School of Life Sciences | Ask A Biologist

dropdown arrow downdropdown arrow upshow/hide menu

Ask A Biologist heading
beetles subheader image

Life Cycle

show/hide words to know

  • Eclose: to change from the pupal form into the adult form.
  • Larva: the second, "worm-like" stage in the life cycle of insects that undergo complete metamorphosis (like caterpillars).
  • Metamorphosis: dramatic change in body form... more
  • Moult: shedding of the skin so the animal can grow.
  • Pupa: resting stage during which tissues are reorganized from larval form to adult form. The pupa is the third body form in the life cycle of insects that undergo complete metamorphosis (like caterpillars).
  • Pupate: to change from the larval form into the pupal form.

Beetle Life Cycle

Larvae

Mealworm beetles are very different from humans in how they grow up. They pass through 4 different body forms in their complete life cycle. This is called complete metamorphosis.  As we have seen, the first form is the egg. A beetle remains as an egg for 7 to 10 days before hatching into the second form, the larva. This is the body form responsible for the meal"worm's" name. They are very tiny when they first hatch, and it takes them about 3 months before they enter the next body form. During this time, the larvae eat and eat and grow. However, to grow, they must shed their skin every so often. Right after they molt, their skin is white and soft, which allows the animal to grow before their skins hardens and turns tan again in a day or two.

Larvae molt about 15 times and can get very big. Large larvae are what people buy in pet stores or bait shops to feed their reptiles or fish.

large larvae  pupae

When a larva has eaten enough food and grow big enough, it pupates into the third body form, the pupa.  While in this form, the beetle does not eat or move very much. The pupa just sits and waits while its insides rearrange into the form needed for the fourth and final body stage. The pupal stage lasts for 7 to 10 days, and finally the pupa ecloses and becomes an adult.

The adult form is what we typically think of as a "beetle." In the final body form, beetles look for other mealworm beetles to mate with and produce offspring to start the life cycle over again.

Tenebrio molitor pupa

After the larval stage beetles enters into a third, pupal, stage.

Share to Google Classroom

Be part of Ask A Biologist

by volunteering, or simply sending us feedback on the site. Scientists, teachers, writers, illustrators, and translators are all important to the program. If you are interested in helping with the website we have a Volunteer page to get the process started.

dropdown arrow downdropdown arrow up  Learn More

Tenebrio molitor pupa

After the larval stage beetles enters into a third, pupal, stage.

Share to Google Classroom

Be part of Ask A Biologist

by volunteering, or simply sending us feedback on the site. Scientists, teachers, writers, illustrators, and translators are all important to the program. If you are interested in helping with the website we have a Volunteer page to get the process started.