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, but ...

Instead of nipping milkweed to drain the plants’ defensive sap, older monarch caterpillars may seek the toxic sap. Lab larvae guzzled it from a pipette.

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 ...

The second instar larva develops a characteristic pattern of white, yellow and black transverse bands, and the tentacles start to grow. The third instar larva has more distinct bands, particularly on ...

Butterflies fluttered through the flower-laden Via Italia heritage garden Sunday afternoon as wide-eyed children and adults looked on during the 3rd Annual Monarch Butterfly Festival. The newly ...

"I planted a bunch of milkweed for the migrating monarch butterflies, but there’s a fuzzy orange, black and white caterpillar eating my milkweed. What should I do?" — P.R.

One very endearing trait (I think) of milkweed tussock moth caterpillars is that they are gregarious through the third instar.