Skippers: Mary’s giant-skipper (Agathymus mariae)
(Lepidoptera: Hesperiidae: Megathyminae: Aegialini)
Profile prepared by Mace Vaughan and Matthew Shepherd, The Xerces Society for Invertebrate Conservation
Mary’s giant-skipper is found in desert scrub in Chihuahua and Coachila and just north of the border in southern Texas and New Mexico. Its larval hostplant is lechuguilla agave, a plant that is threatened by grazing, fire, and plant collectors. The lack of information on this species, particularly on its populations in Mexico, means that it cannot be shown to be secure. More research is required to establish its status.
Xerces Red List Status: Data Deficient
Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
USA – Endangered Species Act: None
USA – state status: None
IUCN Red List: N/A
This species is designated Data Deficient because of the lack of information about its abundance and distribution in the Mexican part of its range. There are a number of threats to its habitat and it has a restricted distribution.
Mary’s giant-skipper is a medium sized butterfly in the family Hesperiidae. Its wingspan is 42 to 48 mm.
The upperside is black-brown with olive scales at the wing bases and a pale border. Both wings have postmarginal bands of yellow spots. These bands are wider on females. Underside of the wings are gray with faint dark markings. The forewings have a darker brown patch and the hindwings sometimes have a vague, light-colored, postmedian band.
Agathymus mariae (complex including gilberti) (Barnes & Benjamin), 1924.
Habitat is desert hills and thorn scrub. The larval hostplant is lechuguilla agave (Agave lechuguilla).
There is one flight from September to November. During this time adults do not feed, although males sip moisture from mud. Males perch near the hostplant during the morning. Females will lay eggs singly on the host. These fall to the base of the plant from where the young caterpillar hatches and crawls to a leaf tip where it burrows inside to eat the pulp and then hibernate. In the spring the caterpillar makes a new burrow in a leaf base where it feeds on sap until ceasing activity for the summer. Before pupating, the caterpillar enlarges the opening of its burrow and makes a silk trap door from which the adult can emerge.
Southern New Mexico, southwestern Texas, and northern Mexico (Chihuahua and Coachila).
Courtesy of Butterflies and Moths of North America, Big Sky Institute.
The principal threats are from grazing, wildfire, and plant collectors. All of these reduce the availability of the agave larval hostplant.
Protection of its habitat and ensuring adequate abundance of larval hostplants.
Additional research into appropriate habitat management and surveys to establish current population sizes and locations, especially in Mexico.
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Big Sky Institute, Butterflies and Moths of North America: Mary’s giant-skipper (Accessed 1/21/09)
Nearctica; The Butterflies and Skippers of North America: Mary’s giant-skipper (Accessed 5/4/05)
NatureServe Explorer (Accessed 9/23/08)
Vaughan, D. M., and M. D. Shepherd. 2005. Species Profile: Agathymus mariae. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation.