Skippers: arogos skipper (Atrytone arogos)
(Lepidoptera: Hesperiidae: Hesperiinae)
Profile prepapred by Matthew Shepherd, The Xerces Society for Invertebrate Conservation
The arogos skipper is scattered in isolated populations across much of the United States west of the Rockies, but in no location can it be considered secure. Estimates put its population decline at 99-100 percent in most of its range. East of the Mississippi it is extirpated from much of its range: its stronghold is New Jersey, where it is state-listed as Endangered. It is reliant on relatively undisturbed prairies and grasslands, a habitat that has suffered badly from development and agricultural conversion. Surviving populations of the skipper are susceptible to frequent fires and pesticide use.
Xerces Red List Status: Vulnerable
Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
USA – Endangered Species Act: None
USA – state status: IL, NJ, NY: Endangered
IA: Species of Concern
IUCN Red List: N/A
The arogos skipper is scattered in isolated populations across much of the United States east of the Rockies, however it is in severe decline in almost its entire range. The eastern subspecies, A. a. arogos, has disappeared from most of its recorded locations east of the Mississippi and is barely surviving at the remaining locations. The current stronghold for this subspecies is New Jersey, where it is state-listed as Endangered. The western subspecies, A. a. iowa, is faring better, especially in the southern parts of its range, but cannot be considered secure. Overall, the population decline has been estimated as “99- 100% in most parts of the range” (NatureServe).
This butterfly receives no protection federally but is listed by a number of states. In Illinois (Endangered), Minnesota (Threatened), and Iowa (Species of Concern) it is listed as Atrytone arogos. New Jersey and New York both list the subspecies Atrytone arogos arogos as Endangered.
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The arogos skipper is a small butterfly in the family Hesperiidae (skippers). Its wingspan is between 1 1/8 and 1 7/16 inches (29 to 37 mm). The upperside of the wings is yellow-orange with black borders which are wider in females. Underside of hindwing is yellow with paler veins.
Atrytone arogos (Boisduval & LeConte), 1834. There are two subspecies, A. a. arogos and A. a. iowa.
The arogos skipper is reliant on relatively undisturbed prairie and grassland habitats through most of its range. The exception appears to be in New Jersey, where it is found on highly disturbed fields and rights-of-way, although these are mostly remnants of sand prairies.
There are two broods between April and September in the south and one in June and July in the north. In prairie regions, the hostplant is usually big bluestem (Andropogon gerardii) and sometimes little bluestem (Schizachyrium scoparium). Hostplants vary elsewhere, including pine barren sandreed (Calamovilfa brevipilis) in Carolina pine barrens and lopsided Indiangrass (Sorghastrum secundum) in Florida.
Males perch on low vegetation near to larval hostplants to wait for females. Females lay eggs singly under hostplant leaves. Caterpillars feed on leaves and live in tent s of two leaves silked together. Fourth-stage caterpillars hibernate, complete their feeding the next spring, and pupate in a leaf cocoon in vegetation about three feet above the ground.
The historic distribution included most of the states west of the Rockies (it was not recorded in a cluster of states below the Great Lakes, in the Appalachians, nor in New England), although occurrences were widely scattered and isolated colonies were recorded in only around two hundred counties. Subspecies iowa occupies the western part of the range and subspecies arogos is found in the east.
Current distribution is more limited and it is probably extirpated from most of its locations east of the Mississippi and many of those to the west.
Courtesy of Butterflies and Moths of North America, Big Sky Institute.
Prair