Bug FAQSpiny Shield Bug
Picromerus bidens · Order: Hemiptera · Family: Pentatomidae
Also called: Stink bug, Spiked Shieldbug, Spined Shieldbug
The spiny shield bug is a large predatory shield bug about 12 to 13.5 mm long with variable brown or bluish colour and two thorn-like projections on the pronotum. It lives in forests, heathland, gardens and flower-rich meadows across the Palaearctic from northern Europe to China and North Africa. Both adults and nymphs hunt other insects but they also sip plant sap; they hatch in spring, become adults by July-August and can be seen until November.
Source: Wikipedia
How to recognize it
Front femurs have a ventral spine at the tip, early nymphs are reddish, later nymphs are grey-black with banded antennae and legs.
Source: Wikipedia
Size
Adults measure about 12 to 13.5 mm in length.
Source: Wikipedia
What it eats
Both adults and nymphs are predatory, feeding on larvae of leaf bugs, beetles, aphids and caterpillars. They also suck sap from plants.
Source: Wikipedia
Life cycle
Females lay eggs on tree trunks and leaves; larvae hatch in spring and undergo five molts to become adults.
Source: Wikipedia
Lookalikes
Picromerus bidens, known as the spiny or spiked shield bug, is a carnivorous member of the Pentatomidae family.
Source: Wikipedia
Where it is found in the US
Recorded in 10 of 51 states and DC. Most records: Vermont, Michigan, New York, Maine, New Hampshire, Massachusetts, Minnesota, Wisconsin.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in North America; introduced in United States; introduced in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do spiny shield bugs eat?
They hunt other insects such as leaf bugs, beetles, aphids and caterpillars, and they also sip plant sap.
Source: Wikipedia
When can I see spiny shield bugs?
Adults appear from July or August and remain visible until November.
Source: Wikipedia
Where do spiny shield bugs live?
They are found in forests, heathland, gardens and flower-rich meadows across a wide Palaearctic range.
Source: Wikipedia
Same family (Pentatomidae)
Brown Marmorated Stink BugHalyomorpha halysDamages trees, gardens or crops
Green Stink BugChinavia hilarisDamages trees, gardens or crops
Harlequin BugMurgantia histrionicaDamages trees, gardens or crops
Brown Stink BugEuschistus servusDamages trees, gardens or crops
Green Shield BugPalomena prasina
European Striped Shield BugGraphosoma italicumSources
- Wikipedia: https://en.wikipedia.org/wiki/Picromerus_bidens
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.