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DELAWARE PHOTURIS FIREFLIES (COLEOPTERA: LAMPYRIDAE): NEW STATE RECORDS, CONSERVATION STATUS, AND HABITAT ASSOCIATIONS1 Christopher M. Heckscher2
ABSTRACT: In the Middle-Atlantic region, the distribution, abundance, and habitat associations of fireflies in the genus Photuris are poorly understood. Six species in Photuris are recorded from Delaware. Ten years (1998-2008) of periodic survey work has yielded three new state records and contributed valuable information regarding species abundance and habitat affiliations in this region. Results from that survey are summarized and compared to previously published Delaware records. This is the first concerted effort to report the conservation status and the associated habitat and natural community types of Photuris fireflies from the Middle-Atlantic region. KEY WORDS: Conservation status, Delaware, Lampyridae, Middle-Atlantic region, Photuris, fireflies, habitat associations, natural community associations
INTRODUCTION A paucity of published information exists regarding the distribution and conservation status of Middle-Atlantic species in the Lampyridae genus Photuris (e.g., Barber, 1951; McDermott, 1967; Downie and Arnett, 1996). Further, spec ies’ habitat affiliations are unpublished or insufficiently described for most species despite the fact that identifications can be simplified with knowledge of associated habitat or surrounding natural communities (i.e., plant community or ecosystem types). Those shortcomings in part reflect geographically limited survey effort and confusing taxonomic keys. McDermott (1958) reported six species in the genus Photuris from Delaware and supplied only vague habitat descriptions for some species. Here I report the results from ten years of field surveys in Delaware (1998-2008). These surveys have provided three new state records, the discovery of a species previously unknown to science, and important information about the occurrence of species in various natural community types in this region. I also report the general location of collection sites and provide brief comments regarding observed habitat associations and the overall rarity of species encountered since 1998 including those previously reported by McDermott. The distribution and habitat associations of P. bethaniensis McDermott were recently summarized by Heckscher and Bartlett (2004) and are not discussed in detail. Known published distribution records are included where appropriate. However, specimens that were reported prior to Barber’s revision of the genus in 1951 and not included as part of that effort, should be re-examined and are not noted here. ______________________________ 1 2
Received on July 20, 2010. Accepted on December 30, 2010.
Delaware State University, Department of Agriculture and Natural Resources, 1200 N. DuPont Highway, Dover, Delaware 19901. Phone (302) 857-6412. E-mail:
[email protected] Mailed on February 2, 2012
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METHODS At each collection site, adult fireflies were captured with a sweep net and immediately placed in collecting vials with 70% isopropyl alcohol. A description of the flash pattern of the individual prior to capture, perceived color of the flash, surrounding physical environment, and associated plant community descriptions were immediately noted in field books. These habitat features were recorded from the locations in which individuals were seen emerging and signaling. Soon after capture, specimens were removed from vials and mounted on insect pins. Specimens were then identified with the assistance of the following keys recognizing Lloyd’s (2001) working species concept: Barber (1951), McDermott (1967), Downie and Arnett (1996). Despite these keys, many species of the genus Photuris are notoriously difficult to confidently identify to species-level because of similarity and variation in their morphology including that of published diagnostic characters; thus, for that reason Lloyd (2002; pers. comm.) specifically noted that neither Barber (1951), McDermott (1967), or Downie and Arnett (1996), are solely reliable. Flash pattern can be as important as morphological characteristics when separating species (Lloyd, 1969; pers. comm.). Therefore, for final determinations reported here, observations regarding flash pattern and associated habitat were considered crucial. Identified specimens were then compared with those labeled in J. E. Lloyd’s private voucher collection. Some specimens were also compared to those determined by F. A. McDermott which are presently located at the University of Delaware Insectary, Newark. During this ten-year period, specimens that were obtained haphazardly or donated to this survey effort by colleagues without the accompanied information regarding flash pattern and habitat, are not reported. General conservation status was inferred for each species by considering the distribution of collection sites and the known distribution of the species’ associated habitat type in Delaware. For example, a species could be considered rare if it was rarely found in a widespread and common habitat type or if it was common in a rare habitat type. All specimen records presented below are represented by vouchers in the author’s collection currently located at Delaware State University, Dover. Unless otherwise noted the author collected all reported specimens. Specimens designated with (PD) were collected on the Middle-Atlantic Appalachian Piedmont physiographic province while all others were collected from the Middle-Atlantic Coastal Plain physiographic province. RESULTS AND DISCUSSION McDermott (1958) listed six species in the genus Photuris known from Delaware: P. bethaniensis, P. hebes Barber, P. lucicrescens Barber, P. pensylvanica (DeGeer), P. salina Barber, P. versicolor (Fabricius). Here, I report updates for all but P. bethaniensis and summarize three new state records: P. frontalis LeConte, P. pyralomima Barber, P. cinctipennis Barber. The following updates
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and summaries include the specimens examined and brief notes regarding known distribution in this region, associated habitat, and current Delaware conservation status. Associated habitats and conservation status of all recognized Delaware species are summarized in Table 1. In addition, two undescribed Photuris species are present in Delaware but are not included in this report (P. “BBB” [Lloyd 2001b] and P. “SPH” recently discovered by the author). Table 1. Species in the Lampyridae genus Photuris recorded from Delaware with associated habitat, natural community association, and Delaware conservation status.
