Bug FAQGiant Mealworm Beetle
Zophobas atratus · Order: Coleoptera · Family: Tenebrionidae
Also called: Darkling beetle, King Worm Beetle, Morio Worm Beetle, Superworm Beetle
Source: Wikipedia
The larvae grow to about 5 to 6 cm long and have dark, almost black ends, making them look like very large mealworms. They are native to tropical Central and South America and are often bred as high-protein feed for reptiles, amphibians, fish and birds. When handled they may bite, though the bite causes only mild discomfort.
Source: Wikipedia
Size
Full-size larvae are about 50 to 60 mm (2.0 to 2.4 in) long.
Source: Wikipedia
Can it bite, sting or make you sick?
When threatened by handling they may bite, though the bite is not very painful.
Source: Wikipedia
Where it lives
They can be easily contained, making them ideal for breeding as feed for captive insectivores.
Source: Wikipedia
What it eats
The larvae are relatively high in protein and fat and are used as pet feed for many insectivores. When fed a polystyrene diet they stay more active and gain a slight amount of weight compared with starving larvae.
Source: Wikipedia
Life cycle
Mature larvae become stiff and curl into a “C” shape to pupate. Adults emerge 1 to 3 weeks later, initially white to light brown and later darkening to black.
Source: Wikipedia
Lookalikes
They look like very large mealworms, but the darkened ends help tell them apart.
Source: Wikipedia
Where it is found in the US
Recorded in 30 of 51 states and DC. Most records: Florida, Texas, California, New York, Pennsylvania, North Carolina, Illinois, Ohio.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
How big do Giant Mealworm Beetle larvae get?
They grow to about 5 to 6 cm (2.0 to 2.4 in) in length.
Source: Wikipedia
Do they bite?
Yes, they can bite when threatened, but the bite is only mildly painful.
Source: Wikipedia
What do they eat?
The larvae are high-protein, high-fat feeders used as food for reptiles, amphibians, fish and birds, and they can even gain weight on a polystyrene diet.
Source: Wikipedia
Where are Giant Mealworm Beetles from?
They are native to tropical Central and South America.
Source: Wikipedia
Same family (Tenebrionidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Zophobas_atratus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.