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

TitleMechanistic origins of bombardier beetle (Brachinini) explosion-induced defensive spray pulsation
Publication TypeJournal Article
Year of Publication2015
AuthorsArndt, EM, Moore, W, Lee, W-K, Ortiz, C
JournalScience
Volume348
Issue6234
Pagination563 - 567
Date Published2015/05/01/
Abstract

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.