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 ...

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 ...

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.

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 ...

The only thing monarch butterfly caterpillars eat is milkweed, and researchers say mowing down a third of that milkweed will attract more eggs ...

WASHINGTON— The annual overwintering count of monarch butterflies released today confirms butterfly numbers fell by nearly one-third from last year's count, indicating an ongoing risk of extinction ...

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