Thursday, March 29, 2012

Giant Brazilian Cockroaches

Several alert staff members have pointed out that one of the Giant Brazilian cockroaches has crumpled wings. Life Sciences staff is aware of this. Although we can’t fix the wings, we do not consider the animal to be in distress. But it does bring up some interesting questions about the processes of metamorphosis and insect life cycles.

To review the life cycle of cockroaches, they are among the insects that go through incomplete metamorphosis. Younger insects resemble miniature versions of the adult, except that they lack wings and mature reproductive organs. When they reached full size, they molt for a final time, and become adults with developed wings. After that, they can fly and they can reproduce, but they can never shed their exoskeleton again.

Insects with incomplete metamorphosis can often recover from damage received early in their lives. If a limb is lost, a stubby new one can grow in after the next molt. With each successive molt it becomes closer in size to an undamaged limb, though it will probably never be quite as big. You can see some of our stick insects with regrown limbs. Other arthropods, like crabs, have similar regenerative abilities. However, once the final shed takes place, the insect is no longer able to replace parts

In the case of our crumpled roach, the final shedding process was probably interrupted by something. Perhaps the roach fell, or was stepped on by another insect. Maybe it was feeding time and the roach hurried to eat before drying fully. We don’t know the details, but the end result was that the wings did not dry flat. For an insect living in a secure caged environment, this is not a deal breaker. The roach can get to food and water, and doesn’t seem to have underlying health problems. If you’d like to see it or any of the other Giant Brazilian cockroaches on exhibit, plan a visit to Pacific Science Center’s Insect Village soon!

No comments:

Post a Comment