Unique is the egg batch of the map butterfly. It forms small egg turrets on the bottom side of stinging nettle. From every one of these eggs a small caterpillar hatches within a few days. egg turrets of the map butterfly, Araschnia levana
When the time has come, and all nutrients of the egg are depleted, the caterpillar must leave its egg. Hatching is a difficult process. It starts with positioning the small caterpillar in the right spot. The picture below shows a gypsy moth caterpillar just before hatching. The egg is surrounded by light brown setae-covered masses, which is laid by the butterfly between the eggs to protect them.

gypsy moth caterpillar, Lymantria dispar, before hatching
map butterfly caterpillar before hatching

After positioning itself, the caterpillar begins to bite through the eggshell with its mandible, the caterpillar's mouthpart for biting. The arrow on the right picture marks the mandible.

Hatching´s quite a hard job, may take several hours and will be interrupted frequently
- in particular when the caterpillar is disturbed.

mouthpart with mandible of gypsy moth

Once its head is completely outside, the work is almost done.The first action the freshly hatched caterpillar undertakes,
hatching caterpillar of the map butterfly is to devour its eggshell. thus exploiting this valuable substance. Nature is very economic!

© Onview.net Ltd, Microscopy-UK, and all contributors 1995 onwards. All rights reserved. Main site is at www.microscopy-uk.org.uk with full mirror at www.microscopy-uk.net.