Shield Bug

Some of you might remember last fall, I mentioned I saw a Shield Bug in my house and didn't pick it up and place outside because it saw so cold.  By evening it had moved around to some secret place and I didn't see it again...until yesterday.  There it was out in my garage, clinging to a drapery I had hung several years ago in an attempt to block off a portion of it to make myself a laundry room of sorts.

At first I thought the spot was a hunk of lint, or perhaps a bit of dried mud clinging there, but closer

inspection divulged it a bug...my Shield Bug.  Where has it been all these months?  How has it managed to survive?  Will it still be around come March when I feel I can safely return it to the wild?  What the heck is it eating?  What DO Shield Bugs eat?

Hmmm??? I feel research coming on.  I'll be back.

Okay, here's the scoop.


Shield bugs are mainly phytophagous (feeding on plant sap), though a few are carnivorous and may even be useful in controlling pests. They are often called Stink-Bugs because they can produce a horrible smell. In the adults the noxiously smelling fluid is produced by a pair of glands in the thorax and released via a pair of pits on the metathorax, in the nymphs there are 3 pairs of scent glands in the abdomen and the liquid is released through special openings in between the 3/4, the 4/5 and the 5/6 abdominal segments. The scent does work though and is known to repel certain vertebrate predators, in some species it will strongly stain your fingers like iodine, and the smell gets right up your nose, yuck.

Some Shield Bugs are pests, i.e. the Harlequin bug which is a pest of cabbages, Antestiopsis spp. Which are a pest on coffee and Nezara viridula which is cosmopolitan (found all over the world) and a pest of a wide range of common crops such as tomatoes, beans and cotton. The phytophagous Shield Bugs all have symbiotic bacteria in their guts in order to help them digest the food they eat, the eggs are smeared with an inoculation of these symbionts when laid, which ensures that the young, which eat their eggshell on hatching, have enough of them to digest their next meal.

Now, I realize this is probably more than you ever wanted to know about bugs, and Shield Bugs in particular, but, I have to wonder even more just exactly what my Shield Bug is eating.  Sure, I have a few plants in the house but they are mostly in the sun room, the farthest room from the garage, and I confess I have never seen the bug flying through the house to get to my greenery...besides...I have the back two rooms of the house blocked off with a sheet during the winter so I don't have to heat them, and so their colder air does not invade my warmth.

Still?????  How is this creature surviving.  I checked out a web page for teachers who encourage students to become interested in nature, and the suggestion was to wash a green bean, to provide food for a Shield Bug.  Tee, hee, how odd is that going to be when I order one green bean next time I order groceries.

I'm thinking I just might let things as they are.  It seems we are living in perfect harmony, so why disrupt nature.  I will hope my bug puts in an appearance from time to time, to let me know it is doing okay, while I keep my hope alive I can return it to 'nature' in the next few months.

Shield Bug information from earthlife.net, Gordon's Shield Bug page.