New England Bluet Jean Held

New England Bluet
Jean Held

Class
Insecta (Insects)
Family
Coenagrionidae (Pond Damsels)
State Protection
Not Listed
Not listed or protected by New York State.
Federal Protection
Not Listed
State Conservation Status Rank
S3
Vulnerable in New York - Vulnerable to disappearing from New York due to rarity or other factors (but not currently imperiled); typically 21 to 80 populations or locations in New York, few individuals, restricted range, few remaining acres (or miles of stream), and/or recent and widespread declines.
Global Conservation Status Rank
G3G4
Vulnerable globally, or Apparently Secure - At moderate risk of extinction, with relatively few populations or locations in the world, few individuals, and/or restricted range; or uncommon but not rare globally; may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors. More information is needed to assign either G3 or G4.

Summary

Did you know?

The New England bluet is one of 23 species of damselflies in the genus Enallagma found in New York State. This is the largest single dragonfly or damselfly genus in the state. The New England bluet has also been called the lateral bluet as its' specific name, laterale, refers to the black mark on the side of the 8th abdominal segment.

State Ranking Justification

In New York State, this species occurs within a fairly restricted range and is currently known from just 11 populations. Although it is likely that some additional sites will be found as a result of additional surveys, the number of new sites is not expected to be large. There are existing threats and a host of potential threats at known sites, and similar threats would be expected for any newly discovered sites as well.

Short-term Trends

There is no information on population trends for this species, although it seems likely that occupied sites have been lost or reduced in size due to changes in hydrology, water quality, groundwater withdrawal, off-road vehicle impacts, and other factors at some lakes and ponds in the Long Island portion of the species range.

Long-term Trends

There is no specific data, such as historically occupied sites that are no longer extant, to support the idea that this species has declined in New York over the long term. However, historical survey efforts were probably quite limited and the tremendous amount of development that has occurred on Long Island, particularly in Nassau County and western Suffolk County, undoubtedly eliminated at least some populations.

Conservation and Management

Threats

Any activities which degrade the sensitive hydrology or water quality of the ponds where it occurs could threaten populations of these damselflies. Examples include: ditching, filling, eutrophication and changes in dissolved oxygen content, direct effects of pesticides (e.g. for mosquito control or from agricultural runoff), and other chemical contamination from runoff or discharge of agricultural, industrial, or urban effluent. Introduction of fish may be a threat as a number of Enallagma species are thought to be restricted to, or reach their highest population levels in, fishless ponds. Historically, coastal plain ponds dried out completely during occasional severe droughts, which prevented fish from establishing themselves in these ponds. Today, many ponds in the Central Pine Barrens never go completely dry due to deep holes dug at the edge of nearly all coastal plain ponds, and several species of fish introduced by the public have become permanent pond residents. Off-road vehicle use along or near pond shores and groundwater withdrawal have been noted as specific problems in New England and New York (Carpenter 1990, Donnelly 1999). At the present time, only a few public water supply wells are currently located near existing coastal plain ponds on Long Island, so groundwater withdrawal may not be a major threat to known populations of this species (Central Pine Barrens Joint Planning and Policy Commission 2003). Future new supply water wells could pose a threat, if they are located near ponds occupied by this bluet. While groundwater sources are protected for the majority of ponds within the Central Pine Barrens Core Preserve, they are not protected for ponds in the Compatible Growth Area (Central Pine Barrens Joint Planning and Policy Commission 2003) or other areas of Long Island. The Westchester County populations could be threatened or negatively impacted by further lakeshore development. Fish stocking is a potential threat at one of the Orange County sites. Treatment of ponds for mosquito control relative to West Nile Virus may be a threat, particularly at sites on Long Island.

Conservation Strategies and Management Practices

The reduction or elimination of off-road vehicle use is needed at some coastal plain pond sites. Removal of introduced fish and non-native plants should be undertaken at sites where they are indicated as a potential problem and where it is practical to achieve positive results. Monitor damselfly populations in relation to water level fluctuation and other potential threats. Efforts to ensure that aerial pesticide spraying does not occur over, or in close proximity to coastal plain ponds and the adjacent uplands during the adult flight period would be desirable.

Research Needs

Research aimed at gaining a better understanding of the ecology of coastal plain pond damselfly species, including habitat preferences and threats to the species are needed.

Habitat

Habitat

The New England bluet inhabits ponds and small lakes with emergent vegetation or boggy edges. On Long Island, as in coastal states such as Massachusetts and Rhode Island, these ponds are typically sandy-bottomed coastal plain ponds (Carpenter 1991, Nikula et al. 2003, Lam 2004, New York Natural Heritage Program 2005). In Rhode Island, Carpenter (1991) has noted a particular association with emergent stands of rushes (Juncus) and pickerelweed. Although the majority of sites occupied by this bluet are in the coastal plain, it is also found at higher elevations away from the coastal plain in Pennsylvania and in the Hudson Highlands region of New York where it is found at ponds bordered by boggy vegetation (New York Natural Heritage Program 2005).

