Caterpillar Sleuthing

A few days ago I spied a group of caterpillars eating the leaves of a Loblolly Bay tree. What's so interesting about that? I find caterpillars eating leaves all of the time, right? Well, when I checked to see what these caterpillars might be I discovered that Loblolly Bay isn't listed as a larval host for any caterpillars in particular. Well, that could slow down the identification process. So let's start with the host, which we know, and then move on to the caterpillars to try and solve this mystery.

Loblolly Bay


Loblolly Bay (Gordonia lasianthus) is an evergreen shrubby tree that grows about 36 to 80 feet in height and is native to the Southeast of North America. Each summer it blooms with fragrant white blossoms that could give a magnolia a run for its money. However, Loblolly Bay is actually a member of the Tea (Thaecea) family and its bark was once used in the process of tanning leather.

What's in a name?

• Loblolly Bay (Gordonia lasianthus)
• Genus Gordonia: name honors British nursreyman James Gordon (1728-91) and includes about 30 species most of which are located in southeastern Asia and Indomalaysia.
• Species lasianthus: name derives for the Latin for "hairy flowered".

Unknown Caterpillars: What do we know so far and what does it tell us?

The larvae are eating Loblolly Bay which is not a listed host for any caterpillars: Since the caterpillars are eating from a host plant what is not regularly associated with any known caterpillars, I immediately considered moths as a suspect. Most butterfly host plants in Florida are well documented and butterflies tend to be specialists, limited to a very small group of closely related host plants for each species. Loblolly Bay isn't related to Red Bay (Persea borbonia) or Sweetbay Magnolia (Magnolia virginiana) so it likely wouldn't appeal to any of the butterflies that host on those trees. Moths tend to be much more generalist in their feeding habits, able to eat sometimes a very wide range of food plants. Some moths are known to host on more than 20 species of trees.

The larvae are feeding gregariously on their host plant: The caterpillars are feeding gregariously which may not point us in a direction to a particular species, but might help us to rule a species out later.

The caterpillars in question are yellow in color with black heads and spots and have long white lateral stripes the length of their bodies. There is a small but obvious hump on the backs of the caterpillars just below their heads: Looking at the physical characteristics of the caterpillar can be helpful next, but caterpillars can be incredibly variable in appearance. Caterpillars go through stages of development called instars which are marked by the shedding of their skin. From one instar to another caterpillars can change colors, lose or gain spots and tubercles, or even develop structures that look like antlers. The humped backs of this species is currently their most prominent feature and it reminded me of a few other caterpillars, namely Red Humped Caterpillars (Schizura concinna). Looking in to that species I found a group of moths called Prominents (Family Noctuoidea Subfamily Notodontida) many of which have a characteristic hump as a caterpillar in various stages.

And still, no answer:

Looking through every caterpillar guide I can find, I can't locate any photographs of species that look identical to our new friends. The only thing that is left to do is document the changes that happen as the caterpillars grow and progress through various instars to see if any of their new physical characteristics make for an easier identification. Stay tuned for new developments in this story of Caterpillar Detective.