Yellow mealworm

Adult Tenebrio molitor are large, shiny, dark brown or black beetles between 12 and 18 millimetres long.

Mealworm larvae are white at first, then take on a characteristic yellow color as they mature, reaching about 30 millimeters in length.

Mealworm larvae resist dryness and cold and can survive for up to three weeks at minus 15 degrees Celsius, but they prefer 25 degrees Celsius and moisture.