The Goldenrod Soldier Beetle Chauliognathus pensylvanicus is a common sight on goldenrod and other fall flowers in Indiana. These beetles spend much of their time mating or feeding on pollen in plain sight during the day. The yellow and black warning colors suggest toxicity or unpalatability.
A group of scientists* investigated the chemical defenses of these beetles. There are 9 pairs of defensive glands that secrete droplets of fluid when the beetles are disturbed. The droplets contain Z-dihydromatricaria acid a substance that is deterrent to spiders and other common predators. A robust anti-predator defense allows the beetles to spend more time feeding and mating and less time running and hiding.
* Eisner, Thomas; Hill, David; Goetz, Michael; Jain, Subhash; Alsop, David; Camazine, Scott. 1981. Antifeedant action ofZ-dihydromatricaria acid from soldier beetles. Journal of Chemical Ecology. 7:1149-1158.