Mealworms
aren’t really worms. They are the larvae of darkling beetles.A
darkling beetle experiences complete metamorphosis which means that it has four
distinct stages of life namely egg, larva, pupa, and adult. The amount of time
a darkling beetle spends in each stage can vary greatly due to environmental
factors like temperature, humidity, food, and water.
Egg
The first
stage of life is the egg. The white bean-shaped egg is tiny and about the size
of a speck of dust. The egg is sticky and is quickly concealed by dirt, dust,
and substrate. It will take around one to four weeks for an egg to hatch and
the larva to emerge.
Larva
The
second stage lasts about eight to ten weeks and is spent as a brown larva or
better known as the mealworm. When first hatched, it is quite small but will
grow to 2 to 3 cm long. Since it has a hard exoskeleton, the worm will need to
molt and shed its hard outer shell in order to grow. Molts will occur ten to
twenty times during this stage of life. A recently molted worm will be soft and
white, but the exoskeleton will quickly harden.
Pupa
During a
mealworm’s last molt it will turn into a white pupa. It has no mouth so does
not eat. It does have leg and wing buds, but they do not function. The pupa is
quite helpless and the only movement it can do is wiggle. This stage of life
will last 1 to 3 weeks as the pupa transforms its organs and body into an
adult.
Adult
The final
stage of the insect’s life is as the darkling beetle and lasts 1 to 5 months.
The beetle will be white with a soft exoskeleton. As the outer shell hardens,
it will turn brown and then dark brown, almost black. The beetle does have hard
wings, but it is unable to fly.