Stink bugs do not possess teeth and are incapable of chewing solid food. Like all true bugs in the order Hemiptera, they are equipped with highly specialized mouthparts designed exclusively for piercing and sucking liquids. This feeding apparatus allows them to access the internal fluids of their food source, which is typically plant matter.
The Stink Bug’s Mouth: A Piercing Rostrum
The external mouthpart of the stink bug is a segmented, straw-like structure known as the rostrum, or sometimes called the proboscis or beak. This structure is typically folded and held securely beneath the insect’s body when it is not actively feeding. The rostrum acts as a protective sheath for the four internal components that perform the actual piercing. Inside the rostrum are four needle-like filaments called stylets. These stylets are modified versions of the insect’s mandibles and maxillae, which in other insects might form chewing jaws. The paired mandibular stylets are on the outside, and the paired maxillary stylets are held together by a tongue-and-groove mechanism to form two internal channels: the food canal used for ingestion and the salivary canal used for injection.
How Stink Bugs Use Their Stylets to Feed
When a stink bug locates a food source, it deploys its rostrum, pressing the tip against the plant surface. The four stylets then emerge from the sheath and are driven into the tissue, penetrating the outer skin of the plant. This piercing action allows the insect to reach the nutrient-rich fluids within the plant cells. Once inserted, the bug injects a watery saliva containing digestive enzymes through the salivary canal.
The enzymes liquefy the plant cells and tissues surrounding the stylet tips. The stink bug then uses strong muscles to pump the pre-digested liquid through the food canal and into its digestive system. This feeding method is particularly damaging to crops like apples, peaches, tomatoes, and soybeans.
Crop Damage
The injection of saliva and removal of cellular contents cause localized tissue death, resulting in sunken, necrotic spots, dimpling, or severe deformities on fruits. A single stink bug can inflict multiple feeding wounds, leading to economic loss.
Do Stink Bugs Bite Humans?
Stink bugs are not aggressive toward humans and do not seek out people or animals as a food source. Their feeding apparatus is adapted to consume plant sap, meaning they have no interest in piercing mammalian skin. Therefore, a purposeful “bite” is virtually nonexistent.
In extremely rare instances, a person who handles a stink bug roughly or traps it against the skin might feel a slight prick. This is not a predatory bite but an accidental, defensive probing with the sharp stylets. Any resulting irritation is minor and temporary. Stink bugs pose no threat of disease transmission to humans or pets.