Journal of the North Carolina Academy of Science, 124(4), 2008, pp. 139–147

MORPHOLOGY AND BEHAVIOR OF PHAUSIS RETICULATA (BLUE GHOST )

JENNIFER E. FRICK-RUPPERT* and JOSHUA J. ROSEN Department of Science and Math, Brevard College, Brevard, NC 28712

Abstract: Phausis reticulata, the Blue Ghost Firefly, is a lampyrid found in the southern Appalachians, observed primarily in May and June. Its luminescence is characterized by a steady glow, in contrast to a species-specific pattern of flashes. It is also characterized by a large degree of sexual dimorphism, with a winged male and paedomorphic, apterous female. Both sexes have light organs. Behavior and habitat of P. reticulata were observed at several locations in the southern Appalachians from 1997 through 2008, most intensively in 2006 and 2007. Information was also gathered from preserved specimens in collections. Female anatomy is reported for the first time, and male anatomy is further clarified. Key Words: firefly; lampyrid; Phausis; Appalachians.

INTRODUCTION emission varied between individuals, from ‘‘a few The southeastern United States is widely known for seconds to a minute or more.’’ He described the its diversity of lampyrid species (Lloyd 2004); however, paedomorphic female’s green-white glow as originating many of these species are incompletely known and have from four spots on the abdomen in some individuals, not been subject to extensive study. One of these lesser- but six spots in others. The two additional organs known species is Phausis reticulata, the Blue Ghost Firefly. observed in some females are located in the posterior end and are smaller than the other four; Lloyd suggested P. reticulata was first described by Thomas Say in that these may be larval lights temporarily retained into 1825 as reticulata (Say 1825). The type adulthood (Lloyd 1965; McDermott 1948). specimen was given to Say by botanist Thomas Nuttall Phausis is one of several genera termed ‘‘glowworm after a trip to the Arkansas Territory. J.L. LeConte ,’’ which are characterized by a burrowing, created the Phausis in 1851, with P. reticulata as paedomorphic female who emits light to attract the its first member (LeConte 1851). The genus was last flying male (Lloyd 1971, 1983, 2004; Branham 2003). revised by K.M. Fender in 1966. There are no records in Males of P. reticulata, unlike those of most other the literature of any observation of the eggs, larvae or glowworm fireflies, are luminous. pupae of P. reticulata. P. reticulata is also unusual in that it does not fit In addition to the type locality in Arkansas, P. neatly into the ‘‘signal system’’ classification devised by reticulata was later found in Georgia, Tennessee and Lloyd (1971) to describe communication in fireflies. In Texas (LeConte 1881). K.M. Fender’s specimens were Lloyd’s Signal System I, a stationary female produces a from western North Carolina (Avery County; Cherokee species-specific photic signal to attract the flying male. County), eastern Tennessee (Morgan County), and In Signal System II, the flying male emits a photic signal central Tennessee (Smith County); he reports that the to which the female responds after a brief delay; photic distribution of P. reticulata is centered in the Black signals and delay length are species-specific (Lloyd 1971; Mountains of western North Carolina (Fender 1966). Branham et al. 2003). Lloyd suggested a ‘‘transitional’’ J.E. Lloyd (1965) also found P. reticulata in both system for P. reticulata because females glow to attract western North Carolina (Mt. Pisgah, Buncombe Coun- males (Signal System I) and also illuminate their lights ty) and in eastern Tennessee (Great Smoky Mountains when a male passes overhead (Signal System II) (Lloyd National Park, Sevier County). Lloyd later wrote the 1965, 1966, 1971). Lloyd later replaced the signal system species could be found in ‘‘scattered localities across paradigm with a broader concept that focused on photic North America to Oklahoma, but can be seen in signals, habitat, mating season and other factors (Lloyd abundance in the Appalachian Mountains’’ (Lloyd 2004). 1983; Branham et al. 2003), and his hypothesis that J.E. Lloyd (1965), in the only record of field research signal system II originated from signal system I has not involving P. reticulata, reported that males flew ‘‘in a been supported (Branham et al. 2003). variety of fashions’’; some rapidly, others more slowly. The purpose of this study was to elucidate the Males emitted a bright green glow; the period of light structure of both males and females of Phausis reticulata and to study their behavior. While it was known that the * e-mail: [email protected] females were larviform, their specific anatomy was 139 140 JOURNAL OF THE NORTH CAROLINA ACADEMY OF SCIENCE 124(4) unreported. We compared preferred habitat, seasonal- proximity of water bodies. Precipitation and moonlight ity, nightly activity levels, and density of both males and levels were recorded during site visits in 2006 and 2007. females and hypothesized that since luminescence is Air temperature, soil temperature, relative humidity, air used in sexual signaling, males and females would pressure, rainfall, wind speed, and wind direction were respond to each other and to other light sources prior to recorded in 