Alabama Butterfly Atlas

Adult Yucca Giant-Skippers appear in early spring. With their stout bodies, stubby wings, and small heads, they resemble large moths. Their flight has been described as "hurtling," "barging," and "erratic," and an encounter with them can be somewhat startling. Males whizz through the air with whistling wings, often returning to the same perch that they left--typically within sight of the nearest yucca. Neither sex is known to take nectar from flowers, although males may sip from moist earth. Because they do not feed, females are often immobile when not involved in mating or ovipositing behaviors.  These large skippers live in isolated colonies and are rarely encountered in large numbers or far from yucca plants. There is only one generation each year.  

Yucca Giant-Skippers belong to the genus Megathymus (Giant-Skippers) and exhibit many of the life history elements that are unique to the group. While first and second instar caterpillars construct shelters by eating into the thick leaves and then silking the opening, third instar caterpillars bore into the crown of the yucca plant and tunnel downward to feed on the roots. As the caterpillars eat, frass collects at the point of entry in the crown.  Eventually they construct a structure that looks somewhat like a cigar. Formed with silk and dung, it projects above the original point of entry. These shelters are typically referred to as "tents" or "chimneys." The caterpillar remains in its tunnel throughout the winter, at times crawling to the top to deposit more frass. It pupates within the tunnel in late winter or early spring.  The chrysalis eventually uses its large, bristly cremaster to move itself to the top of the larval chimney. The emergent butterfly crawls out and perches on the chimney while its wings dry and harden. The only other skipper in our area that utilizes this method of caterpillar development is the Cofaqui Giant-Skipper, a member of the same genus. 

Yuccas grows in a variety of open habitats--at least four species occur in Alabama. Yucca Giant-Skippers should be looked for wherever the plants are found. However, stands of yucca are much more common than colonies of Yucca Giant-Skipper. The exact requirements for colonization are not known, and the skippers are absent from many sites that appear to be suitable. Yucca Giant-Skippers do not normally live near human habitations.

These large skippers are resident along much of the southern third of the United States.  In Alabama, they have been documented sporadically in the upper two-thirds of the state but are probably more widespread.