Bug FAQBlue Shield Bug
Zicrona caerulea · Order: Hemiptera · Family: Pentatomidae
Also called: Blue Bug, Blue Shieldbug
The blue shield bug is a small true bug about 5 to 8 mm long with a metallic blue-green body; immature bugs have a red abdomen with black markings. The species is a predator of leaf beetles, beetle larvae and moth caterpillars but also feeds on plants.
Source: Wikipedia
How to recognize it
Adults are uniformly metallic blue-green, while immature bugs have a red abdomen with black markings.
Source: Wikipedia
Size
Adults reach about 5 to 8 mm in length.
Source: Wikipedia
What it eats
It preys on leaf beetles of the genus Altica, various beetle larvae and moth caterpillars, and it also consumes plant material.
Source: Wikipedia
Life cycle
Eggs are laid in spring; the species has one generation per year, with new adults appearing from July onward. Adults survive the winter and are the overwintering stage.
Source: Wikipedia
When you see it
New adults can be found from July onward.
Source: Wikipedia
Where it comes from
The bug occurs in Eurasia and North America.
Source: Wikipedia
Where it is found in the US
Recorded in 11 of 51 states and DC. Most records: California, Nevada, New Mexico, Alaska, Colorado, Texas, Utah, Oklahoma.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What does the blue shield bug eat?
It hunts leaf beetles, beetle larvae and moth caterpillars, and it also feeds on plants.
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/Zicrona_caerulea
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.