2006 in DuPont State Forest on two days mating. with different weather conditions to evaluate their effect on P. reticulata behavior. Air and ground temperatures were recorded in 2008 in Balsam Grove. METHODS Behavioral observations of P. reticulata males includ- Several field sites in four states (North Carolina, ed flight speed and height from the ground, density and Tennessee, Georgia and South Carolina) across the pattern of distribution, time of emergence and peak southern Appalachians were utilized. Four sites in NC activity. Observations of the non-flighted females included DuPont State Forest, a 4,200-hectare tract of concentrated on distribution, reaction to stimulus and preserved forest in southeastern Transylvania County intensity/duration of light emission. Collected specimens and southwestern Henderson County at an elevation of were restrained in transparent plastic containers. Reac- 730 m (at the study site); Pink Beds Picnic Area in tions of both males and females to bursts of white, red, Pisgah National Forest, a popular recreational area of and blue light and physical disturbance were recorded. about 400 hectares at 1,000 m elevation in northeastern Two females (2006, DuPont State Forest) were placed Transylvania County; Sherwood Forest, a private 400- separately in small, shallow, transparent containers hectare community in Cedar Mountain, southeastern nestled into the leaf litter to experimentally observe Transylvania County, 880 m elevation; and a private, male/female interaction. These females were later placed 32-hectare tract in Balsam Grove in northern Transyl- directly into the leaf litter. Mating under natural vania County at 915 m. conditions was also observed (DuPont State Forest Two sites in TN were located in Great Smoky and Balsam Grove). Four males (2006, DuPont State Mountains National Park (GSMNP) and both were at Forest) were placed into small plastic containers and 580 m elevation: Porters Creek Trail (Sevier County), kept in the dark at constant temperature overnight in located in the Greenbrier area of the park, and Middle order to evaluate circadian rhythms. They were ob- Prong Trail (Blount County) in the Tremont area of the served every few hours. park. Warwoman Dell Recreation Area in GA falls In addition to specimens collected at the different field within the Chattahoochee National Forest in central sites, we also examined those in the insect collections of Rabun County near Clayton at 500 m elevation. Asbury Brevard College, Clemson University, University of Hills in SC, examined in 2007, is a 730-hetare camp and Georgia, and North Carolina State University. We retreat center at 365 m elevation located in northwestern accessed the database of the All Taxa Biodiversity Greenville County near Cleveland. Cleveland is host to Inventory for the Great Smoky Mountains National an annual viewing event of the Blue Ghosts on Park and downloaded its information on collection 50 hectares of private land owned by Mr. Don Lewis locations, but were not shipped specimens. The insect and is located at 307 m elevation. Lloyd’s collection site collections of Virginia Tech, Virginia Museum of at the base of Mt. Pisgah in Buncombe County, NC, Natural History and University of Tennessee-Knoxville specifically the trailhead at the parking area, was visited did not have any specimens of P. reticulata. on 8 June 2008. Microscopic examination of specimens was per- Initial observations and identification of P. reticulata formed using a Wild-M5 microscope and drawings were began in May and June of 1997 in Balsam Grove, NC. completed with the aid of a camera lucida. A Sony One of us (J. Frick-Ruppert) collected and observed High-Definition-Video HCR-HC3 Handycam Cam- males and females, recording information on their corder mounted on a Motic SMZ-168 or a Nikon habitat preferences, seasonality, nightly activity levels, Coolpix 5,000 digital camera provided photographic and density each year between 1997 and 2008. In 2006, documentation. when J. Rosen joined the study, we added the new field sites, and in 2007, concentrated in DuPont State Forest RESULTS where P. reticulata had been observed in abundance during 2006: a small enclave opposite the Triple Falls Morphology Trailhead, the forest surrounding the Buck Forest Fender (1966) is the basis for our identification of Parking Area, and Buck Forest Road. Phausis reticulata males. Males range from 5.0–8.5 mm Observations of habitat at each field site included total body length (Table 1) and are approximately 1 mm dominant plant species, amount of vegetative cover, leaf in width. The ratio of length to width of the thorax is litter levels, prominent topographical features and the 2.0:1.5 (Fig. 1A). This measurement includes the three FRICK-RUPPERT AND ROSEN:BLUE GHOST FIREFLY 141

Table 1. Specimen Collections. ‘‘Number’’ refers to the number of specimens in the collection, ‘‘Length’’ is the range of specimen lengths, females indicated by ‘‘F.’’ BC 5 Brevard College Insect Collection, CU 5 Clemson University Collection, NCSU 5 North Carolina State University Insect Collection, UGA 5 University of Georgia Museum of Natural History, FSCA 5 Florida State Collection of , ATBI 5 All Taxa Biodiversity Inventory Database; Great Smoky Mountain National Park Museum.

