Diseases, Defects, and Injuries of Butterflies

In nature, butterflies with defects soon become part of the food chain. When raising caterpillars and butterflies inside an enclosed area, injuries and disease can be observed first hand.  Some of the problems a caterpillar may encounter are bacterial diseases, defects during development, or falling before the butterflies wings are completely dry. Watching a butterfly struggle as it tries to overcome its impairment is saddening. I have also learned that in the wild the survival rate of an egg making it to a butterfly is less than 10%! By rearing caterpillars in captivity this can be reversed so that up to 90% can survive to be butterflies. 

Bacterial Infections

Active caterpillars crawled over my soft chrysalises causing punctures.

Raising caterpillars in captivity has many benefits, but it has disadvantages as well.  I have had as many as forty caterpillars in one container. The result was that the active caterpillars began to crawl over the soft chrysalises before they hardened resulting in damage. Some chrysalises became disfigured or got punctured allowing unwanted bacteria to enter. Also, the abundance of waste was difficult to manage. One way to overcome this problem is to gently remove the caterpillars before they make a chrysalis. The finding of this experiment was that the maximum of 20 caterpillars per my 12” x 8” container is the most effective way to prevent overcrowding problems.

For the sake of my readers and completion of my research on defects, I decided to open one of the punctured chrysalis effected by overcrowding. With the help of tweezers, I gently removed the thin chrysalis covering. My discovery was that bacteria had entered and began to eat away at the once developing butterfly. The butterfly was dark brown, and mushy. Its antennae, eyes, proboscis, wings, and abdomen were packed neatly inside. It proboscis was still two separate pieces instead of one long tube. Looking inside was unpleasant, but I learned what the effect is of bacteria attacking a chrysalis.

 

Finding bacterial infections in chrysalises is an unpleasant subject, but it is part of raising butterflies. The Monarch above did not have a puncture in the chrysalis. The bacteria must of been acquired as a caterpillar. Rain and damp weather can have this effect and result in a black mushy chrysalis. Infected chrysalises should be removed and disposed of properly. I put mine in a sealed container and put it inside the freezer before getting rid of it.

Wing Damage of Fallen Butterflies

 

Butterflies have soft wings when they first emerge. Loosing their grip as they are hanging to dry can be fatal. They quickly are snatched by a lizard, bird, or other creatures. Raising butterflies in an enclosed area gives you more control. If the fallen butterfly has minimal damage, it can be safely transferred to an object to finish drying. Most of the time the butterfly is found too late. This Gulf Fritillary above fell resulting in damaged wings.

This is my first deformed Monarch butterfly we named “Ed”. It emerged April 16, 2009 when my journey with butterflies was just beginning. In my journal, I found the pages where I logged its life.  I fed it banana, pineapple, and honey water. “Ed” lived one week because I fed and cared for him. “Ed” was unable to fly because of its injury. Even though a butterfly is damaged, my experiment shows that a damaged butterfly can survive at least a week in captivity.

Defects During Development

Some deformities are genetic. They take place inside the chrysalis during it’s development. This Gulf Fritillary butterfly emerged with one deformed antennae and a short split proboscis.

This Polydamas Swallowtail’s wings did not develop correctly. Its hindwings and forewings are too small for flight.  It will not survive.

Problems can arise as the caterpillar is going through its last molt to become a chrysalis. This Gulf Fritillary caterpillar head capsule did not shed off during the molting process. It died at this stage.

These are just some of the defects I have observed while raising butterflies.

My Costa Rica tour is in 22 days.

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