When they first hatch, monarch caterpillars are only about 2 millimeters long. For tiny critters, the world is a dangerous place. Watch a freshly hatched caterpillar deal with two hazards...
In the video, you can see a tiny caterpillar, about 2 mm in length, dealing with two hazards...
- Tiny hairs attached the underside of the leaf are called trichomes. These create a tangle or barrier to eating and moving about. Caterpillars have to spend time and energy shaving away the trichomes before they can feed.
- The sticky and toxic sap, pressurized in the veins of the leaf, is ready to pop out and entrap the caterpillar. To exclude sap from the area where it is feeding, the caterpillars cuts a crescent-shaped "moat" around its feeding spot.
- The caterpillar recoils when white sap suddenly wells out.
- In an area next to the "moat," the trichomes have been shaved away, giving the caterpillar access to the leaf tissue.
- Moving down from the new sap drop, the caterpillar relocates to eat on the edge of the leaf, in an area where the sap is less likely to flow because of the crescent cut by the caterpillar.