Blueberry Gray

Glena cognataria (Hübner, 1831)

Blueberry Gray
Canadian Biodiversity Research Facility (CBIF)

Insecta (Insects)
Geometridae (Loopers, Span Worms, Inch Worms, Geometer Moths)
State Protection
Not Listed
Not listed or protected by New York State.
Federal Protection
Not Listed
State Conservation Status Rank
Critically Imperiled, Imperiled, or Vulnerable in New York - Conservation status is uncertain; could be especially vulnerable, very vulnerable, or vulnerable to disappearing from New York, due to rarity or other factors. More information is needed to assign either S1, S2 or S3.
Global Conservation Status Rank
Apparently Secure globally - Uncommon in the world but not rare; usually widespread, but may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors.


Did you know?

The status of the blueberry gray is poorly known in New York. This species was historically widespread on Long Island and may still occur in unknown locations there.

State Ranking Justification

The current status is poorly known for New York. This species should turn up more widely than recent specimens known to the New York Natural Heritage Program indicate, both on ridges in the southeastern counties and on Long Island.

Short-term Trends

The short-term trends for this species are unknown.

Long-term Trends

The long-term trends indicate that the population has undergone a moderate to substantial decline (25% to 75% decline).

Conservation and Management


Loss of habitat to development or fire suppression is a threat. Potentially, wildfires or poorly planned prescribed burns could be a threat since it is unlikely that any life stage of this moth would survive in a fire. Spongy moth (Lymantria dispar) spraying should not impact this species if Bt (Bacillus thuringiensis - a bacterial biological control used on spongy moth caterpillars) is used, due to the phenology (timing of life cycles) of this species.



This is a species of heathlands, including bogs and pine barrens. A key habitat feature is extensive areas of Lowbush Blueberry (Vaccinium angustifolium and Vaccinium pallidum).

Associated Ecological Communities

  • Chestnut oak forest (guide)
    A hardwood forest that occurs on well-drained sites in glaciated portions of the Appalachians, and on the coastal plain. This forest is similar to the Allegheny oak forest; it is distinguished by fewer canopy dominants and a less diverse shrublayer and groundlayer flora. Dominant trees are typically chestnut oak and red oak.
  • Pitch pine-oak-heath rocky summit (guide)
    A community that occurs on warm, dry, rocky ridgetops and summits where the bedrock is non-calcareous (such as quartzite, sandstone, or schist), and the soils are more or less acidic. This community is broadly defined and includes examples that may lack pines and are dominated by scrub oak and/or heath shrubs apparently related to fire regime.


New York State Distribution

This species was collected in Ulster County in 1988, but historically it was widespread on Long Island (Rindge 1965) and there is no obvious reason why this species would not still occur there.

Global Distribution

This species occurs mainly along the coast, from Nova Scotia to Florida, but also inland in northeastern Pennsylvania, adjacent New York, and in the Virginia mountains (Rindge 1965). The range is not continuous.

Identification Comments

General Description

This is a fairly small, plain gray, Geometrid moth with feathered antennae in males.

Characters Most Useful for Identification

This is a fairly small, plain gray, Geometrid moth with feathered antennae in males. It is easily identified by anybody familiar with the group. There are no similar species in New York. Northern specimens tend to be smaller and with subdued markings, compared to the specimen illustrated by Covell (1984).

Best Life Stage for Proper Identification

Adult only.


The adults are nocturnal.


The foodplant has not been documented in New York, but lowbush blueberry (Vaccinium angustifolium and Vaccinium pallidum) are most often reported. Other heaths are probably used as well and Sand Cherry (Prunus pumila) and Pin Cherry (Prunus pensylvanica) are used in New England, which suggests the larvae may be somewhat polyphagous (feeding on many different kinds of food).

Best Time to See

The phenology is somewhat uncertain, but adults are likely to be present about late May to June and August with two broods. The pupae overwinter in the leaf litter or humus.

  • Reproducing
  • Larvae present and active
  • Pupae or prepupae present

The time of year you would expect to find Blueberry Gray reproducing, larvae present and active, and pupae or prepupae present in New York.

Blueberry Gray Images


Blueberry Gray
Glena cognataria (Hübner, 1831)

  • Kingdom Animalia
    • Phylum Arthropoda (Mandibulates)
      • Class Insecta (Insects)
        • Order Lepidoptera (Butterflies, Skippers, and Moths)
          • Family Geometridae (Loopers, Span Worms, Inch Worms, Geometer Moths)

Additional Resources


Allen, T.J., J.P. Brock, and J. Glassberg. 2005. Caterpillars in the field and garden. Oxford University Press, New York. 232 pp.

Brock, J. P., and K. Kaufman. 2003. Butterflies of North America. Kaufman Focus Field Guides, Houghton Mifflin Company, New York, NY 284 pp.

Covell, Charles V. 1984. A field guide to the moths of eastern North America. Houghton Mifflin Company, Boston.

Ferguson, Douglas C., 1955. The Lepidoptera of Nova Scotia Part 1 (Macrolepidoptera). Bulletin no. 2 of the Nova Scotia Museum of Science, Halifax, NS, Canada., 375 pp., black and white plates.

Forbes, William T. M. 1948. Lepidoptera of New York and neighboring states part II. Cornell University Agricultural Experiment Station Memoir 274.

Handfield, Louis, 1999. Le Guide des Papillons du Quebec, Scientific Version. Broquet Inc, Boucherville, Quebec, Canada, 155pp + plates.

McGuffin, W.C. 1977. Guide to the Geometridae of Canada. (Lepidoptera), II. Subfamily Ennominae. 2. Memoirs of the Entomological Soc. of Canada - No. 101. Ottawa.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Rindge, F. H. 1965. A revision of the Nearctic species of the genus Glena (Lepidoptera, Geometridae). Bulletin of the American Museum of Natural History vol. 129, article 3: 267-305.


About This Guide

Information for this guide was last updated on: December 20, 2007

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Glena cognataria. Available from: Accessed July 19, 2024.