Associated Ecological Communities

  • Bog lake/pond (guide)
    the aquatic community of a dystrophic lake that typically occurs in a small, shallow basin (e.g., a kettehole) that is protected from wind and is poorly drained. These lakes occur in areas with non-calcareous bedrock or glacial till; many are fringed or surrounded by a floating mat of vegetation (in New York usually either bog or poor fen).
  • Coastal plain pond (guide)
    The aquatic community of the permanently flooded portion of a coastal plain pond with seasonally, and annually fluctuating water levels. These are shallow, groundwater-fed ponds that occur in kettle-holes or shallow depressions in the outwash plains south of the terminal moraines of Long Island, and New England. A series of coastal plain ponds are often hydrologically connected, either by groundwater, or sometimes by surface flow in a small coastal plain stream.
  • Coastal plain pond shore (guide)
    The gently sloping shore of a coastal plain pond with seasonally and annually fluctuating water levels. Plants growing on the pond shore vary with water levels. In dry years when water levels are low there is often a dense growth of annual sedges, grasses, and herbs. Submerged and floating-leaved aquatic plants, such as fragrant waterlily and pondweeds, may become "stranded" on the exposed shore. In wet years when the water level is high only a few emergents and floating-leaved aquatics may be noticeable. T
  • Coastal plain poor fen (guide)
    A wetland on the coastal plain fed by somewhat mineral-rich groundwater and slow decomposition rates of plant materials in the wetland (and thus develops peat). Plants are generally growing in peat composed primarily of Sphagnum mosses with some grass-like and woody components.
  • Dwarf shrub bog (guide)
    A wetland usually fed by rainwater or mineral-poor groundwater and dominated by short, evergreen shrubs and peat mosses. The surface of the peatland is usually hummocky, with shrubs more common on the hummocks and peat moss throughout. The water in the bog is usually nutrient-poor and acidic.
  • Eutrophic pond
    The aquatic community of a small, shallow, nutrient-rich pond. The water is usually green with algae, and the bottom is mucky. Eutrophic ponds are too shallow to remain stratified throughout the summer; they are winter-stratified, monomictic ponds.
  • Reservoir/artificial impoundment
    The aquatic community of an artificial lake created by the impoundment of a river with a dam. Reservoirs are constructed to collect water for municipal and/or agricultural water use, to provide hydroelectric power, and to improve opportunities for recreational activities (e.g., boating, swimming), and development.

Associated Species

  • Scarlet Bluet (Enallagma pictum) (guide)
  • Pine Barrens Bluet (Enallagma recurvatum) (guide)

Range

New York State Distribution

This species is uncommon in New York, with a fairly restricted range in the lower Hudson Valley, the Hudson Highlands, and Long Island. Within this range, it is currently known from just 11 ponds or small lakes. These locations include: five in Suffolk County, two in Westchester County, one in Rockland County, and three in Orange County. The recent date of discovery in Orange and Rockland counties, and the range of the species in Pennsylvania and New England, suggests that the range of this damselfly in New York may be somewhat broader in the Hudson Valley than the current records indicate. However, it is unlikely that the species will be found in other more distant regions of the state.

Global Distribution

The New England bluet is a northeastern species that is found from southern Maine south to New Jersey. Although its distribution is closely tied to the coastal plain, it is not restricted to this region as there are populations at higher elevations in the Poconos in Pennsylvania and in the Hudson Highlands in New York.

Best Places to See

  • Island Pond at Harriman State Park (Orange County)
  • Long Pond (Suffolk County)

Identification Comments

Identifying Characteristics

The New England bluet is one of a large number of species of small (typically 1-1.5 inches) damselflies in the genus Enallagma, collectively referred to as the bluets, and most of which are predominantly black and sky blue in coloration and quite similar to one another in overall appearance. Bluets have large, widely separated eyes with colored "eyespots" (or postocular spots) on the top of the head next to the eyes, black stripes on the thorax, and a pattern of black with blue (usually), red, orange, or yellow on the abdomen, and clear (untinted) wings. At 1-1.1 inches (25-28 mm) in length, the New England bluet is one of the smaller members of the genus (Lam 2004). In the New England bluet, the eyespots are small and tear shaped. The thorax is blue with black stripes on the shoulder and a broad, black stripe in the middle of the thorax. Like some other members of the genus, the abdomen has the overall appearance of having more blue than black. Abdominal segments 1 through 5 are predominantly blue with smaller black areas at the rear end of the segment. Segments 6 and 7 are mostly black, while segments 8 and 9 are again mostly blue. Segment 8 however, has a black mark on the side of the segment, hence the scientific name, laterale. The size of this lateral mark is variable. Segment 10 is black above and blue below. The thorax of the female is similar to the males, but the pale blue areas of the male are tan to blue-gray in females. The abdomen of the female lacks the alternating blue-black pattern of the male, as all segments are predominantly black above and pale, tan to blue-gray below. Bluet larvae are small, and fairly slim, with prominent eyes, short antennae, and three external gills attached to the rear of the abdomen. They climb among aquatic vegetation until they are ready to emerge as adults. (Nikula et al. 2003, Lam 2004, Carpenter 1991).

