I only saw a handful of insects yesterday when I went out to look along the road near my home. The most remarkable of these (and the easiest to see) without magnifying tools, was the slender, brown rove beetle with the sunshine tail!
Gold and Brown Rove Beetles are fairly small, slender, and typically pretty agile. They have a brown body with little yellow hairs (setae) at the end of their “tail.” Another patch of this golden setae wraps around their “belly,” like a little yellow ‘belt,’ This one was indeed on the smaller side at about 12 mm. However, given the outdoor temperature was still pretty low, it wasn’t agile enough to escape a short photo session.
I’ll admit, I poked it (very gently) to see if I could get a photo of it with its tail up. When threatened, they have defense glands that emit a chemical fluid. I found out (after reading through the Journal of Chemical Ecology from 1990) that researchers found this defense fluid is made up primarily of a chemical called iridodial (Huth and Dettner, 1990).
Here’s a photo of my beetle exuding the defense fluid! Note the little white bubble at the end of its tail.
Here in the next photo, you can see it without the defense fluid.
Being curious, I had to investigate a bit about the chemical properties of iridoids. I was intrigued to learn that “iridoids are secondary metabolites present in various plants, especially in species belonging to the Apocynaceae, Lamiaceae, Loganiaceae, Rubiaceae, Scrophulariaceae and Verbenaceae families, Viljoen et al., (2012).” Tundis et. al., (2008) found that “iridoids exhibit a wide range of bioactivity, such as neuroprotective, antinflammatory and immunomodulator, hepatoprotective and cardioprotective effects.” Findings also included iridoid compounds also possessed anticancer, antioxidant, antimicrobic, hypoglycaemic, hypolipidemic, choleretic, antispasmodic and purgative properties (Tundis et al., 2008).
While I didn’t find much information (yet) utilizing iridoid secretions from insects, I did begin to wonder if that tiny drop of fluid could have provided some anti-inflammatory benefit for the migraine headache I’d been suffering from for days. I’ve been working with a friend of mine who is a research pharmacokineticist, helping to edit his papers and those of some associates he has in China. Probably, I’ll pass this along since they’re always looking for ideas on how to develop/synthesize new pharmaceuticals and biomimicry seems to be the new frontier.
Huth, A. and K. Dettner. 1990. Defense chemicals from abdominal glands of 13 rove beetle species of sub tribe Staphylinia (Coleoptera:Staphylinidae, Staphylininae). Journal of Chemical Ecology, 16:9, pp 2691-2711.
Tundis, R., Loizzo, M.R., Menichini, F., Statti, G.A., and F. Menichini. 2008. Biological and Pharmacological Activities of Iridoids: Recent Developments, Mini-Reviews in Medicinal Chemistry. 8: 399. https://doi.org/10.2174/138955708783955926
Viljoen A., Mncwangi N., Vermaak I. Anti-inflammatory iridoids of botanical origin. 2012. Curr. Med. Chem. 19:2104–2127. doi: 10.2174/092986712800229005