State County Collection Location Elevation (m) Collection Date Museum Number Length (mm) NC Transylvania Balsam Grove 915 24-May-98 BC 5 5.0–5.5 NC Transylvania Balsam Grove 915 01-Jun-97 BC 2 6 NC Transylvania Balsam Grove 915 01-Jun-98 BC 1 6 NC Transylvania Balsam Grove 915 01-Jun-98 BC 2 (F) 6.0–7.0 NC Transylvania Sherwood Forest 853 06-Jun-06 BC 4 5.0–7.5 NC Transylvania DuPont State Forest 732 01-Jun-06 BC 3 5.0–5.5 NC Transylvania DuPont State Forest 732 01-Jun-06 BC 1 (F) 4.5 NC Avery Grandfather Mtn. unknown 19-Jun-42 NCSU 1 6 NC McDowell Unknown unknown 04-Jul-57 NCSU 1 5.5 NC Mecklenburg Davidson 259 25-May-58 NCSU 8 6.5–8.0 NC Mecklenburg Davidson 259 28-May-58 NCSU 15 7.0–8.5 NC Mecklenburg Mint Hill 239 2-7-Jun-93 NCSU 1 7.5 NC Cabarrus Unknown unknown 02-Jun-58 NCSU 11 6.0–8.0 NC Davidson Unknown unknown 21-Jun-58 NCSU 3 6.0–8.0 NC Davidson Unknown unknown 24-Jun-58 NCSU 2 6.0–6.5 NC Caldwell Unknown unknown 29-May-98 NCSU 1 6 NC Union Monroe 183 29-May-54 NCSU 1 6 NC Burke Unknown unknown 01-May-65 NCSU 11 5.0–6.0 NC Swain Smokemont 610 30-Jun-34 NCSU 1 7.5 NC Swain Beech Gap Trail 915 13-Jun-05 ATBI 13 no data NC Swain Beech Gap Trail 915 13-Jun-05 ATBI 1(F) no data NC Swain Indian Creek 548 23-Jun-05 ATBI 4 no data NC Swain Andrews Bald 1,768 26-Jun-05 ATBI 6 no data SC Oconee Unknown unknown 23-Jun-56 CU 8 no data SC Pickens Clemson 228 01-Jun-59 CU 1 no data SC Pickens Rocky Bottom 533 06-May-87 CU 3 no data SC Greenville Cleveland 305 01-May-91 CU 1(F) no data SC Greenville Cleveland 305 01-May-91 CU 2 no data TN Sevier Porters Creek Trail 579 15-Jun-05 ATBI 7 no data TN Sevier Porters Creek Trail 579 15-Jun-05 ATBI 9 no data TN Sevier Sugarlands Trail 762 16-Jun-05 ATBI 7 no data TN Sevier Chimneys Picnic Area 975 21-Jun-05 ATBI 10 no data TN Sevier Chimneys Picnic Area 975 21-Jun-05 ATBI 1(F) no data TN Sevier Lindsey Creek unknown 23-Jun-05 ATBI 3 no data TN Sevier Lindsey Creek unknown 29-Jun-05 ATBI 3 no data TN Sevier Greenbrier Ranger Stn 458 02-Jul-05 ATBI 5 no data TN Blount Forge Creek&Parsons Branch 588 22-Jun-05 ATBI 7 no data GA Clarke 13 km E of Athens 228 07-May-69 UGA 5 5.0–5.5 GA Clarke Athens/Camp Wilkins 228 30-Apr-41 UGA 2 5 GA Clarke Athens/Camp Wilkins 228 30-Apr-42 UGA 2 5.5 GA Madison 13 km NE of Danielsville 222 05-May-05 UGA 18 7.0–8.0 GA Madison 13 km NE of Danielsville 222 3-6-May-05 UGA 24 5.0–8.0 GA Madison 13 km NE of Danielsville 222 08-May-06 UGA 14 6.0–8.0 FL Dixie Old Town 8 05-Apr-74 FSCA 1 no data segments of the thorax from which the legs, wings, elytra The enormous eyes occupy most of the male head and pronotum arise, but not the ancillary structures. (Figs. 1A, 1C). Each consists of around 1,000 omma- The elytra and pronotum are black in living specimens; tidia. Two long, scythe-shaped mandibles are held the thorax and legs are brown. The entire body is brown crossed over one another (Fig. 1C). A pair of large in preserved specimens, both dry and in 70% ethanol. maxillary palps and a pair of smaller labial palps Abdominal ventral sternites five and six have a white to constitute the remaining mouthparts. Antennae are light-yellow luminiferous area that occupies nearly the composed of 11 antennomeres, with the 2nd antenno- entire segment. The lantern organs are roughly triangu- mere very short; about 1/3 the length of the third. The lar in living specimens (Fig. 1A), but more diffuse within 11th antennomere bears a small, round, distal append- the segments of preserved specimens. The exoskeleton is age. Antennomeres, but not the distal appendage, are reticulate (Fig. 1B), more finely anteriorly and more densely setose. The pronotum (Fig. 1D) has two large, coarsely posteriorly, and also setose. transparent areas over the eyes; these clear zones are 142 JOURNAL OF THE NORTH CAROLINA ACADEMY OF SCIENCE 124(4)

FIG.1. (A, B) Photographs of live, chilled male Phausis reticulata; scale bar 1 mm. (A) Ventral view. Note large eyes and luminferous organs on sternites five and six. Thorax length:width ratio is 2.0:1.5. (B) Dorsal view. Note reticulated elytra and clear areas in pronotum. Gap between elytra is an artifact. (C, D) Drawings of preserved male; scale bar 0.1 mm. (C) In ventral view, the large eyes (ey) occupy most of the head. Anterior to the labial (lp) and maxillary (mp) palps are the crossed, scythe-shaped mandibles (mn). Antennae are composed of 11 antennomeres with the 2nd antennomere much shorter than the 3rd and a distal, round appendage on the 11th. (D) Dorsal pronotum with transparent areas over eyes and concavity that proceeds rearward. concave and the concavity continues rearward but be observed for the position of their light organs. Most transparency does not. The central region and edges of commonly, two pairs of ventral lights, one on the the pronotum are convex. anterior abdomen and one posteriorly, can be observed. Females are larviform. They lack elytra and wings. The female’s head is extensible and often extends Dorsally (Fig. 2A), they bear 11 overlapping plates and forward from beneath the pronotum in live specimens the pronotum bears a conspicuous notch at its apex. The (Fig. 2A). Antennae of females (Fig. 2B) are composed exoskeleton is transparent, and the female appears white of only six setose antennomeres rather than the 11 of the to slightly yellow, primarily because developing eggs are male. Like the male, the last antennomere of the female visible through the transparent body. The 11 dorsal bears a small, round, distal appendage that lacks setae. tergites match the three thoracic and seven abdominal The first and last antennomeres are larger than the sternites except for the last one; this tergite covers the intervening antennomeres. Mandibles, maxillary palps reproductive organs. Light organs of the female cannot and labial palps are identical to those of the male. Eyes be observed in preserved specimens or in living, but of the female are much smaller than those of the male, unilluminated, females. Only living, glowing females can composed of approximately 40 ommatidia each.