Species
Associated Habitat and Natural Community Association
Delaware Status
P. frontalis
Well-drained semi-xeric forests with Carya pallida
Uncommon
P. bethaniensis
Freshwater interdunal swales1
Rare
P. pensylvanica
High quality freshwater emergent, shrub, and floodplain peatlands
Uncommon
P. versicolor
Variety of habitats but usually found occupying forest or scrubshrub vegetation
Common
P. pyralomima
Open habitats including moist meadows and scrub-shrub vegetation
Common
P. lucicrescens
Forested floodplains and adjacent upland forest including urban areas
Locally common
P. hebes
Undisturbed freshwater emergent wetlands, moist meadows, roadside depressions, and forested floodplains
Uncommon
P. salina
Drier portions of brackish coastal marshes
Rare
P. cinctipennis
Moist floodplain forests
Rare
1
Heckscher and Bartlett (2004)
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Photuris frontalis LeConte. SUSSEX COUNTY: 13 Jun 2002, Nanticoke State Wildlife Area, N. of Broad Creek, two specimens; 17 Jun 2004, Prime Hook National Wildlife Refuge, two specimens; 28 Jun 2007, Stockley Center (Doe Bridge) Nature Preserve, upland forest west side of Cow Bridge Branch, three specimens. Barber (1951) reports P. frontalis from Anne Arundel and St. Mary’s counties in Maryland and from Georgia. Both Barber (1951) and McDermott (1967) note that this species is found around the lower branches of trees. In Delaware, all three collection sites were well-drained, semi-xeric, sandy, pine-oak-hickory woodlands that include Carya pallida Engl. & Graebn. The sporadic but widespread distribution of this forest community type suggests that P. frontalis may be locally common in Sussex County. Photuris frontalis has not been reported from Kent or New Castle Counties where this forest community type is rare or absent. Photuris pyralomima Barber. NEW CASTLE COUNTY: 21 Jun 2007, Brandywine Creek State Park, three specimens, (PD); KENT COUNTY: 21 Jun 2005, Bombay Hook National Wildlife Refuge, four specimens; 7 Jun 2007, Woodland Beach State Wildlife Area, four specimens; SUSSEX COUNTY: 17 Jun 2004, Prime Hook National Wildlife Refuge, one specimen; 6 Jun 2005, Prime Hook National Wildlife Refuge, one specimen; 21 Jun 2005, Prime Hook National Wildlife Refuge, one specimen. Published records of this species are limited to Albany County, New York (Barber 1951). This species has been associated with hayfields (Barber, 1951; McDermott, 1967). However, in Delaware it was collected from other open habitat types including dense shrubby fields and moist meadows. Photuris pyralomima was found in all three Delaware counties. Photuris cinctipennis Barber. KENT COUNTY: 17 & 24 Jul 2001, 0.75 km N of Dinah’s Corner, two specimens (col. R. F. Naczi); 1 Jul 2004, Causeway Br., Milford Neck State Wildlife Area, one specimen (sympatric with P. hebes). This species has been reported from Anne Arundel and St. Mary’s counties in Maryland (Barber 1951). In July 2004, this species was abundant along Cause way Branch near the Delaware Bay coast. Individuals were signaling from moist forested floodplain habitat. That habitat affiliation is consistent with that reported by McDermott (1967) as “stream sides.” The other two reported specimens were captured six days apart at an incandescent light placed in the same location on consecutive nights in a semi-urban landscape near a forested floodplain. McDermott (1958) did not report this species from Delaware and it was only collected at two sites during this survey – an indication of its rarity in the state.
