Acadian Hairstreak

Endemic to the Northern United States and Southern Canada.

WSU Vancouver

June 10, 2022

Geography

Range Map

Acadian hairstreak (Satyrium acadia) is endemic to most of the Northern United States east of the Rocky Mountains.

It is also present in Southern Canada and Nova Scotia.

Recent Observations

Since 1990, observations of this butterfly are across a much smaller range in North America, with most of the contraction being in regions where land was heavily converted to agriculture.

The Rocky Mountains population may no longer be connected with the population surrounding the Great Lakes region.

Study Area

Populations in Cook County, Illinois were evaluated for this study from the Illinois Butterfly Monitoring Network which surveys butterfly communities at multiple sites each year.

Natural History

Species interactions

Host Plant

Various willow species (Salix spp.) host the hairstreak caterpillar. Black willow (Salix nigra) and silk willow (Salix sericea) are confirmed hosts in the southern and eastern portion of the range.

Nectar Plants

They are nectar generalists and have been observed feeding on milkweeds (Asclepias spp.), thistles (Cirsium spp.), meadowsweet (Filipendula ulmaria), and others.

Other species

Hairstreaks (like the one pictured) often have some beneficial association with ants when they are caterpillar. More research is needed for this species.

Habitat

Acadian hairstreaks can be found congregating at nectar sources, willow lined streams, marshes and moist woodlands.

Population Dynamics

Very little is known about the population structure of Acadian hairstreaks. More research is needed.
There is some evidence the species has northward range expansion, possibly tied to climate change.

Life Cycle

Adults

Butterflies fly in June through August in Illinois. They produce one brood a year (univoltine).

Eggs

Eggs are laid singly on willow twigs and do not hatch until spring. This hatched egg is from another hairstreak (Satyrium album).

Caterpillars

Caterpillars consume willow leaves in the spring. The caterpillars tend to be camouflaged like this banded hairstreak (Satyrium calanus).

Conservation

Listing Status

Despite the range contraction and loss of many populations in the Southern portion of the range, the Acadian hairstreak is globally secure . It is most secure in Montana, New York, Vermont, and Quebec, Canada. It is critically imperiled in Nova Scotia, Canada.

The species is not yet ranked for Illinois, but is nearly extirpated from the state and is now only seen in the Northeast corner of the state.

Recovery Efforts

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

Acadian hairstreak needs more research into the population trends, the natural history, and life history of this species. We had only two sites in our analysis, both appears to have declined throughout the observation period.