White Lined Sphinx Moth Caterpillar (larva)

(Fig. 01)

(Fig. 02) (Fig. 03) Picture Notes: I have observed these caterpillar on various hikes over the past several years. Most recently we spotted some of them on a hike to the Ireteba Mountains on 04/16/2019. During a hike on 09/27/2012 hiking across Cottonwood Valley near the Wilson Cliffs and the Late Night Trail, we encountered literally dozens of caterpillars (Figs. 01 and 04 & 05). These critters, with orange and black markings and a horn on its tail. I have also spotted them in large numbers in places south along Lake Mead and into the Eldorado Valley. Some of these specimen's were as long as 3 inches. Their colors were quite impressive. Over the next couple of weeks these caterpillars will bury themselves in the ground to begin their transformation into white-lined sphinx moths. A couple of the members in our group actually saw one of these digging his way into the ground.

Description: White-lined Sphinx Moths are among the largest flying insects of the deserts, with adult wingspans sometimes exceeding 5 inches. Larvae can be just as long, with most having a prominent horn at the rear of their fleshy body. When alarmed, these larvae rear up their heads in a threatening sphinx-like posture and may emit a thick, green substance from their mouths. Once these caterpillar's complete their transformation, the moths emerge at dusk from their hiding places and begin feeding on the nectar of flowers. They are throughout all the North American desert regions. They can be seen in most habitats and on many desert plants, especially after rains. Most people only see the larvae, commonly know as the white sphinx caterpillar or the hornworm. The caterpillars feed on desert wildflowers in the spring. They are eating machines and can wipe out whole fields of wildflowers. The body of the white-lined sphinx moth ranges in length from 2 1/2 to 3 1/2 inches. It has a prominent brown head, a brown thorax with 6 white stripes and a brown abdomen with paired dark spots on each segment. The forewings are brown with a buff-colored band from base to tip and veins outlined in white. The hind wings are pink, turning to dark brown near the margins. Sphinx moths emerge at dusk from their hiding places and begin feeding on the nectar of flowers. Their size, combined with their rapid wing beats, allows them to hover and feed in the manner of hummingbirds, for which they are sometimes mistaken.This manner of flight requires a great deal of energy and creates a good deal of heat in the moth's body. For these reasons, moths feed exclusively on nectar and seek flowers which produce large amounts of this water source, and also contain high amounts of sugar. Such is the case with the evening primrose (Onagraceae) family, and particularly the dune evening primrose, which the white-lined sphinx moth is responsible for pollinating.

(Fig. 04)

(Fig. 05)