Listing
Jan 20, 1984
Jan 20, 1984 Listing (Warranted But Precluded)
Findings on Pending Petitions & Description of Progress on Listing Actions; 49 FR 2485-2488
- Publication type: 12m petition finding
Item 1
FWS Focus
Overview
Characteristics
Overview
The Uncompahgre fritillary butterfly was discovered on Uncompahgre Peak, Hinsdale County, Colorado on July 30, 1978. It was subsequently described as a new species. Since listing and the completion of the recovery plan, the number of confirmed colonies has increased from two to 11. Population estimates have increased from about 1,000 to somewhere between 3,400 and 23,000 at the three currently monitored colonies. Similarly, the other eight qualitatively-monitored populations have persisted despite four of the colonies apparently having no individuals during one or two surveys in different years since 2001.
The only observable current impacts to the butterfly are caused by relatively minor habitat degradation from hiking trail erosion, widening and braiding on the edge of colonies at Mt. Uncompahgre and Redcloud Peak, as well as short-term impacts from rapid sheep trailing and grazing through Mt. Uncompahgre. Neither of these actions occur at a level to be considered a threat to the species. Climate change has not been an observable threat to either the Uncompahgre fritillary butterfly or its habitat to date, but is a potential future threat that should be monitored, because it may pose the largest threat.
Scientific Name
Boloria acrocnema
Common Name
Uncompahgre fritillary Butterfly
FWS Category
Insects
Identification Numbers
Characteristics
Characteristic category
Habitat
Characteristics
Habitat
All known populations are associated with large patches of snow willow above 3,780 meters (12,400 feet) which provide food and cover. The species has been found only on northeast-facing slopes, which are the coolest and wettest microhabitat available.
Characteristic category
Food
Characteristics
Food
Snow willow is the larval food plant, while adults take nectar from a wide range of flowering alpine plants.
Characteristic category
Life Cycle
Characteristics
Life Cycle
Females lay eggs on snow willow (Salix reticulata spp. nivalis), which is the larval food plant. The species is believed to primarily have a biennial life history, which means that it requires two years to complete its life cycle. Eggs laid in 2008, would be caterpillars in 2009 and mature into adults the following even-numbered year 2010. The odd-and even-year broods may function as essentially separate populations but recent evidence suggests more mixing that initially thought. Some caterpillars may take two summers to mature rather than three, and slowly developing caterpillars may take up to four years to mature. For example, if an egg is laid in 2009, the individual would normally spend all of 2010 as a caterpillar, metamorphose into a butterfly and reproduce to complete the normal biennial lifecycle in 2011. Quickly developing caterpillars could hatch from an egg in 2009, and then metamorphose into an adult and reproduce in 2010. However, this pattern may be extended through 2011, and metamorphosing into an adult and reproducing in 2012. Very dry or very wet weather is suspected to be a factor in population changes, and may influence length of time to maturity, but no correlation to weather or other potential influences has been determined. The butterflies live as adults for only one to two weeks.
Life Span
The butterflies live as adults for only one to two weeks.
Characteristic category
Behavior
Characteristics
Behavior
Uncompahgre fritillary butterfly movement is limited to their habitat patches. Genetic analyses currently underway may help determine if there is connectivity between colonies.
Characteristic category
Physical Characteristics
Characteristics
Color & Pattern
Males have rusty brown wings criss-crossed with black bars, with the wings of the female somewhat lighter. Underneath, the forewing is light ocher and the hindwing has a bold, white jagged bar dividing the crimson brown inner half from the purple-grey scaling on the outer wing surface. The body has a rusty brown thorax and a brownish black abdomen.
Size & Shape
The Uncompahgre fritillary is a small butterfly with a 2 to 3 cm (1 inch) wingspan.
Timeline
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