Northern Oak Hairstreak

Transcription

1 Northern Oak Hairstreak Oak Hairstreak Scientific Name Family Name Satyrium favonius ontario (W. H. Edwards, 1868) Lycaenidae Blues, Coppers, Hairstreaks, Elfins Did you know? In New York, the northern oak hairstreak occurs in the lower Hudson Valley and on Long Island. It has likely been extripated from the Ithaca area since Photo credits: Erik Nielson Summary Protection Not listed in New York State, not listed federally. This level of state protection means: The species is not listed or protected by New York State. Conservation and Management Threats The main threat is habitat loss. Gyspy moth (Lymantria dispar) spraying with chemical biocides such as Dimilin would severely threaten any occurrence. It is likely, but not known for sure, that Bt (Bacillus thuringiensis - a bacterial biological control used on gypsy moth caterpillars) would also be lethal to the larvae, but it is likely that Bt mortality would be lower than from Dimilin. The larvae normally complete feeding well before defoliation of oaks by gypsy moth larvae would be a threat. Collecting is not a threat, as it would be nearly impossible to overcollect this secretive species. Conservation Strategies and Management Practices In some cases managers might want to consider making sure there are nectar sources available. Milkweeds and dogbanes should not be mowed during their flowering period, but otherwise the habitat is generally forest that probably needs little management. Unless documented otherwise, it must be assumed that Bt is highly lethal to the larvae and NYNHP Conservation Guide - Northern Oak Hairstreak (Satyrium favonius ontario)

2 therefore gypsy moth spraying could eradicate populations. Research Needs Habitat More reserach is needed that would identify which species of oaks the larvae eat and whether or not they have any other special needs. It would also be very useful to document the sensitivity of the larvae to realistic doses of Bt (Bacillus thuringiensis - a bacterial biological control used on gypsy moth caterpillars) such as are applied for gypsy moth suppression. The available evidence for other butterflies in the subfamily Theclinae suggests that this species would be sensitive to Bt (Schweitzer 2004; Wagner et al. 1996), but sensitivity of caterpillars to Bt is very variable, even among species in the same genus (Peacock et al. 1998). This species is most often found on dry rocky or sandy oak or oak-pine forest. Pitch pine and scrub oak may be present, but this butterfly is not generally found in classic pine barrens habitats. It may also turn up around more mixed forests. Associated Ecological Communities Other Probable Associated Communities Pitch pine-oak forest Identification Comments An average size brown hairstreak, occurring in early summer, with a green slug-like caterpillar occurring on oaks in the spring. In New York, this is most likely to be confused with the gray hairstreak. The Northern Oak Hairstreak is a much browner species and the adults are illustrated in virtually any butterfly guide. Characteristics Most Useful for Identification Note the inwardly pointed "v" mark next to the largest white spot on the hindwing beneath and the prominent "M" (or "W") formed by the inner most line. These two markings together should be diagnostic. There is never any blue above. Live individuals always land with the wings closed. The flight season is also a clue to species, as this species will only be seen in or near New York in June and about the first half of July. Best Life Stage for Identifying This Species This should be identified as an adult, but an expert on hairstreaks might be able to identify the larva. See Allen et al. (2005). NYNHP Conservation Guide - Northern Oak Hairstreak (Satyrium favonius ontario) 2

