Now that spring is almost over and summer is slowly making its presence known, I have turned my attention to another interest of mine. While I love collecting adult lepidoptera in the field and appreciating their beauty that way, I also enjoy rearing their caterpillars and documenting them as they progress into their adult stages. I have become increasingly interested in learning how to identify host plants of various species of lepidoptera and what a better way to understand plants than to study the caterpillars that eat them. I have come across many different species of lepidoptera in their caterpillar stages, but it wasn’t until very recently that I have become interested in rearing these creatures myself.


The Hosts With the Most

When it comes to finding and successfully rearing caterpillars, one must need to learn the plants they feed on. Sometimes that can be a specific type of plant such as milkweed for Monarchs, or a wide variety of plants for more generalist feeders such as Hyles lineata (white-lined sphinx moth). That’s why learning the host plants of different species can be very useful when in areas with high plant and insect diversity. Luckily, I have been able to do a lot of “self-study” and now know a number of different host plant species for a variety of both butterflies and moths. The amount of precipitation the northern part of California received this year has also helped in making host plants more abundant for caterpillars to feed on, which in turn makes it easier for me to feed any hungry caterpillars I end up bringing home with me.

Nymphalid caterpillars aggregating on the leaves of a wild thistle species.

After multiple trips to a number of canyons, trails, and parks, I have collected, reared, and released a number of different butterfly species native to California. They were all fairly easy to rear and cuttings of their host plants were easy to obtain, making for a very smooth rearing process. Of the many species that I found, the monarch and variable checkerspot were very easy to rear. Thankfully I had no parasites emerge from the caterpillars or chrysalises, which can be common among many butterfly species when collected as caterpillars in the field. This is also true for many larger moth species such as silk moths (Saturniidae) and sphinx moths (Sphingidae) and is very common in species like the woolly bear moth (Family: Erebidae). While these occurrences do happen, most of the time a caterpillar that is collected in the field will be able to continue its life cycle into an adult.

Despite the chance of having something other than a butterfly emerge from these chrysalises, I reared the caterpillars out and was lucky enough to have all of them make it to their adult stages. Once all my butterflies emerged, I decided to keep a few for my collection and release the rest back into their respective habitats. Since then, I have found a few more species including the Lorquins Admiral butterfly (Limenitius lorquini) on cottonwood and the Anise Swallowtail (Papilio zelicaon) on fennel. Also, I was given some tiger moth caterpillars that others had found while on a collecting trip near Grass Valley, CA. Those were found on incense cedar (Calocedrus decurrens) and have yet to begin spinning their cocoons to prepare for pupation. All these species I am currently rearing and am hopeful to find more as the summer months begin to warm up.