This colorful beetle was found on the Henning CA field trip, crawling on a forest plant. It looks like it had a bad paint job on its elytra (wing cases) which has been chipping off. This is a sumac flea beetle (Blepharida rhois) and it is supposed to look like that. Actually in one life stage it makes a stink when it covers itself with makeup, but we will get to that later.
|Sumac Flea Beetle (Blepharida rhois) -wiki.bugwood.org|
|Sumac Flea Beetle Larvae- wiki.bugwood.org|
Now about that smelly makeup. Like other beetles in the Blepharida flea beetle genus, the larvae of B. rhois retain their feces on their back rather than discarding it, a practice referred to as a "shield defense." A study by Venci and Morton in Chemoecology showed that predatory ants attacked all the uncoated larvae and none of those bearing this shield.
|Another species example of fecal shield defense Zookeys|
"The shield defense was a mixture of three fatty acids, a suite of tannins, their metabolites and phytol. All shield compounds or their precursors were obtained entirely from the host plant. Pure standards of shield compounds were found to be deterrent when assayed. This is one of the first instances of an insect using a mixture of primary and secondary substances for defense against predators." Shield defense paperEverything in nature is eventually recycled. In this case the sumac flea beetle has gone beyond the recycling trend, practicing what is called in current terminology "repurposing."
This is one of a series on finds on the Master Naturalist training field trip. More pictures from the field trip are at Finds from the Field.