FIG. 2. Female Phausis reticulata. (A) Photograph of live female, dorsal view; scale bar 1 mm. The transparent exoskeleton is composed of eleven dorsal plates. The head protrudes forward. (B) Drawing of preserved female head; scale bar 0.1 mm. The antennae (an) have only six antennomeres plus a distal appendage. The eyes (ey) are smaller than the males’, but the labial palps (lp), maxillary palps (mp) and mandibles (mn) are identical. FRICK-RUPPERT AND ROSEN:BLUE GHOST FIREFLY 143

Habitat other areas have very few or none at all. Males prefer All sites are highly diverse southern Appalachian areas with a closed canopy, deep leaf litter and moist soil deciduous forests. The Balsam Grove site is a rich conditions. Coves with streams or seepages are preferred amphibolite cove, with indicator trees including White over drier sites. Males rarely fly from the forest proper Basswood (Tilia americana var. heterophylla), Silverbell into grassy meadows or open roadsides where the larger (Halesia tetraptera), White Ash (Fraxinus americana), flashing species of fireflies are common. Sweet Birch (Betula lenta), and herbs such as Ginseng Activity is highest when moisture levels are high from (Panax quinquefolius), Bloodroot (Sanguinaria canaden- recent gentle precipitation. Males fly during light drizzle, sis) and many others. The DuPont site has more acidic but not during heavy rainfall. Heavy rain events such as soils, with an abundant shrub layer of Rhododendron severe thunderstorms or several days of very heavy maximum. All sites are in close proximity to a small rainfall reduce activity levels and often decrease stream or seepage area and the forest floor is covered subsequent activity during the reminder of the season. with a thick layer of moist, spongy leaf litter. Annual Very dry conditions during the season also reduce rainfall at all sites is abundant, reaching an average of activity levels. Activity is also higher with darker 220 cm in Transylvania County. conditions. A new moon or early waxing phase as well as cloud cover provides darkest conditions early in the evening when these fireflies are active. Seasonality and Nightly Activity Males first appeared in mid-May, peaked around 1 Male Luminescence and Behavior June, and disappeared by mid-June at the Balsam Grove site between 1997 and 2008. In 2006 and 2007 at the Light produced by P. reticulata males is emitted from DuPont State Forest site, males appeared on or about the fifth and sixth sternites, and light emission is 20 May, peaked on 1 June, and disappeared by 10 June. characterized by a constant glow, although the intensity Ground temperature was 17uC and air temperature of the light may vary over time and between individuals. was 19uC on 2 June 2008 at the Balsam Grove site at the This light appears to be a bluish-white from a distance, time of emergence (2,130). Ground temperature varied but bright green when examined at close range. only slightly throughout the next 24 hr, dropping to While males do not ‘‘flash’’ in the species-specific 16uC at 0700 and returning to 17uC by 1,700. Ground patterns seen in other genera, they are able to turn their temperature was also 17uC on 31 May 2006 in DuPont lights completely off and then back on again. There is no State Forest at the time of emergence; air temperature regular pattern or timing involved in the off/on was 19.5uC. Soil temperature remained steady at 17uC behavior. Males may illuminate none, one, or both of for the next three days of observation. their luminiferous segments. Sun sets at 2,040 in early June in western North There is considerable variation in the intensity of light Carolina. Males begin to emerge about 40 min after emitted by steadily glowing males, and males can change sunset (2,120), but rapidly increase in number as the this intensity abruptly. Frequently, the intensity is so forest darkens. Peak activity occurs about 80 min after bright that males illuminate a circular patch of light on sunset (2,200). Activity begins to decline at about the ground beneath them, or cast shadows if vegetation 125 min after sunset (2,245). Activity levels are very low interrupts the illumination between the male’s light by 170 min after sunset (2,330) and nearly non-existent organ and the ground. This ‘‘spotlight phenomenon’’ after midnight. For example, in 2006 in DuPont State may be related to the search for a female, although we Forest, 40 min after sunset, 15 males were present in never observed such an