3 Present Reproducing Larvae present and activ Eggs present outside adu Behavior Diet Adults seem to come to flowers most often late in the day and are thought to spend most of their time in the oak canopy. Adults occasionally are caught in blacklight traps in places where they are otherwise not known to occur. The larvae are oak feeders, but exactly which species of oaks they use is largely unknown. They do not seem to be particularly associated with scrub oak, but they might use it where it is available. Larvae feed on the new spring growth only and the adults will visit a number of species of flowers, but are most often seen on common milkweed (Asclepias syriaca) and dogbane(apocynum sp.). Dale Schweitzer has found them on maleberry (Lyonia ligustrina) flowers in New Jersey. The Best Time to See The adults occur for less than a month in any given year, from about mid-june into mid-july. They often start a few days earlier than the other single-brooded early summer hairstreaks, but commonly occur with the others. The eggs overwinter on oaks and the larvae feed on the new growth in spring, probably finishing about the first of June in most years. There is only one brood in all parts of the range of this species. The adults visit flowers most often late in the day, usually after 16:00 hours. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec The time of year you would expect to find Northern Oak Hairstreak in New York. Conservation Comments This species is usually placed in the genus Satyrium, currently. Older works considered northern populations (subspecies ontario) as a separate species. Taxonomy Kingdom Phylum Animalia Mandibulates (Mandibulata) Class Insects (Insecta) Order Butterflies, Skippers, and Moths (Lepidoptera) Family Lycaenidae (Blues, Coppers, Hairstreaks, Elfins) NYNHP Conservation Guide - Northern Oak Hairstreak (Satyrium favonius ontario) 3

4 Synonyms Fixsenia favonius ontario Additional Resources Links NatureServe Explorer ONTARIO Google Images References Allen, T.J., J.P. Brock, and J. Glassberg Caterpillars in the field and garden. Oxford University Press, New York. 232 pp. Brock, J. P., and K. Kaufman Butterflies of North America. Kaufman Focus Field Guides, Houghton Mifflin Company, New York, NY 284 pp. Glassberg, J Butterflies through binoculars: A field guide to butterflies in the Boston-New York-Washington region. Oxford University Press: New York. 160 pp. Glassberg, J Butterflies Through Binoculars: The East. Oxford University Press, New York, New York. 400 pp. Gochfeld, M. and J. Burger Butterflies of New Jersey. Rutgers University Press: Rutgers, New Jersey. 327 pp. Iftner, D. C., J. A. Shuey, and J. V. Calhoun Butterflies and Skippers of Ohio. Ohio Biological Survey Bulletin. New Series, Vol. 9, no. 1, xii pp., 40 color plates. Keys, Jr.,J.; Carpenter, C.; Hooks, S.; Koenig, F.; McNab, W.H.; Russell, W.;Smith, M.L Ecological units of the eastern United States - first approximation (cd-rom), Atlanta, GA: U.S. Department of Agriculture, Forest Service. GIS coverage in ARCINFO format, selected imagery, and map unit tables. NatureServe NatureServe Central Databases. Arlington, Virginia. USA O'Donnell, J.E., L.F. Gall., and D.L. Wagner, eds The Connecticut Butterfly Atlas. State Geological and Natural History Survey of Connecticut, Department of Environmental Protection, Hartford. 376 pp. Opler, P. A., and A. D. Warren Butterflies of North America. 2. Scientific Names List for Butterfly Species of North America, north of Mexico. C.P. Gillette Museum of Arthropod Diversity, Department of Bioagricultural Sciences and Pest Management, Colorado State University, Fort Collins, Colorado. 79 pp. Peacock, J. W., D. F. Schweitzer, J. L. Carter, and N. R. Dubois Laboratory Assessment of the effects of Bacillus thuringiensis on native Lepidoptera. Environmental Entomology 27(2): Schweitzer, Dale F Gypsy Moth (Lymantria dispar): impacts and options for biodiversity-oriented land managers. NatureServe, Arlington, Virginia. NatureServe Explorer. Online. Available: NYNHP Conservation Guide - Northern Oak Hairstreak (Satyrium favonius ontario) 4

5 Shapiro, A.M Butterflies and Skippers of New York State. Search 4:1-60. Wagner, D.L., J.W. Peacock, J.L. Carter, and S.E. Talley Field assessment of Bacillus thuringiensis on nontarget Lepidoptera. Environmental Entomology 25(6): New York Natural Heritage Program 625 Broadway, 5th Floor, Albany, NY Phone: (518) This project is made possible with funding from: - New York State Department of Environmental Conservation Hudson River Estuary Program - Division of Lands & Forests, Department of Environmental Conservation - New York State Office of Parks, Recreation and Historic Preservation Information for this guide was last updated on Aug 10, 2017 This guide was authored by NYNHP Conservation Guide - Northern Oak Hairstreak (Satyrium favonius ontario) 5