Bug FAQSmall Milkweed Bug
Lygaeus kalmii · Order: Hemiptera · Family: Lygaeidae
Also called: Common Milkweed Bug, Small Milkweed Bug Complex
Adults are orange-red with gray or black markings and measure about 10 to 12 mm long (0.39 to 0.47 in). They feed mainly on flower nectar and milkweed seeds, but will eat other insects if those foods are scarce. They are found across Central and North America in temperate regions and do not migrate.
Source: Wikipedia
How to recognize it
Young bugs start fully red and later develop black diagonal marks on the pronotum. The head is black with a central red spot; the forewings show a black heart inside an orange-red X that does not meet in the middle.
Source: Wikipedia
Size
Adults are 10 to 12 mm (0.39 to 0.47 in) long.
Source: Wikipedia
Where it lives
They live in north-temperate parts of North America and are not migratory.
Source: Wikipedia
What it eats
They obtain nutrients mainly from flower nectar and milkweed seeds. When those sources are limited, they may also feed on other insects.
Source: Wikipedia
Life cycle
Only adults survive the winter and they start reproducing the following April. In spring they lay eggs on milkweed plants (Asclepias spp.).
Source: Wikipedia
When you see it
Females are receptive to males throughout the year.
Source: Wikipedia
Where it comes from
Their range includes Central and North America.
Source: Wikipedia
Lookalikes
It is often mistaken for other red-and-black bugs such as Oncopeltus fasciatus, Lygaeus turcicus, and Lygaeus reclivatus.
Source: Wikipedia
Where it is found in the US
Recorded in 49 of 51 states and DC. Most records: California, Texas, New York, Colorado, Massachusetts, Arizona, Michigan, Pennsylvania.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Same family (Lygaeidae)
Large Milkweed BugOncopeltus fasciatus
False Milkweed BugLygaeus turcicus
Indian Milkweed BugSpilostethus pandurusDamages trees, gardens or crops
Black-and-Red BugLygaeus equestris
Harlequin bugSpilostethus saxatilisDamages trees, gardens or crops
Darth Maul BugSpilostethus hospesDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Lygaeus_kalmii
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.