Life Of A Mealworm

The life cycle of a mealworm (Tenebrio molitor) consists of four stages. Egg, larva, pupa, and beetle.

The darkling beetle goes through full metamorphosis or holometabolous metamorphosis.

Egg stage

Mealworm eggs are very small and usually laid in clusters. The eggs are greyish white and they are 1-2mm in size. The eggs hatch out in 6-8 days at 80 degrees Fahrenheit. The colder it is the longer it will take to hatch.

Larva stage

After hatching the larva are visible within a week. They are white when they hatch and quickly become golden-yellow. From newly hatched to large size only takes 8-10 weeks at 80 Fahrenheit. If you wish to slow the growth rate of your mealworms down simply keep them at cooler temperatures.

During the Larva or "mealworm" stage, the mealworm will molt or shed its exoskeleton skin to grow larger. A mealworm will "molt" 9 -20 times depending on temperature. You can identify a freshly molted larva as it will be white in color. When the larva is about to enter the pupa stage it will curl up into a c-shape making it easy to identify.

The darkling beetle larva can be used for a variety of things such as live pet food for reptiles and other small animals. They can also attract wild birds. Or maybe you would prefer to use them as fish bait. Some cultures even use them for human consumption. A main coarse full of protein followed by dessert. You can eat them in candy or have them covered in chocolate.

Pupa stage

After your mealworms reach large size they will start to turn into pupa. When they are in the pupa stage they will not eat or drink. If you touch them they will wiggle around! They will stay in this stage for roughly 7 days if kept at 80 degrees Fahrenheit. They are creamy white and are between 1/2"-3/4" in size. If the pupa turn black they are dead and can be disposed of.

Beetles stage

When the beetles emerge they are white and will darken over the next few days until they become black and mature. Beetles will begin to mate and lay eggs within 4-6 days after emerging from the pupa stage. Beetles live between 8-12 weeks if kept at optimal conditions.

A female beetle will lay anywhere between 250 - 500 eggs in her lifetime.

Although they do have wings they do not use them unless under great stress.