Common and Not-So-Common Lepidoptera at the Park

Red Admiral Butterly (Vanessa atalanta)

While on a morning hike yesterday, I was staring through a Honey Mesquite tree (Prosopis glandulosa) to observe a Red Admiral (Vanessa atalanta) as it fluttered past.  Red Admirals are in abundance here.  Their larval food sources (host plants), members of the nettle family (Urticaceae), are ubiquitous throughout the hill country.  I've never seen so many admirals lapping up sap from tree wounds or puddling around scat on trails as I have since moving here.  It was in the midst of watching this very common species that I caught a glimpse of something on a limb of the mesquite tree that really intrigued me.  It wasn't a butterfly, but instead the larva of a moth, that would hold my attention from this point on.

Making its way along a small branch was an odd looking caterpillar, bright orange head and black body.  The first thing I saw were a few pairs of tentacles on and behind the head of the caterpillar, (later I would note the tentacles at the back of the larva).  While most people think these long, thin parts of caterpillar anatomy are antennae, they are actually sensory tentacles.  Antennae on most caterpillars are rather short and are found very near the mouth.  I approached the larva and noticed very pronounced spiracles along the length of the body, holes which the caterpillar uses for respiration.

Wilson's Wood-nymph Caterpillar (Xerociris wilsonii) - note the spiracles (holes) along the length of the body used for respiration.

Upon examination of the caterpillar, I realized I was looking at a Wilson's Wood-nymph Moth (Xerociris wilsonii) caterpillar.  Between the two of us, I was rather excited!  It was my first look at this species and I intended to take my time observing this one.  After spending quite a long time admiring and studying the larva, I snapped a few photos to share with you.

Wilson's Wood Nymph (Xerociris wilsonii) caterpillar on Honey Mesquite tree (Prosopis glandulosa) limb.

Wilson's Wood-nymph caterpillars feed on members of the Vitaceae plant family.  The members of this plant family are most often woody vines sporting tendrils used for climbing and attaching to structure.  The most famous members of the Vitaceae family are grapes and Virginia Creeper.  I found Sorrelvine (Cissus trifoliata) growing not twenty feet away from the Honey Mesquite tree where the caterpillar was.  Sorrel vine is also a member of the Vitaceae family of woody vines which sport tendrils for climbing and attaching and a frequent larval food source for this species of moth.

Now, I can't wait to return to the same park to observe the adult!  The Moth that this caterpillar becomes is elegant and striking in its beauty.  Even if the caterpillar has a face only a mother could love...

Wilson's Wood-nymph Caterpillar, with head-on view of tentacles.