Antifeedant action ofZ-dihydromatricaria acid from soldier beetles (Chauliognathus spp.)

The acetylenic acid,Z-dihydromatricaria acid (DHMA), previously isolated from the defensive secretion ofChauliognathus lecontei, and now shown to occur also inC. pennsylvanicus, is a potent feeding deterrent to jumping spiders (Phidippus spp.). A simple bioassay withPhidippus is described, which is generally applicable to studies dealing with the isolation and evaluation of feeding deterrency of natural products from insects. By use of this assay,Phidippus were shown to be sensitive to as little as 1 μg DHMA, an amount equivalent to less than 2% of the DHMA content ofC. pennsylvanicus.