outcome; the several times we 0.1 hectares. Fifty males were present in this same area by observed this behavior, the males merely slowed down, the time of peak activity. The entire site occupied four illuminated an area, and then flew away. hectares and contained approximately 2000 males during An apparent flickering in the male’s luminescence is the peak period in 2006. Females were observed only near likely to be an illusion. Vegetation often intermittently the time of peak in male activity, at around 2,200. blocks the line of sight between the observer and the Density of males is variable between years and firefly. In addition, sometimes the light segments are locations. In Balsam Grove, 2–3 males per square meter oriented toward the observer, while at other times they are common and occasionally densities reach 4–5/m2.In are pointed away. DuPont State Forest, the average density of males in When males first emerge, they fly only a few 2006 and 2008 was about one per square meter, and in centimeters off the ground. They slowly ascend from 2007, about 0.5 per square meter. Density of males was the leaf litter, eventually reaching heights of about one lower than one per square meter at all other sites. meter above ground. The presence of a hill or slope can Distribution of the males is patchy at all sites; certain create the illusion that a male is flying several meters in areas of the forest contain large numbers of males, while the air. Most remain at a constant height of about one 144 JOURNAL OF THE NORTH CAROLINA ACADEMY OF SCIENCE 124(4) meter and fly rather slowly, at about 10 cm/s. Nearly all light organs appeared to change. These pairs of lights in males observed maintained a fairly steady speed, but an expanded female merged into a single anterior and could rapidly increase their rate of speed, especially posterior light further apart from each other. Females evident when we attempted to capture them. Individual moved by alternately expanding and contracting the males could rapidly ascend or descend, perhaps in abdomen to inch along the substrate. response to a perceived predator. When approached, they often respond by turning off their lights; otherwise, Mating Behavior we could discern no difference in their overall behavior during evenings of ‘‘firefly tours,’’ when 25–30 people Experiments performed with two females (2006 walked slowly through the DuPont State Forest site. DuPont State Forest) that were restrained in transpar- Mating, both experimentally induced and under natural ent containers resulted in abnormal behavior. Neither conditions, was observed on evenings when a large female reacted by turning on her lights even when group of people was present. glowing males flew directly overhead. Adding males to the containers caused no change; neither males nor The flight pattern of the males is erratic and each females activated their lights. When one of these females moves independently of the others. They produce no was subsequently released directly into the leaf litter and audible noise. The constant glow, erratic but slow a male was placed next to her, mating occurred. During motion, and absolute silence of the phenomenon mating, the male grasped the female with his legs and intrigue many people and account for the growing curled his abdomen under hers. Both had their lights off popularity of ‘‘firefly tours’’ in DuPont State Forest, during mating. Great Smoky Mountains National Park, and other locations. A female was collected in 2008 in DuPont State Forest by observing a stationary, glowing male. The male mounted and attempted to mate with her, but was Female Behavior and Luminescence unsuccessful. She kept the tip of her abdomen pressed Nine females were observed and collected during the into the leaf litter. After several attempts, the male 2006–2008 field seasons although thousands of males stopped glowing and walked away. Upon collecting the were observed. Seven females were tucked into the leaf female and adding her to a container with several males, litter (DuPont State Forest; Asbury Hills), and two were mating occurred. This female was never illuminated, nor exposed on top of the leaf litter (Pisgah National Forest; were any of the restrained males, one of whom Tremont). All females were found in areas shaded by eventually mated with her. They remained coupled for trees and/or woody shrubs, with thick, moist leaf litter. approximately 20 min. This female presumably exhibit- A similar number of females (fewer than 10 each season) ed mate selection, rejecting the first, glowing male and were observed at the Balsam Grove site. accepting the second, non-glowing one. It is possible, Two females from Pisgah and Tremont were found on however, that the artificial container altered her slopes, and they sat parallel to the slope, with the dorsal behavior toward the second male. side angled outward. Their lights remained shining with A second female was observed in 2008 in Balsam a constant intensity that was of the same brightness as Grove that also rejected the first two males that arrived. an average male. In contrast, females from DuPont The males crawled over and around the female, but she State Forest and Asbury Hills, like those in Balsam did not allow them to mate. One