Polychaete Leocratides kimuraorum
Sponge-dwelling Polychaete (Worm)
Polychaete ( Leocratides kimuraorum) in Lab
A sponge-dwelling polychaete worm produces an impulsive intense “pop” sound in a laboratory setting when it comes into contact with another polychaete. This behavior has been termed by the authors as “mouthfighting”. Audio shortened for the purposes of creating Spectrogram. Sound from Goto et. al. 2019. Used with permission from Elsevier.
Description
The marine polychaete Leocratides kimuraorum (Ref 1, Ref 2) is a bristle worm that has been found in the western Pacific inhabiting sponges at water depths of 85 to 170 meters (279 to 556 feet). L. kimuraorum can be up to 2.9 centimeters (just over 1 inch) long with a semi-translucent body and long tentacles. Several individuals find refuge in one sponge host. Their host sponges are commonly known as glass sponges, or scientifically as hexactinellids, which are sponges with an internal skeletal structure made of intricate four or six-pointed silica particles called spicules.
Polychaetes of this species in lab aquaria produced impulsive sounds when interacting with each other (Ref 3). These sounds, termed “mouth-fighting” by the authors, were hypothesized to be related to agonistic (associated with conflict), territorial behavior while living in its host sponge. Scientists report worms produced “sound pressures up to 157 dB re 1 μPa at 1 m, with frequencies in the 1–100 kHz range and a strong signal at ∼6.9 kHz” (Ref 3). The sounds are similar to crustacean snapping shrimp sounds in their brevity, intensity, and frequency spectrum (Ref 4–Ref 5), which is a surprising find given these semi-transparent organisms are soft-bodied. While the actual mechanisms of sound production have not been determined yet, scientists have hypothesized that some marine worms produce cavitation by extremely rapid expansion of their muscular pharynx (“throat”), which produces a loud pop or a snap.
Typical examples of mouth fighting of Leocratides kimuraorum (three sequences with sound at normal video frame rate, 30 fps) and a slow-motion sequence (120 fps). A loud popping sound is produced when the worm performs mouth-attacking behavior. Reprinted from: Goto, R., Hirabayashi, I., & Palmer, A. R. (2019). Remarkably loud snaps during mouth-fighting by a sponge-dwelling worm. Current Biology, 29(13), R617–R618. Used with permission from Elsevier.
Resources
Live Science: Tiny Fighting Worms Make One of the Loudest Sounds in the Ocean
World Register of Marine Species (WoRMS) taxon details
Learn more about this specific species:
https://www.marinespecies.org/aphia.php?p=taxdetails&id=1047980#attributes
References
(1) Jimi, N., Tanaka, M. & Kajihara, H. (2017). Leocratides (Annelida: Hesionidae) from the Pacific Coast of Middle Honshu, Japan, with a Description of Leocratides kimuraorum sp. nov.. Species Diversity, 22(2), pp.133–141. https://doi.org/10.12782/specdiv.22.133
(2) Kim, H., & Min, G.-S. (2021). The First Record of Leocratides kimuraorum (Annelida, Hesionidae) from Korea, with DNA Barcode Data. Animal Systematics, Evolution and Diversity, 37(3), 219–224. https://doi.org/10.5635/ASED.2021.37.3.015
(3) Goto, R., Hirabayashi, I. & Richard, P.A. (2019). Remarkably loud snaps during mouth-fighting by a sponge-dwelling worm. Current Biology, 29(13), R617–R618. https://doi.org/10.1016/j.cub.2019.05.047
(4) Versluis, M., Schmitz, B., von der Heydt, A., & Lohse, D. (2000). How Snapping Shrimp Snap: Through Cavitating Bubbles. Science, 289(5487), 2114–2117. https://doi.org/10.1126/science.289.5487.2114
(5) Au, W., & Banks, K. (1998). The acoustics of the snapping shrimp Synalpheus parneomeris in Kaneohe Bay. Journal of The Acoustical Society of America – J ACOUST SOC AMER, 103, 41–47. https://doi.org/10.1121/1.423234