development in sensory-related brain regions of a miniature transparent vertebrate

“…The diversity of environmental niches shaping sensory specialization and behavioral repertoires in fish species has offered significant insights into how relative investment in different brain regions changes from larval stages to adulthood when they exhibit more complex cognitive tasks, such as courtship and aggression (e.g., Toyoda and Uematsu, 1994;Huber et al, 1997;Iribarne andCastello, 2014, Jaggard et al, 2020;Axelrod et al, 2018;Yi et al, 2022). Here, we used third harmonic generation (THG), multiphoton microscopy to map the age-related growth of sensory and sensory-related integration centers in Danionella dracula, a miniature, transparent cyprinid fish that along with other Danionella species has emerged as a new model for investigating the neural basis of adult social behavior (e.g., Schulze et al, 2018;Rajan et al, 2022;Tatarsky et al, 2022;Lee & Briggman, 2023;Zada et al, 2024).…”

“…Here, we used THG imaging and morphometric analysis in live D. dracula from early developmental stages (3 days post-fertilization, dpf) until adulthood (90 dpf) to investigate changes in the relative investment in brain regions deemed especially relevant to sensory mechanisms coupled to acoustic and postural displays in adults (see Tatarsky et al, 2022). The selected regions were also chosen, in part, because of the ease of recognizing defined boundaries using THG across several developmental stages (see Materials and Methods).…”