non-glowing male was Grove, were found tucked down in a depression of the already present when the illuminated female was first leaf litter. These females shone with a steady light that observed. While under observation, three more illumi- was dimmer than the females seen on slopes; they were nated males approached from directly downwind. Each also dimmer than most males, making them difficult to cut off his light and dropped to the ground as he neared locate. her. When the first of these males arrived, he displaced The female luminescent organs consist of a pair in the the male already present, but was unable to mate. The anterior abdomen and another pair in the posterior other two males did not locate the still-illuminated abdomen. They are not homologous to the position of female on the ground. the unpaired male organs in the fifth and sixth sternites. Mating under natural conditions was observed in The female’s glow could be observed either dorsally or 2007 at DuPont State Forest and in Balsam Grove, ventrally; presumably the luminescent organs are where a steadily glowing female was found tucked into a located ventrally as in the male, but shine through her small depression in the leaf litter. Several males flew transparent exoskeleton. We have observed two females over her without stopping, but one male approached the (in Balsam Grove in 1998 and 2008) that had an extra female, flew past her, and then reversed his direction of pair of light organs posteriorly. As the females expanded flight. In Balsam Grove, this male then cut off his light, and contracted their abdomens, the configuration of the dropped to the ground, walked a short distance to the FRICK-RUPPERT AND ROSEN:BLUE GHOST FIREFLY 145 female, and mated with her. In DuPont, a different highest density of males occurs among trees and scenario occurred. A second male approached from the underbrush in close proximity to bodies of water. Both opposite direction, and both males flew down close to studies found females in moist leaf litter in shady areas the female and hovered over her. The second male underneath vegetation. The abundant moisture, large stopped emitting light and dropped rapidly to the annual rainfall, thick blankets of leaf litter and heavy ground. The female’s glow continued until her light shade found in southern Appalachian forests provides was slowly eclipsed as the male mounted her. Over the P. reticulata with ideal habitat. Much of the land in course of about two min, the female’s light slowly grew western NC, eastern TN, and extreme western SC dimmer and then became totally dark. The fireflies were remains minimally disturbed, forested, public land. The then observed for the next 10 min, but neither resumed long-term stability of these forests undoubtedly contrib- glowing. utes to the species’ presence. Since the soft-bodied female is probably prone to Response to Stimuli desiccation, we agree with Lloyd (1965) that females are likely confined to moist, sheltered areas and the males It is not clear whether males time their activity by the mostly confine their flight to these heavily vegetated change in light levels or by a set circadian rhythm. During areas to maximize the chance of locating a female. Since the day, males kept in the dark (in transparent containers P. reticulata is so moisture-dependent, it is likely not with moist toweling) were inactive; they did not respond very drought-tolerant, which may account for the to stimuli including light or a gentle shaking. A circadian somewhat lower numbers of males observed in 2007, a rhythm is indicated because they did not alter their year of dry spring and summer conditions in much of activity levels when the light/dark cycle was reversed. the southeast. Around 1,800, when they were moved from the dark to a Many other species of fireflies appear to be declining bright location, two of the four males started moving in numbers from habitat loss and pollution (Lloyd slowly around the jar. One emitted light from one of his 2004), and P. reticulata may be especially vulnerable to two segments, and the other emitted light from both habitat loss. Because adult females of P. reticulata are segments. Within just a few minutes, however, both not flighted or otherwise very mobile, eggs are probably turned off their lights and became inactive again. All laid close to the area from which the female hatches. males were active and illuminated their light segments Larvae likely stay in this same general vicinity, and the when their containers were moved outdoors at 2,120. pupal stage is almost certainly immobile. The adult Shining a bright, white beam of light on a firefly male, while winged, is not a strong flyer and probably elicited different responses. Some males (2006 DuPont does not range very far from the area in which he State Forest) altered their flight course and turned away eclosed. This relative immobility, along with the habitat from the light, others (2006 Greenbrier) did not react at requirement described above, makes the species vulner- all, but most reacted by shutting off their lights for able to population decline from habitat loss. Not only several minutes. Females did not react to the white light. are the females slow to colonize new or disturbed They