Who Else Eats Milkweed?

Just in case you were operating under the assumption that the only thing that eats milkweed is the monarch butterfly caterpillar there is this. 

click on images for a closer look

 

Gross - eh?

Meet Euchaetes egle - the milkweed tussock caterpillar or milkweed tiger moth.  I found a swarm of these voraciously feasting-upon a milkweed plant literally skeletonizing it as they chomped their way along. 











Belonging to the family Erebidae this is a common mid-summer caterpillar that feeds-upon milkweed and dogbane.  Like most other critters that dine on milkweed the cardiac glycosides concentrate in their bodies endowing them with a chemical defense against predators.   While the caterpillars of this tiger moth are adorned with a vivid orange and black (like the monarch butterfly) birds learn to avoid the larva. 

However, the adult is a drab brown moth lacking any coloration signaling its toxicity.   As a consequence the adult moth has evolved an organ that emits an ultrasonic signal easily detected by bats.   Who quickly learn to avoid the tiger moth as a meal.

photo - Wikipedia