Tawny Emperor Steve Walter

Tawny Emperor
Steve Walter

Class
Insecta (Insects)
Family
Nymphalidae (Brushfooted Butterflies)
State Protection
Not Listed
Not listed or protected by New York State.
Federal Protection
Not Listed
State Conservation Status Rank
S2S4
Imperiled or Vulnerable in New York, or Apparently secure - Conservation status is uncertain; could be very vulnerable, or vulnerable, to disappearing from New York due to rarity or other factors, or could be uncommon but not rare in New York. More information is needed to assign either S2, S3 or S4.
Global Conservation Status Rank
G5
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).

Summary

Did you know?

Tawny Emperor larvae hibernate in the leaf litter under hackberry (Celtis spp.) plants.

State Ranking Justification

This species has a limited range in New York. It is likely a permanent resident in southeastern New York, although individual colonies can be transient. Its status is uncertain elsewhere.

Short-term Trends

The short-term trends are unknown, although this species could increase or stabilize with a warming climate.

Long-term Trends

The long-term trends are unknown.

Conservation and Management

Threats

The threats include habitat destruction, leaf raking, and Gyspy Moth (Lymantria dispar) spraying. Larvae of this species were documented to be highly sensitive to Bt (Bacillus thuringiensis - a bacterial biological control used on Gypsy Moths) (Peacock et al. 1998). Like many gregarious species, population numbers can fluctuate greatly, partially due to parasitism, and small colonies may not persist in some years. Cold winters without snow cover might also eliminate populations in New York.

Conservation Strategies and Management Practices

Leaf litter under hackberries (Celtis spp.) should be left undisturbed from mid-August into May since the larvae spend most of the year hibernating there (Dale Schweitzer).

Habitat

Habitat

This species is potentially found in any shaded habitat that contains hackberry (Celtis spp.). Although it does not require pristine habitat, it would would not be likely to be found on lawns. Shapiro (1974) indicates that habitats are generally bottomlands in New York.

Associated Ecological Communities

  • Calcareous cliff community (guide)
    A community that occurs on vertical exposures of resistant, calcareous bedrock (such as limestone or dolomite) or consolidated material; these cliffs often include ledges and small areas of talus.
  • Limestone woodland (guide)
    A woodland that occurs on shallow soils over limestone bedrock in non-alvar settings, and usually includes numerous rock outcrops. There are usually several codominant trees, although one species may become dominant in any one stand.

Associated Species

  • Hackberry Emperor (Asterocampa celtis)

Range

New York State Distribution

This species has been found in the southern counties as far north as Tompkins County. It turns up most often in the southeastern Hudson Valley counties near New York City, including Long Island. This species can be reliably seen in some places (Shapiro 1974, Glassberg 1993) and is almost certainly a permanent resident in southeastern New York, although individual colonies can be transient. Its status is uncertain elsewhere. The range could expand with a warming climate.

Global Distribution

As the species is now defined, it occupies most of the range of the eastern hackberries (Celtis spp.), from Connecticut to southern Minnesota south through most of Florida and Texas and well into Mexico, west through northern Mexico and southeastern Arizona (Brock and Kaufman 2003).

Identification Comments

Identifying Characteristics

Adults are easily identified at least if the upper side is seen. See any butterfly book. Larvae can also be separated. This species lays its eggs in large masses often two layers deep on the underside of hackberry leaves. These can often be identified by Lepidopterists. A. celtis lays eggs singly or nearly so.

Characters Most Useful for Identification

The general color and details of the pattern are easily identifiable. See any butterfly guide. The larvae can be identified by the characters given by Wagner (2005) and Allen et al. (2005). The eggs are laid in large masses, often two layers deep, on the underside of hackberry (Celtis spp.) leaves. It should be noted, however, that there are some other moths, notably several Arctiidae, that may lay egg masses on hackberry.

Best Life Stage for Proper Identification

The larvae and adults can be identified from available books and the eggs can be identified by an expert.

Behavior

The males are most active earlier in the day than the more common Hackberry Emperor (Asterocampa celtis). The larvae are gregarious, except in the late instars, and multiple individuals may be found in a slightly rolled leaf.

Diet

The larvae feed only on various species of hackberry (Celtis spp.). The adults rarely visit flowers and their true feeding habits are not well known. They can be seen visiting sap oozes, fermenting fruits, and moist soil.

Best Time to See

The main flight season in New York is July, although Glassberg (1993, 1999) indicates a few individuals in June, August, and September. The species has two or more annual broods through most of its range. The larvae hibernate in the third instar, which is probably reached in August, although a few continue development to produce a partial second brood. Second brood larvae enter hibernation in October (in New Jersey), but it is uncertain how late into the fall overwintering progeny of July adults remain active. The related A. celtis can enter winter diapause, also as third instar larvae, anytime from early July to October in New Jersey (D.Schweitzer) making both its second and third broods partial there. The larvae resume feeding in spring soon after the new leaves begin to appear, but the July flight season suggests they may not resume feeding until about mid or late May in New York. During warm weather, the pupal stage should take no more than two weeks.

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

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

Tawny Emperor Images

Taxonomy

Tawny Emperor
Asterocampa clyton (Boisduval and Le Conte, [1835])

  • Kingdom Animalia
    • Phylum Mandibulata (Mandibulates)
      • Class Insecta (Insects)
        • Order Lepidoptera (Butterflies, Skippers, and Moths)
          • Family Nymphalidae (Brushfooted Butterflies)

Additional Resources

References

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.

Glassberg, J. 1993. Butterflies through binoculars: A field guide to butterflies in the Boston-New York-Washington region. Oxford University Press: New York. 160 pp.

Glassberg, J. 1999. Butterflies Through Binoculars: The East. Oxford University Press, New York, New York. 400 pp.

Gochfeld, M. and J. Burger. 1997. Butterflies of New Jersey. Rutgers University Press: Rutgers, New Jersey. 327 pp.

Iftner, D. C., J. A. Shuey, and J. V. Calhoun. 1992. Butterflies and Skippers of Ohio. Ohio Biological Survey Bulletin. New Series, Vol. 9, no. 1, xii + 212 pp., 40 color plates.

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

O'Donnell, J.E., L.F. Gall., and D.L. Wagner, eds. 2007. The Connecticut Butterfly Atlas. State Geological and Natural History Survey of Connecticut, Department of Environmental Protection, Hartford. 376 pp.

Peacock, J. W., D. F. Schweitzer, J. L. Carter, and N. R. Dubois. 1998. Laboratory Assessment of the effects of Bacillus thuringiensis on native Lepidoptera. Environmental Entomology 27(2):450-457.

Shapiro, A.M. 1974. Butterflies and Skippers of New York State. Search 4:1-60.

Wagner, D.L. 2005. Caterpillars of eastern North America. Princeton University Press. Princeton, New Jersey. 512 pp.

Links

About This Guide

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

Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Asterocampa clyton. Available from: https://guides.nynhp.org/tawny-emperor/. Accessed September 23, 2019.

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