Blister Beetle


Ash-Gray Blister Beetle ----->



<-----  Striped Blister Beetle


The Blister Beetle can take care of itself.  If any of you have made the mistake of handling one of these beauties you may have gotten a rather rude surprise -- painful blisters.  I made the mistake of brushing one off my neck one evening when it had gotten its bearings all wrong and assumed I was a nice tall plant for resting. It left a water blister that was painful for days. These guys mean business! This is a defense mechanism the military would be envious of.

In Missouri the two most common are the Striped Blister Beetle and the Ash-gray Blister Beetle. They are both in the family Meloidae in the Order Coleoptera

The ash-gray blister beetle is dark to light ashy gray in color. The Striped Blister Beetle is Black and yellow in color, normally with 2 black spots on the head. and two black stripes on the thorax. Each elytra (Hard front wing of most beetles ) has  two to three black stripes. The blister beetle adult is distinguished by the long cylindrical soft body, with the tip of the abdomen extending beyond the end of the wing covers, they also have chewing mouthparts, and a thorax (neck) narrower than both the head and the abdomen. They range in size from 1/4 inch to 1 3/4 inches.

Their range covers most of the United States and they are considered common. They typically feed on garden plants. And many of you may have noticed them feeding on garden vegetables an grasses as well as on ornamental plants like Hostas.

The substance that is excreted from these beetles come from a chemical cocktail comparable to cyanide and strychnine in toxicity. It leaves their body in a "blood" that is released from their legs when disturbed. This toxin is called Cantharidin.  Horses are especially susceptible to the chemical these beetles release. It is estimated that 80 of these beetles (even dead) could kill a horse weighing 900 lbs.

These most unusual and toxic creatures serve us well.  The female deposits her eggs in the soil.  Then these hatch, the larva feed on grasshopper egg pods. So you see, without these little bombshells we would be overrun with grasshoppers! So I encourage when you see these interesting and beautiful insects look but don't touch!

(Story and photos by Shelly Cox, FOLNC Volunteer)