Northern Blue
Plebejus idas (Linnaeus, 1761)
Family: Lycaenidae
Subfamily: Polyommatinae
Identification: Geographically variable. Upperside of male iridescent blue, female brown with orange submarginal spots. Below, hindwing has a thin black line along outer margin which is broken into small dots at vein ends. Can be positively identified only by dissection of male genitalia and by locality.
Wing Span: 7/8 - 1 1/2 inches (2.2 - 3.8 cm).
Life History: Males patrol near host plants for females. Eggs are laid singly on stems of host plant or in debris beneath it. Second-stage caterpillars overwinter.
Flight: One brood from July-August.
Caterpillar Hosts: Plants of the heath family (Ericaceae) in the east; legumes of the pea family (Fabaceae) in the west.
Adult Food: Nectar from flowers including yarrow; dogbane; orange hawkweed; and white, alsike, and hop clover.
Habitat: Openings in mixed evergreen forests, bogs, wet meadows, seeps.
Range: Holarctic. Nova Scotia west through the Great Lakes area and southern Canada; north to Alaska; south to central California, southern Idaho, and southwest Colorado.
Conservation: Subspecies lotis is probably naturally rare with low population densities; it is found currently in only 1 out of 7 of its historic sites. Successional changes in vegetation due to human disturbance choked out the host plant Lotus formosissimus. Subspecies lotis has The Nature Conservancy rank of T1 - Critically imperiled because of extreme rarity (5 or fewer occurrences, or very few remaining individuals), or because of some factor of its biology making it especially vulnerable to extinction. (Critically endangered throughout its range). The species as a whole has The Nature Conservancy Global Rank of G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
NCGR:
Management Needs: The U. S. Fish and Wildlife Service recovery plan for the Lotis Blue cites the need for basic biological and ecological information about this butterfly. Three steps to recovery are listed: 1) protect remaining habitat and butterflies at the only known population site, 2) establish 3 new populations at different sites, and 3) determine the extent of the population and the size of secure habitats needed.
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Verified Sightings
Displaying 1 - 24 of 212 verified sightings
Observation date: Jul 30, 2022
Submitted by: scsmith1957
Region: Alberta, Canada
Verified by: Paul Prappas
Verified date: Feb 20, 2023
Observation date: Jul 19, 2020
Submitted by: jsaunders260
Region: Matanuska-Susitna, Alaska, United States
Verified by: Paul Prappas
Verified date: Feb 10, 2023
Observation date: Jul 19, 2020
Submitted by: jsaunders260
Region: Matanuska-Susitna, Alaska, United States
Verified by: Paul Prappas
Verified date: Feb 07, 2023
Observation date: Aug 09, 2019
Submitted by: Aat
Region: Alberta, Canada
Verified by: Paul Prappas
Verified date: Feb 07, 2023
Observation date: Aug 09, 2019
Submitted by: Aat
Region: Alberta, Canada
Verified by: Paul Prappas
Verified date: Feb 07, 2023
Observation date: Aug 06, 2022
Submitted by: Bob Patton
Region: Montana, United States
Verified by: stevekohler
Verified date: Jan 18, 2023
Observation date: Jun 22, 2022
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Nov 03, 2022
Observation date: Aug 01, 2021
Submitted by: NikkiM
Region: Park County, Wyoming, United States
Verified by: J_Martineau
Verified date: Oct 20, 2022
Observation date: Jun 14, 2019
Submitted by: Liz Osborn
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 16, 2022
Observation date: Jun 24, 2019
Submitted by: Liz Osborn
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 14, 2022
Observation date: Jul 28, 2019
Submitted by: Claire Christensen
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 14, 2022
Observation date: Jul 28, 2019
Submitted by: Liz Osborn
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 13, 2022
Observation date: Aug 12, 2022
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Aug 14, 2022
Observation date: Jul 14, 2022
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Jul 18, 2022
Observation date: Jul 16, 2020
Submitted by: jollygoodyellow
Region: Nova Scotia, Canada
Verified by: John Calhoun
Verified date: Feb 27, 2022
Observation date: Jul 15, 2020
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Sep 11, 2021
Observation date: Jul 15, 2020
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Sep 11, 2021
Observation date: Aug 09, 2021
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Aug 17, 2021
Observation date: Aug 09, 2021
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Aug 17, 2021
Observation date: Jul 28, 2021
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Aug 01, 2021
Observation date: Jul 28, 2021
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Aug 01, 2021
Observation date: Jul 03, 2012
Submitted by: bshettler
Region: Manitoba, Canada
Verified by: chalicerae
Verified date: Jul 26, 2021
Observation date: Jul 04, 2021
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: davidwdroppers
Verified date: Jul 21, 2021
Observation date: Jul 06, 2021
Submitted by: falco1
Region: Spokane County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 19, 2021
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