Little Bluet Ellen Pehek

Little Bluet
Ellen Pehek

Class
Insecta (Insects)
Family
Coenagrionidae (Pond Damsels)
State Protection
Threatened
Listed as Threatened by New York State: likely to become Endangered in the foreseeable future. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
S1
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
G4
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.

Summary

Did you know?

Female Little Bluets oviposit in floating or emergent vegetation on ponds while "in tandem" or coupled with males after mating (Nikula et al. 2003). This behavior is not unique to this species, but not all damselflies do this. This strategy reduces competition from other males: A male ensures that other males cannot mate with a female before she lays her eggs.

State Ranking Justification

In New York, Little Bluets have been documented in three locations in Suffolk and Queens counties (New York Natural Heritage Program 2011). A number of sites with suitable habitat were searched during the New York Dragonfly and Damselfly Survey (2005-2009), but even with increased effort looking for the species in recent years, only three locations are known in the state (White et al. 2010). There are a number of threats to these locations (see Conservation and Management section).

Short-term Trends

The population at one Suffolk county location was estimated to have excellent viability in 2009, with an estimated 868 individuals observed (New York Natural Heritage Program 2011, White et al. 2010). Population estimates have not been made for other sites (another Suffolk county location and one Queens county location). Information on the species prior to the late 1990s is very limited, with documented observations at just one of these sites prior to 1995 (New York Natural Heritage Program 2011).

Long-term Trends

Recent observations since 1995 have been noted in Suffolk and Queens county sites and the species had been observed at one of three extant sites prior to 1926 (New York Natural Heritage Program 2011). Little Bluets were documented historically at two additional sites on Long Island, but have not been seen there in recent years and long-term information regarding population size is not available prior to the late 1990s (Donnelly 1999, New York Natural Heritage Program 2011). Observations are fairly recent and long-term trends are unclear, but the species may be in decline in New York.

Conservation and Management

Threats

The largest New York population's habitat has residential development surrounding it and is used for recreation where trampling of pond vegetation has been observed (New York Natural Heritage Program 2011). In 2009, invasive Asiatic clams (Corbicula corbicula) were found at this location and monitoring the site every two years with a threat assessment is suggested (White et al. 2010). Any activity which might lead to water contamination or the alteration of natural hydrology could impact Little Bluet populations (NYS DEC 2005). Such threats might include roadway and agricultural run-off, ditching and filling, eutrophication and nutrient loading from fertilizers and septic systems, changes in dissolved oxygen content, and development near their habitats (NYS DEC 2005). Groundwater withdrawal is a potential threat in lentic habitats on Long Island, as are invasive plant species replacing native plants required for oviposition (New York Natural Heritage Program 2011). Both emergence rates and/or species ranges may shift for odonate species as a result of climate change (Kalkman et al. 2008).

Conservation Strategies and Management Practices

Any efforts to reduce roadway and agricultural run-off, eutrophication, development of upland borders to ponds and resulting increased groundwater withdrawal, invasive plant and animal species, trampling of vegetation from recreation, and ditching and filling activities should be considered when managing for this species (NYS DEC 2005, White et al. 2010). Maintenance or restoration of native shoreline vegetation and surrounding upland habitat will benefit this species, as females require native emergent vegetation for successful reproduction and spend much of their time in upland habitats away from the breeding pond (Gibbons et al. 2002, White et al. 2010).

Research Needs

Further inventory is needed to define the extent of populations of Little Bluets in New York. In addition, research is required to understand the habitat requirements and threats to this species. In particular, the impact of the newly arrived invasive Asiatic clam (Corbicula corbicula) at a Suffolk county site should be evaluated through monitoring and a threat assessment (White et al. 2010). A recovery plan for the species should be developed and appropriate management guidelines should be adopted for its persistence in known locations (NYS DEC 2005).

Habitat

Habitat

Little Bluets are known to inhabit ponds and lakes with sandy substrate, mainly in coastal plain ponds with emergent vegetation along the shoreline (Carpenter 1991, Lam 2004). The largest Long Island population is known from a coastal plain pond which contains the following emergent plants: three-square bulrush (Schoenoplectus pungens), jointed rush (Juncus articulatus), many-flowered pennywort (Hydrocotyle umbellata), seven-angle pipewort (Eriocaulon aquaticum), and golden hedge-hyssop (Gratiola aurea). The pond is surrounded by a wooded upland as well as residences (New York Natural Heritage Program 2011). Other studies in New England indicate a strong association with between little bluets and E. aquaticum (Brown 2005).

Associated Ecological Communities

  • 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

Associated Species

  • Familiar Bluet (Enallagma civile)
  • Skimming Bluet (Enallagma geminatum)
  • Orange Bluet (Enallagma signatum)
  • Slender Bluet (Enallagma traviatum)
  • Swamp Spreadwing (Lestes vigilax)

Range

New York State Distribution

In New York, Enallagma minusculum is known to occur at three locations, two in Suffolk county and one in Queens county (New York Natural Heritage Program 2011). Two of the locations were investigated as part of a special NYDDS effort; the third site in Queens County was documented by NYC Parks staff in 2008.

