One very endearing trait (I think) of milkweed tussock moth caterpillars is that they are gregarious through the third instar. A Monarch butterfly delicately perched on a vibrant echinacea flower.

It turns out that monarch caterpillars can be cannibals. They are very hungry , especially after the 3rd instar, so if food is scarce they will eat each other. In this case food was not scarce ...

The third instar larva has more distinct bands, particularly on the abdomen. The fourth instar is characterized by a new banding pattern on the thorax, and white spots on the prolegs near the back of ...

As the caterpillar grows, it goes through five stages, known as instars, shedding its skin each time to accommodate its growing body. During the first instar, the tiny caterpillar first feeds on the ...

Late instar monarch caterpillars sabotage milkweed to acquire toxins, not to disarm plant defence. Proceedings of the Royal Society B . Vol. 291, February 21, 2024.

For example, when a caterpillar hatches from an egg, it is in its first instar. Because caterpillars are gregarious, they often congregate on a single milkweed plant and strip it bare before ...