Characters Most Useful for Identification

The bluets are one of the most difficult odonate groups to identify. Examination of the terminal appendages at the end of the abdomen with a hand lens or microscope is often required to identify males to species while microscopic examination is required to distinguish most females.

Best Life Stage for Proper Identification

Mature adults are the best life stage for the identification of all damselflies. Larval identification requires the use of detailed taxonomic keys, can be very difficult, and can be very unreliable, especially in the case of larvae that are not yet mature. Larval identification is best done by people with a great deal of expertise in this area.

Behavior

As with most other damselflies, New England bluets are not strong fliers and spend most of their time flying through the emergent and shoreline vegetation at the ponds where they live. They also use forest roads or clearings close to the water, particularly after they have first emerged. The females lay their eggs in floating and emergent vegetation while flying in tandem with a male.

Best Time to See

This is an early-season species with a fairly brief flight period. Records for New York are from May 26 to June 23 (New York Natural Heritage Program 2005). Nikula et al. (2003) show a flight season for Massachusetts of mid-May to mid-July, while Westfall and May (1996) give an early date of May 6 for Massachusetts and a late date of July 19 for Maine.

  • Present
  • Reproducing

The time of year you would expect to find New England Bluet present and reproducing in New York.

Similar Species

  • Marsh Bluet (Enallagma ebrium)
    Female New England bluets are virtually indistinguishable from female Hagen's bluets without microsopic examination of certain features (the mesostigmal plates).
  • Hagen's Bluet (Enallagma hageni)
    Female New England bluets are virtually indistinguishable from female Hagen's bluets without microsopic examination of certain features (the mesostigmal plates).
  • Pine Barrens Bluet (Enallagma recurvatum) (guide)
    The New England bluet is most easily confused with the Pine Barrens bluet as it may also have a small black mark on the side of the 8th abdominal segment. The black lateral mark is smaller in the Pine Barrens bluet and is sometimes absent. The blue shoulder stripe of the Pine Barrens bluet is often pinched or sometimes broken (Lam 2004). The male abdominal appendages differ in the two species and should also be examined to confirm identification to species. The cerci is upturned in the Pine Barrens bluet and slightly bifid or, indented, in the New England bluet.

New England Bluet Images

Taxonomy

New England Bluet
Enallagma laterale Morse, 1895

  • Kingdom Animalia
    • Phylum Mandibulata (Mandibulates)
      • Class Insecta (Insects)
        • Order Odonata (Dragonflies and Damselflies)
          • Family Coenagrionidae (Pond Damsels)

Additional Common Names

  • Lateral bluet

Additional Resources

References

Carpenter, V. 1991. Dragonflies and damselflies of Cape Cod. Cape Cod Museum of Natural History. Brewster, MA. 79 pp.

Carpenter, V. A. 1990. An ecological and behavioral study of the barrens bluet damselfly (Enallagma recurvatum) including results of general odonate inventories, 1990. Unpublished report for the Massachusetts Natural Heritage Program. 43 pp.

Central Pine Barrens Joint Planning Commission, Protected Lands Council. 2003. Ecological principles for management and stewardship for the Long Island Central Pine Barrens. Pages 21-28 (Freshwater Wetlands Section).

Donnelly, T. W. 1992. The odonata of New York State. Bulletin of American Odonatology. 1(1):1-27.

Donnelly, T.W. 1999. The Dragonflies and Damselflies of New York. Prepared for the 1999 International Congress of Odonatology and 1st Symposium of the Worldwide Dragonfly Association. July 11-16, 1999. Colgate University, Hamilton, New York: 39 pp.

Gibbs, R.H. 1955. The females of ENALLAGMA LATERALE Morse and RECURVATUM Davis (Odonata:Coenagrionidae). Psyche 62(1). pp. 10-18.

Lam, E. 2004. Damselflies of the northeast: A guide to the species of eastern Canada and the northeastern United States. Biodiversity Books, Forest Hills, New York. 96 pp.

Needham, J.G., and H.B. Heywood. 1929. A handbook of the dragonflies of North America. Charles C. Thomas, Springfield, IL, 378 pp.

New York Natural Heritage Program. 2005. Biotics Database. Albany, NY.

New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.

Nikula, B., J.L. Loose, and M.R. Burne. 2003. A field guide to the dragonflies and damselflies of Massachusetts. Division of Fisheries and Wildlife, Natural Heritage and Endangered Species Program, Westborough, MA. 197 pp.

Westfall, M.J. Jr. and M.L. May. 1996. Damselflies of North America. Scientific Publishers. Gainesville, FL. 649 pp.

Links

About This Guide

Information for this guide was last updated on: April 19, 2005

Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Enallagma laterale. Available from: https://guides.nynhp.org/new-england-bluet/. Accessed May 25, 2019.

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