Stink bug with caption "Why do stink bugs stink?"

Why do stink bugs stink?

Why Do Stink Bugs Stink?Since making their grand debut in the United States in 2001, stink bugs have garnered headlines across the nation for spreading like wildfire to at least 38 states. Both a nuisance to home owners and a economic pest to farmers, stink bugs are a real pain these days.

There are thousands of stink bug species found in most parts of the world, primarily Asia. They range in size from 1/4 of an inch to 1/2 of an inch in length and range in color from gray to brown to green or blue, while others are black with orange or red markings. Some species are significant threats to crops such as cotton and cabbage; for example the harlequin cabbage stink bug is particularly destructive to plants in the mustard family. However, the insect is particularly famous first and foremost for its namesake: stinkiness. But why do stink bugs stink?

Stink bugs, also known as shield-bugs due to their shape, rely on their olfactory-assaulting chemicals for protection against predators such as birds, lizards and mice or anything else that may be severely harassing them.

The noxious chemical flows from the two glands on the stink bug’s thorax. The stink bugs glands pack a powerful noxious punch: five to ten micro-liters, nearly five percent of the stink bug’s weight! The odorous one-two roundhouse is usually delivered as a last ditch effort to ward off threats.

What do stink bugs smell like?

“The chemicals that comprise a stink bug’s stink are called aldehydes,” said Nancy Troyano, PhD, training manager, entomologist at Rentokil (Ehrlich). They vary from one stink bug species to the next. Some of the most common aldehydes are described by chemists as fine wine: ‘diffusive orange with floral topknots,’ and ‘citrusy and spicy vegetable.’

Yet, to many people, stink bugs often taste like red-hots candy (cinnamon imperials) or cinnamon gum. Stink bugs are even eaten as snacks in some parts of Mexico, Africa and India. Red wine and cinnamon candy doesn’t seem like such a bad idea!

Why do stink bugs have a smell?

“Stink bugs concentrate these chemicals to the extent that they become toxic to birds and other predators,” said Dr. Bryan Krall, entomologist at Parkland College. Krall also added that the stink bug smell can also kill the stink bug emitting it; if it’s trapped in stoppered vials, or kept in cases without proper ventilation as the noxious chemicals get into their respiratory system and asphyxiate them.

The chemicals also serve as a type of alarm pheromone alerting other stink bugs of imminent danger. The Southern Stink bug, green in color,  relies on its chemical weapon specifically for this purpose as other Southern stink bugs will take heed and high tail it out of harm’s way. The clown beetle, found in the southwestern United States, is often mistaken for a stink bug. The black insect attempts to warn off predators by standing on its head, exposing its defensive glands, and eventually spraying an oily, foul-smelling secretion.

Unlike the aldehydes that stink bugs possess, the clown beetle relies on chemicals called quinones. But a common predator, the grasshopper mouse, has discovered a way to circumvent this defense system. As the clown beetle stands on its head the grasshopper mouse quickly grabs the beetle, planting it, rear-end first, into the sand. The sand absorbs the stink as the beetle is helplessly devoured, head-first, by the mouse. Yikes!

How do I get rid of stink bugs in my house?

Why Do Stink Bugs Stink?
Stink bugs have become a common overwintering pest in the United States.

The brown marmorated stink bug will attempt to gain entry into warmer structures in order to overwinter.  “Avoid using pesticides indoors when trying to control stink bugs,” says Troyano. More harm than good will befall people, especially children as well as pets with indoor pesticide use.

Troyano adds that it’s best to vacuum or sweep them up, tightly seal the bag and then place the bag in an outdoor trash can. It’s also ideal to seal cracks around windows, siding, doors, utility pipes, in short-seal any openings that lead from the outside into the house.

Get to know the eastern United States’ #1 most wanted stink bug – the brown marmorated stink bug.

Have you had any stink bug encounters? Please enlighten us in the comments, or contact us today!

Stephen E. Doyle

I am a Professional Writing major at Penn State University (Berks Campus). I will graduate in May 2014. I have finally decided to pursue my lifelong love of writing via a career change. I am a fulltime college student, fulltime father of two wonderful boys- 8 years and 5 months- and an avid reader of noir fiction, historical fiction and enjoy the occasional biography. I am also a freelance writer enjoying my summer internship with Rentokil (Ehrlich) in Reading, Pennsylvania as a marketing intern primarily writing for the blog sites for Rentokil and Ambius as well as content for the Rentokil (Ehrlich) website. I freelance for The Reading Eagle newspaper (Berks County, Pa) and I write for the Home Builders Association's award winning bi-monthly magazine, 'At Home In Berks'. A few of my hobbies are writing, watching and playing soccer with my 8 year-old son, watching my 8 year-old son play soccer, reading, watching old films (Kurosawa, Melville, Dasin, Wim Wenders, etc.), cooking and weekend jaunts to New York City.

1 Comment

  1. Caellon

    I have had an encounter with a stink bug just yesterday inside my garage. I tried to pick it up to put it outside but it didn’t want to get on my hand. Once I did manage to pick it up, I smelled a strange cilantro like scent and didn’t think it was the stink bug until I inched my nose closer to the bug and my nose was overrun with the smell. I threw the bug outside as far as I could, then I tried to wash the smell off of my hands, but it just wouldn’t come off until I took a shower later that day. That was my encounter with a stink bug.



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