Global Distribution

The distribution for Little Bluet is North Carolina, the northeastern United States, and southeastern Canada (Nikula et al. 2003). More specifically, they are known from North Carolina, New York, Connecticut, Rhode Island, Massachusetts, New Hampshire, Maine, New Brunswick, Nova Scotia, and Prince Edward Island (NatureServe 2010, Abbott 2007).

Best Places to See

  • As this species is considered sensitive by the NYS DEC, site specific locations are not made available.

Identification Comments

Identifying Characteristics

Little Bluets are some of the smallest in the genus Enallagma, known to be 24-28 mm in total length. Male abdomens have an equal amount of blue and black (Nikula et al. 2003). Males have a purple thorax and head upon maturity (Lam 2004). Males also have a broad, black mid-dorsal stripe and shoulder stripes with abdominal segments 8-9 entirely blue (Nikula et al. 2003). Females have a thorax similar to males, with blue, green, or buffy areas and a black abdomen dorsally (Nikula et al. 2003, Lam 2004). A blue ring is usually present at the base of abdominal segment 8 on females (Lam 2004). Males are distinctive and females are best separated from other species through examination of their mesostigmal plates under a microscope (Lam 2004).

Best Time to See

In Maine, E. minusculum's flight season is from mid-June through late August (Brunelle & deMaynadier 2005). Connecticut reports adults from early June through mid-August (Lam 2004) and New York dates for confirmed observations span from June 4 to July 14 (New York Natural Heritage Program 2011).

  • Present
  • Reproducing

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

Similar Species

  • Variable Dancer (Argia fumipennis violacea)
    Male Variable Dancer's are larger than Little Bluets, and have more extensive purple coloration and forked shoulder stripes (Lam 2004).
  • Marsh Bluet (Enallagma ebrium)
    Female Marsh Bluets are similar to Little Bluets, but usually lack a partial pale ring on the base of abdominal segment 8 and differ in mesostigmal plates (Lam 2004).
  • Hagen's Bluet (Enallagma hageni)
    Female Hagen's Bluets are similar to Little Bluets, but usually lack a partial pale ring on the base of abdominal segment 8 and differ in mesostigmal plates (Lam 2004).
  • New England Bluet (Enallagma laterale) (guide)
    Female New England Bluets are similar to Little Bluets, but usually lack a partial pale ring on the base of abdominal segment 8 and differ in mesostigmal plates (Lam 2004).

Little Bluet Images

Taxonomy

Little Bluet
Enallagma minusculum Morse, 1895

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

Additional Resources

References

Abbott, J.C. 2007. OdonataCentral: An online resource for the odonata of North America. Austin, Texas. Available at http://odonatacentral.com.

Brown, Virginia. 2005. Surveys of Enallagma minusculum, Enallagma pictum, and Enallagma recurvatum on Long Island, New York: 2005.

Brunelle, P.-M. and P. deMaynadier. 2005. The Maine Dameslfly and Dragonfly Survey: A Final Report. 2nd edition. Report prepared for the Maine Department of Inland Fisheries and Wildlife (MDIFW), Bangor, Maine. November 1, 2005. 31 pp.

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

Donnelly, T.W. 1999. The dragonflies and damselflies of New York. Prepared for the 1999 International Congress of Odonatology and First Symposium of the Worldwide Dragonfly Association. July 11-16, 1999. Colgate University, Hamilton, New York. 39 pp.

Gibbons, L.K., J.M. Reed, and F.S. Chew. 2002. Habitat requirements and local persistence of three damselfly species (Odonata: Coenagrionidae). Journal of Insect Conservation 6:47-55.

Kalkman, V. J., V. Clausnitzer, K. B. Dijkstra, A. G. Orr, D. R. Paulson, and J. van Tol. 2008. Global diversity of dragonflies (Odonata) in freshwater. Hydrobiologia 595:351-363.

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.

NatureServe. 2010. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Data last updated August 2010)

New York Natural Heritage Program. 2011. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

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

New York State Department of Environmental Conservation. 2005. Comprehensive Wildlife Conservation Strategy Planning Database. New York State Department of Environmental Conservation. 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.

White, Erin L., Jeffrey D. Corser, and Matthew D. Schlesinger. 2010. The New York Dragonfly and Damselfly Survey 2005-2009: distribution and status of the odonates of New York. New York Natural Heritage Program, New York State Department of Environmental Conservation. Albany, NY. 450 pp.

Links

About This Guide

This guide was authored by: Erin L. White

Information for this guide was last updated on: June 7, 2011

Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Enallagma minusculum. Available from: https://guides.nynhp.org/little-bluet/. Accessed July 17, 2019.

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