Dusky dune moth (Copablepharon longipenne) COSEWIC assessment and status report: chapter 2

Species Information

The Dusky Dune Moth (Copablepharon longipenne Grote 1882) is a medium-sized, light brown moth that has a line of black dots on the forewing. It occurs as two subspecies, of which only the nominate form occurs in Canada.

 

Distribution

Copablepharon longipenne is found from southern Manitoba, Saskatchewan, and Alberta to western Texas and southern New Mexico. It is associated with the Great Plains. Its range is 1 258 285 km² globally and 164 480 km² in Canada. Since 1922, C. longipenne has been recorded at 12 localities in Canada: four in Alberta, seven in Saskatchewan, and one in Manitoba.

 

Habitat

Copablepharon longipenne is associated with sparsely vegetated active sand dunes. It is considered a habitat specialist. Field observations suggest that the presence of open sand is important for reproduction; C. longipenne was observed laying eggs on the edge of active dunes. Active dunes in the Canadian prairies have declined in the past 100 years as increased precipitation has led to vegetation development.

Most Canadian sites with known or suspected C. longipenne populations occur in publicly owned lands, primarily provincial lands that are leased for cattle grazing. Three populations or suspected populations occur in protected areas.

 

Biology

Little is known about the biology of C. longipenne. Reproduction occurs once per year during a single flight season. In Canada, the flight season is approximately ten weeks long and extends from the middle of June to the middle of August. Adults have been observed nectaring on the flowers of dune plants during the evening. Mating has been observed to occur on plants or on the sand surface near vegetation. Eggs are deposited in a group approximately 1 cm below the sand surface.

Larval feeding has not been observed except for one case where larvae were feeding on the below-ground parts of roses. Based on the variability of plant species recorded within the immediate vicinity of sampling sites, C. longipenne is not likely to be restricted to a single host-plant for adult nectaring, reproduction, or larval feeding.

The dispersal abilities of C. longipenne have not been measured. There is no information that indicates it migrates.

 

Population Sizes and Trends

There is no quantitative information on population sizes and trends for C. longipenne. Based on the stabilization trends of sand dunes in the Canadian prairies, it is inferred thatC. longipenne populations are declining at a rate of 10–20% per decade.

The US population near Fort Peck, Montana, is approximately 270 km south of the closest Canadian population. The possibility of rescue over this distance is unlikely.

 

Limiting Factors and Threats

The progressive stabilization of sand dunes caused by vegetation colonization is considered a threat to C. longipenne. This threat affects all populations in Canada.

Development activities that result in destruction of sand dunes are considered a possible threat to C. longipenne. However, some disturbance associated with development may create habitat for C. longipenne by increasing open sand.

Populations of C. longipenne in Canada may be at risk from demographic collapse. Populations of C. longipenne are spatially isolated and may have increased risk of extinction. Demographic collapse is considered a possible threat.

Grazing is a possible threat to C. longipenne. It may initiate active sand movement in dunes and limit colonizing vegetation. However, it may cause soil compaction and browsing of vegetation that is used for larval feeding, and may also destroy eggs, larvae, or pupae.

Recreation may be intensive in some sand dunes and result in loss of vegetation, disturbance to sand substrates, and destruction of eggs, larvae, and pupae. Recreation may also maintain or create open sand habitats. Recreational activities are considered a possible threat.

 

Special Significance of the Species

Copablepharon longipenne is closely associated with active sand dunes, a regionally rare habitat in the southern Canadian prairies. It can be considered one of several focal species representing the sensitivity and uniqueness of this habitat type in Canada.

There is no information to suggest that C. longipennehas, or had, an important cultural or economic role for First Nations.

 

Existing Protection or Other Status Designations

Copablepharonlongipenneis not protected in any jurisdiction in Canada or the United States and its conservation status has not been ranked by any provincial or federal organizations.