Saturday 8 June 2024

Air-bags Deployed!

On a recent trip I learned something interesting about Malachite Beetles.  I popped a specimen in my new spi-pot for a quick record shot and when I looked at the photo I noticed four triangular triangular pinkish "things" attached to it.

Common Malachite Beetle - Malachius bipustulatus

They didn't look like ectoparasites so I wondered if they could be orchid pollinia, lots of Common Spotted-orchid being present. However, when I asked on Facebook Michael Geiser kindly informed me that these structures are in fact a chemical defence system consisting of inflatable membranous "air-bag" like pockets. These produce a pheromone presumably targeted at ants and other smaller predators, to fend them off. All members of Malachiinae have this kind of chemical defence, inflate their "air bags" when feeling threatened. 

On release, the beetle wandered off unharmed, presumably quite pleased with itself - but who knows what goes on in the mind of a Malachite Beetle?
 


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