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How to Identify Cocoons of the Southwest

Is it a dried up leaf, a pebble or a cocoon? Or is it a butterfly's chrysalis? Identifying cocoons in the deserts, chaparral and mountains of the Southwest can be challenging but rewarding. If you're on a quest to track down a specific species or simply out to have some fun, detecting these small, delicate objects definitely takes a keen eye and some patience. But if you're lucky, who knows--you may find enough abandoned cocoons to make a rattle. That's what Native Americans such as the Miwoks did for the rattles that were an essential part of their healing and dancing ceremonies.

Instructions

- 1
  
  A monarch caterpillar makes a chrysalis.
  
  Examine the color and texture of the cocoon to make sure it's not a chrysalis. The term cocoon is used incorrectly sometimes in reference to the pupa of a butterfly. Only moths make cocoons. A chrysalis may be metallic gold or, as in the case of the monarch caterpillar, green, so that it blends in with its host plant. A cocoon, on the other hand, is typically brown and may be spun from silvery silk or formed from a tough, papery substance.
- 2
  
  The Juno buckmoth favors the mesquite of the American Southwest.
  
  Find the right flora. Caterpillars, and the moths they become, favor certain host plants. For instance, the white-streaked saturnia moth, local to California and Mexico, favors buckbrush and mountain mahogany, among others. The Juno buckmoth likes the mesquite of East Texas, New Mexico and Arizona. The yucca moth, which ranges from the Southwest into Mexico, is by far the easiest to identify. Where there's yucca there's the yucca moth. Its larvae feed solely on yucca seeds, while the plant depends exclusively on the transformed moth to pollinate its flowers.
- 3
  
  Yucca moth cocoons may be found only near yucca plants.
  
  Look down. Not all cocoons cling to a stem or leaf. After hatching, a yucca moth larva forms a silvery subterranean cocoon made of silk no more than half an inch long. Grains of desert sand coat the typically round pod for protection. You will see these cocoons in the winter. When spring comes the small white moths hatch in time to pollinate the yucca's flowers. The larva of the big poplar sphinx moth, which lives all over the Southwest, also burrows into the ground when it's time to pupate.
- 4
  
  Is there a cocoon among those leaves?
  
  Investigate leaves. The Io moth, found in many parts of the United States, including Texas, New Mexico and Colorado, is partial to Texas sugarberry and oak. Its larva attaches to one of the leaves that typically covers the ground at the foot of a tree and forms a delicate silken cocoon; or it may attach to a living leaf, which then dies, turns brown and falls, taking the cocoon with it. Either way it ends up on the ground. So what may look like a small dried up leaf littering the earth may actually be a cocoon.

Insects & Science