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Bug of the Week: Stink Bug

Spring is about to burst forth here and more insects are starting to appear again.

Take this stink bug, for example. It wandered up out of the foliage while I was watering.

How do I know it is a stink bug, family Pentatomidae? First of all, it has a wide, flat back that is shaped like an old-fashioned shield. That is why another common name for this group is "shield bug." I know it is a bug because of the triangular-shaped piece in the middle of its back, called a scutellum.

Why are they called stink bugs? Many members of the Order Hemiptera release a distinctive odors from special glands whenever they are disturbed. Some of the odors, but not all, are unpleasant. This one never produced an odor while I was watching it.

As a group, stink bugs are unusual because some are plant feeders and others are predators of insects. How do you tell which one you have? If you are an experienced entomologist you will check the proboscis, or straw-like mouthparts. The plant feeding types have a thinner, more flexible proboscis.

The fact it is feeding on the lettuce I offered it is another big clue. πŸ™‚

Check out the cool illustration of stink bug anatomy I found:


(It is by Giancarlodessi at Wikimedia)

A: head; B: thorax; C: abdomen.
1: claws; 2: tarsus; 3: tibia; 4: femur; 8: compound eye; 9: antenna; 10: clypeus; 23: laterotergites; 25: pronotum; 26: scutellum; 27: clavus; 28: corium; 29: embolium; 30: membrane.

(27-30 represent parts of the wing)

Stink bugs aren't the prettiest insects in the world, but don't you think they are more interesting once you get to know them?

10 thoughts on “Bug of the Week: Stink Bug

  1. Pam

    Wanted a diagram or pointers to the "strawlike" mouth parts for this novice! Think i identified a shield bug just by chance the other day...and and came across this site to verify it. But would love to see the difference between insect feeder proboscis and vegetable feeding proboscis. Thanks!

  2. Roberta

    Pam, that is a good idea, to show the differences side by side. I'm afraid I don't have anything like that right now. One way to tell is to offer the bug something to eat, like lettuce and a caterpillar. You will know at once which one it prefers.

  3. Mark

    I found a Marrmorated Brown Stink Bug today (22 Feb 2015) in my sink feeding on a slice of leftover cooked carrot. Could clearly see the proboscis. It stayed there for over an hour. It was very interesting to watch.πŸ”¬πŸ‘ Just hope no relatives see it cause they will think I am loony for not just gettingrid of them!

  4. Jeanne Coppola (no website)

    I found your website when I was searching for photos of shield bugs, to identify the one I found on a newspaper vending machine, by the bus stop. I want to keep it and feed it, and want to find out what kind it is. I found other photos of shield bugs that look like mine, and one site said it eats birch leaves. Now I have to go back to the bus stop and get some leaves. I gave him lettuce, but I do not know if he is eating it. I will give him some cooked carrot, sine I have carrots at home!!! I try to save insects, and seem to find them. Last summer I found a grasshopper with a missing leg on the side of a building in a busy shopping area. I took him home (in a small cup), and he lived for months, into January. I kept hm in a plastic food container with twigs and a screen taped over a square hole in the top. I fed him lettuce every day (he liked romaine lettuce, and he ate the thin light green leaves, not the dark ones), and I sprayed water in the container every day, in the corner on top of the lettuce.

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