continued to glow whether the light was off or on, locations, but separated populations are unlikely to which aided in our ability to capture them. When a red cross-breed. light or blue light was used, neither males nor females We expected P. reticulata to occur in Rabun County, reacted to it. We altered our collection techniques to use GA. Not only does LeConte (1851; 1881) report them only red light because it did not alter the behavior of any from Georgia, but Warwoman Dell, the specific location of the males (or females) and it did not affect the we examined in Rabun County, has a habitat similar to collector’s dark-adapted eyesight. that of our other collection locations. It has a well- While males and females were restrained in contain- developed, diverse forest with abundant leaf litter, ers, their response to physical disturbance was noted by moisture provided by a small stream, and its elevation gently tapping on the side of the jar. Two of four males is 640 meters. Although we did not collect them on 13 responded by dimming and brightening their lights, and June 2006, their display may have already been over, for a female illuminated her lights immediately when the jar this is late in the season for NC sites. Further was tapped. Since one function of bioluminescence in examination is warranted. fireflies is to advertise their unpalatability (Eisner et al. The short adult season may be related to ground 2005), the increase in brightness may be a warning. temperature, which would be expected to vary between elevations. Pupation from larval to adult form in other fireflies lasts one to three weeks and is temperature DISCUSSION dependent (Lloyd 2004). Our observations of 17uCat Our observations of P. reticulata’s habitat are the time of peak density both in 2006 at DuPont State consistent with those described by Lloyd (1965). The Forest and in 2008 at Balsam Grove suggest that the 146 JOURNAL OF THE NORTH CAROLINA ACADEMY OF SCIENCE 124(4) threshold for P. reticulata emergence is slightly lower, result from differences in our perception of color that is perhaps 16uC. In Transylvania County, NC at sites affected by low light levels. Future measurements of the around 900 meters, males first appear in mid-May, peak wavelength of the male’s illumination are in order, even at 1 June, and decline through mid-June. In nearby though other glowworm fireflies do not restrict their Cleveland, SC at 307 meters, seasonality is markedly responses to a particular wavelength (Branham 2003). different. Males first emerge in mid-April, peak in early We interpret visual communication between the sexes May, and decline through mid-May (Lewis, pers. in P. reticulata to be of a very simple form. A male comm.). identified a glowing female, hovered briefly, then It is probable that the date of emergence is now earlier dropped to the ground and walked to the female, which than in previous years. Lewis (pers. comm.) reports that is very similar to Lloyd’s (1965) observations. However, in the late 1970’s, the season began around 5 May, in contrast to Lloyd’s 1965 study, we observed females which is two to three weeks later than now. Lloyd (1965) glowing in the absence of males and never observed a reports that peak activity occurs from mid-June to mid- non-luminescent female to illuminate in response to a July near Gatlinburg, TN and at the base of Mt. Pisgah, male passing overhead. The morphological differences NC. P. reticulata males were present but few in number in eye structures between the sexes (around 1000 versus at the Mt. Pisgah site on 8 June 2008, suggesting that the 40 ommatidia per eye) would seem to suggest that the peak period was past, as it was at other sites. Although male locates the female by her glow, but that the female the elevations at the actual collections sites are not is unlikely to respond to illuminated males that are reported, we estimate 440 meters for Gatlinburg and distant. Females advertise themselves by glowing, and 1,220 meters for the parking area at the base of Mt. sooner or later they are located by a male, but there does Pisgah. The earliest seasonal collection record we have not seem to be an interactive communication using found is 5 April 1974 from Dixie County, FL, estimated bioluminescence between the two. In other species of at 8 meters. The latest collection record was 4 July 1957 Phausis, only the females glow, and they attract the non- from McDowell County, NC at unknown specific glowing males (Lloyd 2004). Why P. reticulata males location and elevation (Table 1). glow is unexplained, unless their glow allows them to The size range for specimens seems rather broad, in interact with other glowing males or perhaps with the that males range from 5.0–8.5 mm in length (Table 1; females once they are in close proximity. also Fender 1966). However, we have carefully com- A pheromone may be important in mate identifica- pared a 5.0 mm and 7.5 mm specimen collected on the tion. The single 2008 observation of three males flying same date and location, and can discern no morpho- directly upwind in a straight line toward a female logical differences. Fender (1966) also states that large suggests that they are responding to a pheromone. specimens of P. reticulata have been misidentified