Stink Bugs

by Michael Holmes

Though people commonly refer to all insects as bugs, entomologically the term is reserved for a specific group of insects called "true bugs". These insects have characteristic needle-like mouthparts that stab and suck the liquefied contents from other organisms like a straw. They form a large order of insects called Hemiptera, which includes a particularly pungent bunch of bugs:

Coming in a range of colours and patterns, the shield-shaped stink bugs can be quite an attractive lot of insects. Unfortunately for us (but fortunately for them), they stink!

Possessing potent scent glands beneath their thorax, stink bugs discharge their foul-smelling chemicals to deter potential predators or signal fellow bugs. If you have ever mishandled or otherwise disturbed a stink bug, you may have caught a wiff of their distinct odour.

Some stink bugs prey on other insects, but many feed on sap, extracted from plants through their specialized mouthparts. The inside of their long, narrow beak is divided into two tubes. One tube injects saliva into its food, liquefying the contents. The adjacent tube sucks up the mushy meal. When not in use, they tuck their mouthparts down beneath their heads. If you look closely at the underside of a stink bug you should be able to see this needle-like appendage.

Female stink bugs make devoted mothers, guarding her eggs until they hatch then watching over the nymphs until they molt and are ready to face the world on their own. This maternal care gives her young a good start in life, when otherwise they might become an easy meal for predators.

There is a wide variety of stink bugs, though the most common species are either brown or green in colour. The Banasa Stink Bug (Banasa dimidiate) is a brilliant green bug with brown markings on its back, commonly found feeding on berries and seeds. Podisus serieventris is brown with heavily speckled legs.

If you are out in the garden, keep an eye (and nostril) open for these exceptionally aromatic bugs. They might be right under your nose.