10 Facts about Giant-Skippers
I’m often asked what is my favorite butterfly. As a professional Lepidopterist, and considering the incredible diversity of butterflies, this is almost impossible to answer, so I usually say “skippers!” But with over 4000 species of skippers (family Hesperiidae) worldwide, that doesn’t narrow it down much. Thus, when pressed to be more specific, I usually answer “Giant-Skippers!” Here are ten reasons why Giant-Skipper are simply astounding:
1. Giant-Skippers are members of the order Lepidoptera, and reside in the family Hesperiidae. Because of their unique morphology (see below), their classification has been unsettled until recently, and they have even been placed in their own family! Recent studies, considering DNA data, have confirmed that Giant-Skippers are indeed skippers, and have placed them, for now, in their own tribe, Megathymini (although more studies are needed to pinpoint their exact phylogenetic position in the skipper tree).
2. There are five genera of Giant-Skippers, Megathymus, Stallingsia, Aegiale, Turnerina, and Agathumus. Among these genera, there are 35 described species of Giant-Skippers, although various undescribed species remain to be formally named. In addition, of the many described subspecies, some might actually be species-level taxa.
3. As their name suggests, Giant-Skippers are among the largest of skippers, with the largest and bulkiest bodies of any skippers! The largest Giant-Skipper is Megathymus ursus (“The Bear”).
4. Giant-Skippers have their center of diversity in the desert SW of the USA, and adjacent arid parts of northern and central Mexico. They range as far south as Costa Rica (1 species, Agathymus indecisa), and as far north as North Dakota (1 species, Megathymus streckeri leussleri), although there are unverified reports of the latter from SE Saskatchewan as well.
5. The only larval foodplants for Giant-Skippers are Yuccas, Agaves, and Manfreda (Agavoideae). They are the only skippers able to feed on these tough plants. Most Giant-Skippers are highly specific as to which species of plant the larvae will accept for food, although a few (such as the Yucca Giant-Skipper) will feed on many species of Yucca. Here's a video about the Yucca Giant-Skipper (Megathymus yuccae).
6. Giant-Skippers have a totally unique life history, with larvae boring into the stalks, roots, and fleshy leaves of the foodplants (see above video). As a result of living in tunnels and cavities within root systems, the larvae have several unique morphological adaptations not found in other skippers.
7. Other than imbibing mineral-rich water (common in Agathymus males before mating), adults of Giant-Skippers don’t feed! All of their energy for flying, mating and laying eggs comes from resources stored up as larvae. Because of this, adults are short-lived.
8. Adults of most Giant-Skippers are rarely seen in nature. Because of their short time as an adult, and their very specific foodplant preferences, in addition to their characteristically very fast flight, any sighting of an adult Giant-Skipper is a noteworthy event! Some species, such as Megathymus cofaqui and Aegiale hesperiaris, are mostly crepuscular (active at dawn and perhaps dusk), another reason why they are rarely seen.
9. Larvae of Giant-Skippers are tasty! They are a favorite food of armadillos, and in Mexico, the larvae of Aegiale hesperiaris are a delicacy, frequently consumed by local human populations. In fact, in Mexico the highly priced larvae of A. hesperiaris are called “meocuilin” (or Maguey Worm)!
10. The larvae of one particular Giant-Skipper, Aegiale hesperiaris, are the original worms in tequila and mezcal bottles! As larvae were encountered in the fleshy Agave leaves during the processing of plants for fermentation, they were simply added to bottles of the finished product. However, these days, “worms” in tequila bottles are more often of Coleoptera, since Maguey Worms are so valuable.