as P. Lloyd (2004) suggests that the glowworm fireflies splendidula. Furthermore, the short duration of the (Pleotomus, Pleotomodes, Microphotus, Phausis) may adult display provides a short window for mating, use pheromones as do the daytime-dark fireflies suggesting that these variations in size may be within the (Lucidota atra, Pyropyga nigricans, indictus). norm for the species. Reports of Blue Ghosts as late as In addition, the 2008 observations of females rejecting a July (David Brown and Lynn Faust, pers. comm.) might male may indicate that she exercises mate selection once indicate a sibling species. the male is nearby. Say’s (1825) original description states unequivocally The apparent skewed sex ratio of hundreds of males that ‘‘the thorax is wider than long,’’ but evidence from for every female is probably observer bias. Females, numerous specimens demonstrates that the thorax is hidden in leaf litter, are not as easily observed as the longer than wide. LeConte (1851; 1881), Lloyd (1965) flying males. Lloyd (1983) reports that a similar and Fender (1966) do not comment on the ratio of operational sex ratio exists for Photinus collustrans, length to width in the thorax nor is there a figure of the whose females emerge from their burrows, attract a entire male anatomy. As we note, measurements of the male, mate, and return back underground in an average thorax include the segments but not the ancillary of six min while the males of the species require seven structures that arise from those segments, and there entire evenings to locate a mate. might be confusion over the specific region measured. Like other fireflies (Lloyd 2004), P. reticulata may be Males have the ability to separately control each light negatively affected by the photic noise created by light segment and to vary their intensity of glow. Previous pollution, making it more difficult for males to locate studies do not mention separate control of the two light females. P. reticulata may be especially vulnerable to segments, nor do they describe variation in light negative effects from light pollution because it requires a intensity. darker habitat area than fireflies that fly in the treetops Difference in the apparent color of the male’s glow or in open clearings and the lights of both males and (bluish-white at a distance but greenish up close) may females are rather dim and thus easily overwhelmed. FRICK-RUPPERT AND ROSEN:BLUE GHOST FIREFLY 147

Acknowledgments: The research was supported by EISNER, T., M. EISNER, AND M. SIEGLER. 2005. Pp. 189–193 in grants from the Friends of DuPont Forest and the Beta Secret weapons: defenses of , spiders, scorpions, and other many-legged creatures. Harvard University Press, Cam- Beta Beta Research Foundation. Dr. Edward Ruppert bridge. assisted in field work, photography, and drawings. We FENDER, K. M. 1966. The genus Phausis in America north of are also grateful for the information provided by Dr. Mexico. (Coleoptera-Lampyridae). Northwest Sci. 40:83–95. James Lloyd, Mr. Don Lewis, Ms. Lynn Faust, Dr. LECONTE, J. L. 1851. Synopsis of the Lampyrides of temperate Jonathan Copeland, Dr. Adriean Mayor, and Dr. North America. Proc. Acad. Nat. Sci. Phila. 2:331–347. LECONTE, J. L. 1881. Synopsis of the Lampyridae of the United Christopher Carlton. Mr. Ian Stocks (Clemson Univer- States. Trans. Amer. Entomol. Soc. 9:15–72. sity Arthropod Collection), Dr. Cecil Smith (University LLOYD, J. E. 1965. Observations on the biology of three luminescent of Georgia Museum of Natural History), Mr. Bob Blinn (Coleoptera: Lampyridae, Elateridae). Ann. Entomol. (North Carolina State University Insect Collection), Mr. Soc. Amer. 58(4):588–591. Eric Day (Virginia Tech Insect ID Lab), Dr. Richard LLOYD, J. E. 1966. Studies on the flash communication system in Photinus fireflies. Misc. Publ. No. 130, Mus. Zool., Univ. Hoffman (Virginia Natural History Museum), Dr. Paris Michigan, Ann Arbor. 95 pp. Lambdin (University of Tennessee-Knoxville), and Dr. LLOYD, J. E. 1971. Bioluminescence and communication in insects. Michael Thomas (Florida State Collection of Arthro- Ann. Rev. Entomol. 16:97–122. pods) coordinated specimen loans and museum visits. LLOYD, J. E. 1983. Bioluminescence and communication in insects. One anonymous reviewer and editor Dr. Frank Ann. Rev. Entomol. 28:131–160. LLOYD, J. E. 2003. On research and entomological education VI: Schwartz provided helpful critiques of the manuscript. firefly species and lists, old and new. Florida Entomol 86(2):99–113. LLOYD, J. E. 2004. Fireflies (Coleoptera: Lampyridae). Pp. 840–862 LITERATURE CITED in J. L. Capinera (ed.), Encyclopedia Entomol., Vol. 2. Kluwer BRANHAM, M. A. 2003. A new technique for collecting glowworm Acad. Publ., Boston, MA. fireflies (Coleoptera: Lampyridae). Coleopterists Bull. 57:114– MCDERMOTT, F. A. 1948. The fireflies of Delaware, with general 115. notes on fireflies. Soc. Nat. Hist. Delaware, Wilmington. 36 pp. SAY, T. 1825. Descriptions of new species of Coleopterous Insects BRANHAM, M. A., AND J. W. WENZEL. 2003. The origin of photic behavior and the evolution of sexual communication in fireflies inhabiting the United States. J. Acad. Nat. Sci. Phila. 5:160–204. (Coleoptera: Lampyridae). Cladistics 19:1–22. Received 7 August 2008