Bug Spotlight!

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U.C. Riverside
Department of Entomology
Photo by: Photos by Marcella Waggoner 
The White-Lined Sphinx (Hyles lineata) Order Lepidoptera, Family Sphingidae 

Photos and text by Marcella Waggoner

Moths in this family are easily identified because they are large and have a characteristic triangular wing shape. Adults also have an unusually long proboscis that is used to suck nectar from long tube-shaped flowers. The larvae of many species have a spine or horn at the back end and are called hornworms. The White-lined Sphinx Moth (Hyles lineata), is the most common Sphingid in California. Adults have a whitish stripe running the length of the forewing. Larvae are brightly colored and conspicuous, varying in color from yellow to black and sporting yellow lines down the length of the body. The white-lined sphinx moth is especially common in desert areas. In years of low winter rainfall, the white lined sphinx moth may be completely absent. During years of heavy winter rains, when the desert supports a wide variety of annual plants that are food for the larvae, this sporadic species may be very common and can occasionally occur in tremendous numbers. From April to June the conspicuous and brightly colored caterpillars can be seen feeding on the low growing foliage of desert dandelion (Malacothrix), evening primrose (Oenothera sp.), buckwheat (Eriogonum), sand verbena (Abronia) and wishbone bush or wild four o'clock (Mirabilis bigelovii). Depending on the temperature, these active crawlers move from the food plants to the ground freely and are easily spotted. The larvae are evidently distasteful to some bird species that may spend up to fifteen minutes killing and removing the guts before eating a single larvae. Though the larvae generally stay at least partly shaded, they may drop off one plant to feed from the ground or move to another plant. When populations are especially large, the caterpillars can move in great hordes, devouring entire plants and piling up on roadways in slick masses. Adult white-lined sphinx moths feed on nectar while hovering around blossoms. Because of this behavior, they have often been mistaken for hummingbirds. Adults fly only in late spring and summer. White lined sphinx moths and other moths in this family are especially important pollinators of desert plants having large white, fragrant flowers. Two favorites are Jimson weed (Datura meteloides) and primrose (Oenothera sp.) which open their flowers at sunset. Sphinx moths can be found in dune areas, especially in the spring. You may also see them at night when they are drawn to lights. These moths often thump around clumsily before settling down near the light source.


2006  ERM-UC Riverside