10 Fascinating Facts About Stink Bugs

Interesting Behaviors and Traits of Stink Bugs

Harlequin stink bug.
The brilliantly colored harlequin stink bug. Whitney Cranshaw, Colorado State University, Bugwood.org

Stink bugs aren't particularly beloved bugs, but that doesn't mean they aren't interesting insects. Take a few minutes to learn more about their natural history and unusual behaviors, and see if you agree. Here are 10 fascinating facts about stink bugs.

1. Stink bugs do, indeed, stink.

Yes, it's true, stink bugs stink. When a stink bug feels threatened, it releases a pungent substance from special glands on its last thoracic segment, repelling nearly any predator that has a sense of smell (or functioning chemoreceptors).

If you want a demonstration of this insect's infamous skill, give a stink bug a gentle squeeze between your fingers, holding it along its sides. Before you condemn stink bugs for their pungent habit, you should know that all kinds of insects put up a stink when disturbed, including those well-loved ladybugs.

2. Some stink bugs help control pests.

Though most stink bugs are plant feeders and many are significant agricultural pests, not all stink bugs are "bad." Stink bugs in the subfamily Asopinae are predators of other insects, and play an important role in keeping plant pests under control. The spined soldier bug (Podisus maculiventris) is easy to identify thanks to the prominent points or spines extending from its "shoulders." Welcome this beneficial predator into your garden, where it will feed on leaf beetle larvae, caterpillars, and other problem pests.

3. Stink bugs are really bugs.

Taxonomically speaking, that is.

The word bug is often used as a nickname for insects in general, and even for non-insect arthropods like spiders, centipedes, and millipedes. But any entomologist will tell you that the term bug actually refers to members of a specific order or group of insects – the Order Hemiptera. These insects are properly known as true bugs, and the group includes all manner of bugs, from bed bugs to plant bugs to stink bugs.

4. Some stink bug mothers (and a few fathers) guard their young.

Some species of stink bugs exhibit parental care of their offspring. The stink bug mother will stand guard over her cluster of eggs, aggressively defending them from predators and acting as a shield to dissuade parasitic wasps from attempting to lay eggs in them. She'll usually stick around after her nymphs hatch, too, at least for the first instar. A recent study noted two stink bug species in which the fathers guarded the eggs, a decidedly unusual behavior for male insects.

5. Stink bugs belong to the family Pentatomidae, meaning five parts.

William Elford Leach chose the name Pentatomidae for the stink bug family in 1815. The word derives from the Greek pente, meaning five, and tomos, meaning sections or cuttings. There's some disagreement today about whether Leach was referring to the stink bug's 5-segmented antennae, or to the 5 sides of its shield-shaped body. But whether or not we know Leach's original intent, you now know two of the traits that will help you identify a stink bug.
 

6. A stink bug's worst enemy is a tiny, parasitic wasp.

Though stink bugs are fairly good at repelling predators with the sheer force of their stink, this defensive strategy doesn't do much good when it comes to deterring parasitic wasps.

There are all kinds of teeny wasps that love to lay their eggs in stink bug eggs. The wasp young parasitize the stink bug eggs, which never hatch. A single adult wasp can parasitize several hundred stink bug eggs. Studies show that egg mortality can reach well over 80% when egg parasitoids are present. The good news (for farmers, not for stink bugs) is that parasitic wasps can be used as effective biocontrols for pest stink bug species.

7. Stink bug sex isn't particularly romantic.

Stink bug males aren't the most romantic blokes. A courting stink bug male will touch the female with his antennae, working his way to her nether end. Sometimes, he'll head butt her a little to get her attention. If she's willing, she'll lift her hind end a bit to show her interest. If she isn't receptive to his overture, the male may use his head to push her bum up, but he risks being kicked in the head if she really doesn't like him.

Stink bug mating occurs in an end-to-end position, and can last for hours. During this time, the female often drags the male around behind her as she continues to feed.

8. Some stink bugs are brilliantly colored.

While many stink bugs are masters of disguise camouflaged in shades of green or brown, many some bugs are quite flamboyant and showy. If you love to photograph colorful insects, look for the harlequin bug (Murgantia histrionica) in its vibrant orange, black, and white costume. Another beauty is the two-spotted stink bug (Perillus bioculatus), wearing the familiar red and black warning colors with unusual flair. For a subtler but equally stunning specimen, try a red-shouldered stink bug (Thyanta spp.), with its faint rosy stripe along the top of the scutellum.

9. Young stink bugs suck on their eggshells after hatching.

When they first hatch from their barrel-shaped eggs, stink bug nymphs remain huddled together around the broken eggshells. Scientists believe these first instar nymphs suck on secretions on the eggshells to acquire needed gut symbionts. A study of this behavior in the Japanese common plataspid stinkbug (Megacopta punctatissima) revealed that these symbionts affect nymph behavior. Young stink bugs that didn't get adequate symbionts after hatching tended to wander away from the group.

10. Stink bug nymphs are gregarious (at first).

Stink bug nymphs usually remain gregarious for a short period of time after hatching, as they begin to feed and molt. You can still find third instar nymphs hanging out together on their favorite host plant, but by the fourth instar, they usually disperse.

Sources:

  • Stink Bugs, by Blake Newton, University of Kentucky Entomology Department. Accessed online February 6, 2015.
  • Kaufman Field Guide to Insects of North America, by Eric R. Eaton and Kenn Kaufman.
  • Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.
  • Encyclopedia of Entomology, 2nd edition, edited by John L. Capinera.