Black Dash

This skipper is endemic to the Northeastern United States.

WSU Vancouver

June 10, 2022

Geography

Range Map

Black Dash (Euphyes conspicua) is a butterfly endemic to the . Rare historical occurrences have been as far south as Oklahoma and South Carolina ( BAMONA ).

More recent observations put the and .

Study Area

We examined black dash populations in Illinois in parts of Cook, DuPage, Kane, and McHenry Counties.

The data comes from the Illinois Butterfly Monitoring Network which surveys butterfly communities at multiple sites each year.

Natural History

Host Plant

Narrow leaved sedges (Carex spp.) growing in open wetlands. Upright sedge (Carex stricta) is the only species that has been confirmed as a hostplant, but the sedge is not present across the range.

Nectar Plants

Black dashes have been known to nectar regularly. Some preferred species include wild bergamot (Monarda fistulosa), swamp milkweed (Asclepias incarnata) and pickerelweed (Pontederia cordata).

Habitat

Black dashes are associated with open wetlands in previously glaciated areas. Wetlands dominated by upright sedge and water sedge (Carex aquatilis) is one type of wetland the butterfly can be found in. Black dash look similar to their closer relative, the Dion skipper which is present throughout the range of the dash. The black dash may only use hosts that are wetland species, while the Dion skipper is flexible in its diet and present in drier habitats.

The Illinois DNR has found that the species is absent from wetlands invaded by Phalaris spp. and Polygonum spp.

Wetlands with host plants of the black dash.

Population Dynamics

Butterflies are generally found in low numbers across most wetlands with thin leaved sedges (Carex spp.).
Many skippers are highly mobile. Nectar sources are often distributed in separate areas from the host plants for the black dash, but there are no studies on the dispersal of the butterflies.
There are many natural and life history details unknown about this skipper.

Life Cycle

The life cycle of the black dash is largely unknown. Overwintering stage, additional host plants, and duration of each life stage is uncertain.

Adults

The butterfly is typically flying in July and August in Illinois, with some areas throughout its range beginning their flight in June. All populations have one brood each year (univoltine).

Other skippers

Other skippers in the Euphyes genus, such as this dun skipper (Euphyes vestris), overwinter as caterpillars and pupate in a nest of leaves and silk.

Egg

Eggs are laid singly on blades of host plants, like this dion skipper egg (Euphyes dion)

Conservation

Listing Status

In Illinois, the black dash is listed as vulnerable by NatureServe . They are the most secure in Wisconsin and the least secure in Delaware, Vermont, and West Virginia. They may have been extirpated from Virginia.

Recovery Efforts

Abundance Surveys and Habitat Maintenance

The Forest Preserve District of DuPage County in Illinois (FPDDC) conducts regular Pollard-walk relative abundance surveys for this species. Conservation efforts for black dash habitat include prescribed fire, removing and burning brush, and manual removal of invasive species.

To further inhibit the growth of invasive species, land managers apply herbicide to stumps after removal. Problematic invasives in DuPage County, IL are reed canary grass (Phalaris arundinacea), autumn olive (Elaeagnus umbellata), and glossy buckthorn (Rhamnus frangula).

Illinois Wildlife Action Plan

Illinois Wildlife Action Plan has two campaigns to preserve and improve wildlife habitats that include black dash habitat: Wetland Campaign , and Farmland and Prairie Campaign . However, these programs currently only target vertebrate species for conservation, like this blue-spotted salamander from Cook County, IL.

Population Trends

We found no association between the change in abundance and phenology. Most sites had data into the mid-2010s.

Below we show an example of a black dash site with advancing phenology.