Bug FAQAnt bug
Alydus calcaratus · Order: Hemiptera · Family: Alydidae
Alydus calcaratus is a large, 10 to 12 mm, oblong bug that is mostly black with a bright orange patch on the abdomen that can be seen in flight. Both adults and nymphs feed on fallen legume seeds such as Sarothamnus, Cytisus, Genista and Ulex, and have also been seen feeding on carrion and faeces.
Source: Wikipedia
How to recognize it
The bug’s body is blackish and the abdomen shows a bright orange patch that is visible only while flying. Male hind-leg femora are thickened and bear several strong spines on the underside.
Source: Wikipedia
Size
Adults are large for a bug, measuring about 10 to 12 mm in length and have an oblong shape.
Source: Wikipedia
What it eats
Both adults and nymphs mainly eat fallen seeds of legumes such as Sarothamnus, Cytisus, Genista and Ulex. They have also been observed feeding on vertebrate carrion and faeces.
Source: Wikipedia
Life cycle
Mating occurs from July to September, with nymphs present from May to August. Adults appear from late June, are most common in early August to mid-September, and can be seen until October.
Source: Wikipedia
When you see it
In Germany adults are first seen in late June, peak in early August to mid-September, and disappear by October.
Source: Wikipedia
Where it comes from
In North America it ranges from Alaska and Quebec across the United States to Wyoming. Its Holarctic distribution includes the British Isles and most of Europe extending to eastern Siberia and China.
Source: Wikipedia
Where it is found in the US
Recorded in 7 of 51 states and DC. Most records: Colorado, Alaska, Washington, Idaho, Montana, New Mexico, Pennsylvania.
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
Questions people ask
What does Alydus calcaratus look like?
It is a large (10 to 12 mm) oblong bug that is mostly black with a bright orange patch on the abdomen visible in flight, and males have thickened hind-leg femora with strong underside spines.
Source: Wikipedia
What does this bug eat?
It feeds mainly on fallen seeds of legume plants such as Sarothamnus, Cytisus, Genista and Ulex, and it has also been seen feeding on carrion and faeces.
Source: Wikipedia
Same family (Alydidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Alydus_calcaratus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.