Mechanistic origins of bombardier beetle (Brachinini) explosion-induced defensive spray pulsation

Bombardier beetles (Brachinini) use a rapid series of discrete explosions inside their pygidial gland reaction chambers to produce a hot, pulsed, quinone-based defensive spray. The mechanism of brachinines’ spray pulsation was explored using anatomical studies and direct observation of explosions in...

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Bibliographic Details
Main Authors: Arndt, Eric Michael, Moore, Wendy, Lee, Wah-Keat, Ortiz, Christine
Other Authors: Massachusetts Institute of Technology. Department of Materials Science and Engineering
Format: Article
Language:en_US
Published: American Association for the Advancement of Science (AAAS) 2015
Online Access:http://hdl.handle.net/1721.1/96867
https://orcid.org/0000-0003-3511-5679
Description
Summary:Bombardier beetles (Brachinini) use a rapid series of discrete explosions inside their pygidial gland reaction chambers to produce a hot, pulsed, quinone-based defensive spray. The mechanism of brachinines’ spray pulsation was explored using anatomical studies and direct observation of explosions inside living beetles using synchrotron x-ray imaging. Quantification of the dynamics of vapor inside the reaction chamber indicates that spray pulsation is controlled by specialized, contiguous cuticular structures located at the junction between the reservoir (reactant) and reaction chambers. Kinematics models suggest passive mediation of spray pulsation by mechanical feedback from the explosion, causing displacement of these structures.