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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

The goldenrod gang - goldenrod soldier beetle, Chauliognathus pennsylvanicus, the black blister beetle, Epicauta pennsylvanica, and the jagged ambush bug, Phymata pennsylvanica


The goldenrod soldier beetle eats nectar, pollen, and garden pests.


Over the past several weeks the nearby meadow has been the place for encounters with three of the toughest hombres in the bug world – the goldenrod gang. Goldenrod is one of the very best places to encounter bugs this time of the year. The first gangsta I encountered was the goldenrod soldier beetle. Like other members of its clan, this insect is a killer in both the adult and juvenile stage. When not tanking up on nectar and pollen of goldenrod or flowers in your garden, adults feed on plant pests such as aphids and caterpillars. The juvenile stages, larvae, of the goldenrod soldier beetle are important predators of ground dwelling insects. They are dark gray and cloaked in a thick, velvety coat of fine hairs. They are often seen about this time of year hunting in flowerbeds or on your sidewalk or patio. Sometimes they are numerous and find their way into your home beneath the door sweep. They spend the winter in the soil and leaf litter in your garden.

The black blister beetle produces potent irritants called cantharidins.

Nearby on another flower head was the black blister beetle. This is not an insect to be taken lightly.If handled roughly or crushed against your skin, blister beetles release their blood that is laced with potent irritants called cantharidins. Upon contacting skin these compounds can raise nasty looking blisters. Blister beetles feeding on plants in meadows have been inadvertently bailed in hay and fed to horses. The toxic cantharidins in their bodies have caused poisoning deaths of several horses. Blister beetles are also the source of the aphrodisiac and medicinal compound called Spanish fly. As was common medical practice at the time, Spanish fly was applied to the neck of a mortally ill George Washington in an attempt to draw out the inflammation that afflicted him on the day of his death. Unfortunately, this therapy proved unsuccessful. The larvae of blister beetles also lead interesting lives. The tiny larvae of blister beetles are called triungulans. In some species triungulans climb aboard a bee as it visits the goldenrod flower and then hitch a ride back to the nest. There the vagabonds jump off the bee and consume the developing bee brood in the hive. Other species like our black blister beetle scurry on the ground and locate nests of grasshopper eggs. The underground omelet becomes a banquet for the developing blister beetle larvae.

Powerful forelegs enable the ambush bug to capture its prey. 

Beautifully camouflaged, this ragged ambush bug awaits a victim.

The stealthiest member of this terrible trio is the jagged ambush bug. Like our friend the praying mantid, the ambush bug is a sit and wait predator. Its irregular body outline and beautiful patchwork of yellow, green, and brown enables it to blend in with the yellow, green, and brown patterns of the goldenrod flower head. The ambush bug will sit and wait for hours motionless, but when an unsuspecting fly or bee lands for a sip of nectar, wham, the ambush bug attacks. It flicks out powerful raptorial forelegs that catch its victim in a death grip. It then inserts a stout beak into the body of the prey, injects saliva, and then sucks its blood. The immature stages of the ambush bugs are also generalist predators and kill a wide range of visitors to the goldenrod patch. In October the meadow is grand. Take time for a walk to observe the goldenrod gang and their prey.


For more information on soldier beetles, blister beetles, and ambush bugs visit the following web sites: