Book 16, Question 47
Why Do Some Desert Insects Have Waxy Skin?
Insects lose water through their outer shell, and in a dry place that can be a big problem! Many desert beetles and ants have a waxy layer on the outside. It works like a raincoat in reverse, keeping water inside.
More fun facts
- Insects are small and have lots of skin surface for their size, so they could dry out quickly in the heat.
- Even so, thousands of kinds of insects live in the hottest, driest places on Earth.
- Much of their success comes from an outer covering, called a cuticle, that hardly lets water through.
- The main water barrier is a thin layer of waxy, oily substances on the very outside of the cuticle.
- Scientists found that when this waxy layer gets hot enough to melt, water escapes through the cuticle much faster.
- A desert darkling beetle called Cryptoglossa verrucosa grows tiny threads of wax from little bumps on its shell.
- In very dry air, the wax threads build up and turn the beetle light blue, but in damp air it looks jet black.
- The wax web cuts water loss and may help reflect sunlight, so the beetle warms up more slowly.
Sources: Csulb, europepmc.org
Questions kids ask
How else do desert insects avoid drying out?
Many also use their behavior, steering clear of the hottest and driest conditions.