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Updates to known Delaware species
Photuris pensylvanica (DeGeer). SUSSEX COUNTY: 3 & 17 Jun 2004, Prime Hook National Wildlife Refuge, four specimens; 21 Jun 2005, Prime Hook National Wildlife Refuge, freshwater “bog,” two specimens; 28 Jun 2007, Doe Bridge Nature Preserve, Cow Marsh Creek “bog,” one specimen; 16 Jul 2008, Doe Bridge Nature Preserve, Cow Marsh Creek “bog,” one specimen. In the Mid-Atlantic region, this species is known from Delaware, Pennsylvania, New Jersey, Maryland, and the District of Columbia (Barber, 1951; McDermott, 1967). Barber (1951) reported this species from tidal marshes of the Potomac and Patuxent River. McDermott (1967) reported that this species is associated with “tall grass” and “…swampy areas or near them.” The 2004 specimens included here were collected from a dense non-tidal freshwater shrub swamp with deep peat, sphagnum, and dense emergent herbaceous vegetation and were observed giving the diagnostic two-part flash pattern (see Barber, 1951; McDermott, 1967). The 2005, 2007, and 2008 specimens were collected from acidic freshwater seepage fens (“bogs”) of high ecological quality and were observed giving a single bright flash pattern at their respective locations. The diagnostic two-part flash pattern was observed at two other sites that lack voucher specimens: an emergent tidal freshwater marsh along Hangman’s Run S. of Odessa, New Castle Co., (Delaware Bay estuary) and from freshwater tidal acidic seepage forests along both sides of the Nanticoke River south of Woodland, Sussex Co., (Chesapeake Bay estuary). Based on these observations P. pensylvanica is associated with high quality tidal and non-tidal freshwater wetlands including shrub and forest acidic seepage swamps, emergent marsh, and fens. Interestingly, McDermott (in Barber 1951) suggested this species had disappeared from areas in northern Delaware prior to 1951 due to the loss and contamination of freshwater marshes. Locally, the species may be regarded as an environmental indicator of high quality freshwater wetlands; indeed, it is now uncommon in Delaware probably because of its apparent association with undisturbed natural areas. Photuris versicolor (Fabricius). NEW CASTLE COUNTY: 22 Jul 2004, Ashland, Red Clay Creek floodplain, one specimen, (PD); 9 Jul 2005, White Clay Creek State Park, three specimens, (PD); 21 Jun 2007, Brandywine Creek State Park, two specimens, (PD). KENT COUNTY: 7 Jun 2007, Woodland Beach, Rte. 9, two specimens. SUSSEX COUNTY: 25 Jul 1998, Fenwick Island State Park, E. of Rte. 1, one specimen. This species was collected in all three counties from fields, floodplain forests, and upland forests. Barber (1951) reports this species primarily from fields but also forest. It appears to be a habitat generalist throughout the Mid-Atlantic region and is among Delaware’s most common Photuris species.
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Photuris lucicrescens Barber. NEW CASTLE COUNTY: 16 Jun 2004, White Clay Creek State Park, two specimens, (PD); 2 Jul 2004, Leatherman’s Run, Woodshade dev., one specimen; 27 Jul 2004, Ashland, Red Clay Cr. floodplain, one specimen, (PD); 28 Jun 2005, White Clay Creek State Park, one specimen, (PD); KENT COUNTY: 1 Jul 2004, Beaverdam Br., 6 km NE of Milford, one specimen; 19 Jul 2007, Blackbird State Forest, Tyabout Tract, two specimens; SUSSEX COUNTY: 29 Jul 2004, Prime Hook National Wildlife Refuge, one specimen; 6 Jul 2005, Prime Hook National Wildlife Refuge, one specimen; 12 Jul 2005, Nanti coke State Wildlife Area, Phillips Landing trail, three specimens; 10 Jul 2008, Nanticoke State Wildlife Area, Phillips Landing Trail, three specimens; 12 Jul 2007, Angola Neck, two specimens. In this region, Photuris lucicrescens has been reported from Delaware, Maryland, Virginia, and the District of Columbia (Barber, 1951; McDermott, 1967). This species has been associated with forest (Barber 1951) and more specifically with trees along streams (McDermott, 1967). During this survey it was found occupying forested floodplains and flying in adjacent upland areas including forests and a housing development. It is widespread and seems secure in Delaware. Photuris hebes Barber. KENT COUNTY: 20 Jul 2001, Woodland Beach Wild life Area, four specimens (col. K. S. Kalasz); 1 Jul 2004, 1 km W of Big Stone Beach, two specimens; 1 Jul 2004, Causeway Br., Milford Neck Wildlife Management Area, two specimens (sympatric with P. cinctipennis); SUSSEX COUNTY: 14 Jul 1998, Delaware Seashore State Park, E. of Rte 1, three specimens (det. J. E. Lloyd); 8 Jun 2000, Cape Henlopen State Park, freshwater interdunal wetland on the Henlopen Point, one specimen. This species has been reported from Delaware, Maryland, and Virginia (Barber, 1951; McDermott, 1967). Barber (1951) reported this species from Baccharis shrubs and tall grass bordering a salt water wetland. McDermott (1967) reported that this species is associated with “willow-covered fresh-water wetlands” and “fields and around trees.” During this survey period, this species was found in a variety of plant community and habitat types including emergent freshwater wetlands, moist meadows, roadside depressions, interdunal freshwater swales, floodplains, and Baccharis shrubs bordering a brackish marsh. McDermott (1967) remarked that the species is common in northern Delaware. Although this species occurs sporadically in suitable habitat, it was not common in any portion of the state. The flash pattern of P. hebes is rapid and single, usually given from within areas dominated with herbaceous wetland vegetation. From a distance, through hazy environmental conditions, the flash color of P. hebes can appear orange (Downie and Arnett 1996). That signal has been observed in suitable habitat at two additional locations during this survey period: emergent freshwater tidal marshes bordering Broad Creek, Sussex County, and a wetland mitigation site near the jct. of Old Baltimore Pike and Salem Church Road, Newark, New Castle County.
