A similar species of  borer moth Canadian Biodiversity Information Facility (CBIF)

A similar species of borer moth
Canadian Biodiversity Information Facility (CBIF)

Insecta (Insects)
Noctuidae (Owlet 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
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.


Did you know?

The Ostrich Fern Borer Moth uses the ostrich fern (Matteuccia struthiopteris) as its only foodplant. The larvae bore into the lower stems and roots of the fern.

State Ranking Justification

Only three occurrences of this species have been documented in New York, with only one of these recently verified. Although the foodplant is fairly common and the species is likely to be more widespread in eastern New York, there is no basis to predict how widespread this moth actually is.

Short-term Trends

The short-term trends are unknown.

Long-term Trends

Probably has lost some habitats, but the original range and abundance are unknown.

Conservation and Management


The most obvious threat is habitat loss to development, agriculture, or to damming and channelization of streams and small rivers. Invasive plants are also a threat in many habitats and mosquito spraying may be a threat, as well. Where this species is occupying multiple small habitat patches as a metapopulation, artificial lights (including bug zappers) operating in the early fall could disrupt necessary movements between these patches (Eisenbeis 2006, Frank 2006). This could cause fern patches where a local colony dies out to remain unoccupied, and this could eventually eliminate the enitre occurrence.

Conservation Strategies and Management Practices

In areas where artificial lighting is necessary, using sodium lights or other low ultraviolet lamps would be beneficial. Controlling invasive plants that threaten ostrich fern (Matteuccia struthiopteris). Monitoring deer herbivory in more upland habitats may also be beneficial. Although deer generally do not severely impact ferns, they sometimes do eat the young fronds in May and, if they eat a lot of the fronds in spring, they would be significant predators on young larvae.



While this species is likely to be most characteristic of floodplain forests, the adults and larvae can turn up in any forested or edge habitat in which ostrich fern is widespread or at least locally abundant. In New York, the ostrich fern borer and the bracken borer (P. pterisii) will seldom or never occur together, but they occur together in parts of Vermont.

Associated Ecological Communities

  • Floodplain forest* (guide)
    A hardwood forest that occurs on mineral soils on low terraces of river floodplains and river deltas. These sites are characterized by their flood regime; low areas are annually flooded in spring, and high areas are flooded irregularly. * probable association but not confirmed.


New York State Distribution

The range in New York includes Albany, Rensselaer, and Columbia Counties, but it is likely to be more widespread in eastern New York, probably in most drainages with an abundance of ostrich fern (Matteuccia struthiopteris). This species does not occur much farther west as far as known.

Global Distribution

This species is known mostly in a narrow band from the Ottawa area south through Vermont where it is widespread, western Massachusetts and the adjacent New York counties, into Connecticut; with one collection each in extreme northern Pennsylvania and southern Wisconsin. The eastern limit appears to be the Connecticut River Valley.

Identification Comments

Identifying Characteristics

This species is similar to the Bracken Borer (Papaipema pterisii). The adults are generally larger and more richly colored than P. pterisii, and are often still fresh in late September to mid-October.

Characters Most Useful for Identification

The adults must be identified from an actual specimen, not from a field photograph. Some worn adults might not be identifiable, but a series of two or three specimens would aid in the identification. The adults are more richly colored, particularly the brown areas are darker, than almost all specimens of the Bracken Borer (Papaipema pterisii). Most adults of the Ostrich Fern Borer are also larger, compared to the Bracken Borer (Papaipema pterisii) and bracken fern will often be absent, which would also likely rule out the Bracken Borer. The collection date could also be a clue, as this species could still be fresh in late September when the Bracken Borer have become quite worn, or in October when the Bracken Borer would be unlikely at all. The larvae should be reared to adults to be sure, but should be separable from the Sensitive Fern Borer Moth (Papaipema inquaesita) by the lack of extensive pink on the thorax and from Sthenopis auratus (McCabe and Wagner 1989) by the much more prominent brown tubercles and much better developed prolegs. Also S. auratus larvae would probably be much smaller than Papaipema larvae in late summer, since the Hepialid larvae mature in June. S. auratus larvae also line their burrow with silk.

Best Life Stage for Proper Identification

Either adults or larvae could be identified, but only by an expert.


The adults are nocturnal, come readily to blacklights, and most likely appear a couple of hours after sunset.


The larva bore in the lower stems and later roots of the ostrich fern (Matteuccia struthiopteris) and use no other plants. The adults probably feed very little, if at all.

Best Time to See

The adults emerge mostly after the bracken borer (P. pterisii) and some ostrich fern borers will be fresh as late as mid-October. Several of this species were collected in Columbia County on September 30, 1989. They probably emerge earliest northward. In general, adults should be looked for from about mid or late September to mid-October, but a few emerge earlier, possibly even in late August, but this would be rare. It is not known when the eggs hatch. Fully fed larvae usually remain dormant for a few weeks before pupating.

  • Reproducing
  • Larvae present and active
  • Eggs present outside adult
  • Pupae or prepupae present

The time of year you would expect to find Ostrich Fern Borer Moth reproducing, larvae present and active, eggs present outside adult, and pupae or prepupae present in New York.

Similar Species

  • Bracken Borer Moth (Papaipema pterisii)
    The adults are generally smaller and less richly colored than the ostrich fern borer moth.

Ostrich Fern Borer Moth Images


Ostrich Fern Borer Moth
Papaipema sp. 2 nr. pterisii None

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

Comments on the Classification

While this species has been known to be distinct since the 1950s, it still has never been formally described. It is listed by Grehan et al. (1995) for Vermont, and listed and briefly discussed and illustrated by Handfield (1999) for Canada.

Additional Resources


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

Eisenbeis, Gerhard. 2006. Artifical night lighting and insects: attraction of insects to streetlights in a rural setting in Germany. Pp. 281-304 in Rich, Catherine and Longcore, Travis (eds.) Ecological Consequences of Artificial Night Lighting. Island Press, Washington, covelo, London. 458 pp.

Frank, Kenneth. 2006. Effects of artifical night lighting on moths. Pp. 305-344 in Rich, C. and Longcore, T. (editors.) Ecological Consequences of Artificial Night Lighting. Island Press, Washington, covelo, London. 458 pp.

Grehan, John R, B. Parker, G. Nielsen, D. Miller, J. Hedbor, M. Sabourin, M.S. Griggs. 1995. Moths and butterflies of Vermont (Lepidoptera): a Faunal List. Univ. VT, Agric. Expt. Sta. and Dept. of Forest, parks and Recreation Misc. publ. 116, Vermont Monitoring Cooperative Bull, no.1. 94 pp. and 4 color plates

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

McCabe, T. L. & D. Wagner. 1989. The biology of Sthenopis auratus Grote (Lepidoptera: Hepialidae). Journal of the New York Entomological Society. 97(1): 1-10.

New York Natural Heritage Program. 2021. New York Natural Heritage Program Databases. Albany, NY.

Quinter, Eric L. Entomology, American Museum of Natural History, New York, NY


About This Guide

Information for this guide was last updated on: December 17, 2012

Please cite this page as:
New York Natural Heritage Program. 2021. Online Conservation Guide for Papaipema sp. 2 nr. pterisii. Available from: https://guides.nynhp.org/ostrich-fern-borer-moth/. Accessed April 11, 2021.

Back to top