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Photuris salina Barber. KENT COUNTY: 20 Jul 1999, Woodland Beach Wildlife Management Area, Rte. 9, two specimens; 28 Jul 1999, Woodland Beach Wildlife Management Area, Rte. 9, four specimens. Barber (1951) and McDermott (1958, 1967) reported this species from drier portions of Baccharis-Spartina patens brackish marshes. This species has been collected in Delaware (McDermott 1958, 1967); however, although many remote coastal marshes were not explored during this survey, P. salina must be considered to have become less common in Delaware since McDermott’s time. During the current survey period it was found at only one site at Woodland Beach Wildlife Area. In the intervening decades since McDermott was actively collecting, aerial application of adulticides and larvacides for mosquito control, burning to control the spread of the invasive Phragmites australis, and sea-level rise, are some events that have affected the ecology of most coastal brackish marshes in Delaware. This species has been formerly reported from high brackish marshes in the Chesapeake Bay estuary, Maryland (Barber, 1951). Of the thirteen Photuris species known from the Mid-Atlantic region (including P. “BBB” and P. “SPH” noted above), two have not been confirmed in Delaware: P. tremulans Barber and P. potomaca Barber. Photuris tremulans is present in this region having been reported from Maryland and Virginia (Barber, 1951) and collected by the author in nearby Delaware County, Pennsylvania, in 2005. However, P. potomaca has only been found along the Potomac River north of the District of Columbia in portions of Maryland and Virginia where it has been reported as locally common (Barber, 1951; McDermott 1967; J. E. Lloyd, pers. comm.). ACKNOWLEDGEMENTS
Some survey work was accomplished in association with cursory surveys of natural areas undertaken by the Delaware Natural Heritage and Endangered Species Program, Delaware Division of Fish and Wildlife. James E. Lloyd provided helpful advice, access to his personal collection, confirmed and determined the identifications of some specimens, and reviewed a draft of this paper. Kevina Vulinec provided helpful editorial advice. William A. McAvoy contributed botanical information. Anthony Gonzon, Kevin S. Kalasz, Lisa Kendall, and Robert F. Naczi assisted with survey work. This paper benefited from the comments of two anonymous reviewers.
LITERATURE CITED
Barber, H. S. 1951. North American Fireflies of the Genus Photuris. Smithsonian Miscellaneous Collections 117:1-58.
Downie, N. M. and R. H. Arnett, Jr. 1996. The beetles of northeastern North America, Volume I. Sandhill Crane Press. Heckscher, C. M. and C. R. Bartlett. 2004. Rediscovery and habitat associations of Photuris bethaniensis McDermott (Coleoptera: Lampyridae). Coleopterist’s Bulletin 58:349-353.
Lloyd, J. E. 1969. Flashes of Photuris fireflies: Their value and use in recognizing species. The Florida Entomologist. 52:29-35.
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Lloyd, J. E. 2001a. On Research and entomological education V: A species (c)oncept for fireflyers, at the bench and in old fields, and back to the Wisconsian glacier. Florida Entomologist 84:588-601. Lloyd, J. E. 2001b. On research and entomological education VI: Firefly species and lists, old and new. Florida Entomologist 86:99-113. Lloyd, J. E. 2002. Lampyridae. Pages 187-196. In, R. H. Arnett Jr., M. C. Thomas, P. E. Skelley, and J. H. Frank, eds., American Beetles, Volume 2. CRC Press, New York.
McDermott, F. A. 1958. The Fireflies of Delaware. Society of Natural History of Delaware. Wilmington, Delaware.
McDermott, F. A. 1967. The North American Fireflies of the genus Photuris DeJean a modification of Barber’s Key (Coleoptera; Lampyridae). Coleopterist’s Bulletin 21:106-116.
