Animal Diversity Web

Ge­o­graphic Range

The com­mon east­ern fire­fly, or North Amer­i­can fire­fly, ranges through­out the United States east of the Rocky Moun­tains. ("Fire­fly", 2001)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Lar­vae of the com­mon east­ern fire­fly most often in­habit moist places such as on the ground, under bark, and near streams. Adult fire­flies can be found from late spring to early fall in mead­ows, wood­land edges, and near streams. (Milne and Milne, 1980)

• Habitat Regions
• temperate
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest

• Other Habitat Features
• suburban
• agricultural
• riparian

Phys­i­cal De­scrip­tion

The com­mon east­ern fire­fly is, in fact, not a fly, but a type of bee­tle. The av­er­age adult is dark brown and 10-14 mm long. Like all in­sects, it has a hard ex­oskele­ton, six jointed legs, two an­ten­nae, com­pound eyes, and a body di­vided into three parts head, tho­rax, and ab­domen). Its head has a rounded cover out­lined in yel­low and ac­cented with two or­ange spots. Phot­i­nus pyralis also has two pairs of wings. The first pair, the ely­tra, form a cover over the sec­ond pair and is dark brown with nar­row yel­low side mar­gins. Only males use the sec­ond pair for fly­ing; fe­males usu­ally have short wings, and do not fly. The last seg­ment of the ab­domen is the sec­tion that lights up, flash­ing bright yel­low-green.

Com­mon east­ern fire­fly lar­vae are char­ac­ter­ized by six legs, a pair of an­ten­nae, and a flat­tened seg­mented ab­domen. Upon emerg­ing from the egg they are gen­er­ally about 1.6 mm in length. By the end of its lar­val stage it will have grown to about 10.3 mm. Fire­fly lar­vae are often re­ferred to as "glow worms" be­cause, like the adults, they emit a glow of light. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; Ar­nett, 1985; Grz­imek, 1972; Milne and Milne, 1980; Tweit, 1999)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes shaped differently

• Range length

  10 to 14 mm

  0.39 to 0.55 in

De­vel­op­ment

Fire­fly eggs, which also emit a slight glow, hatch after four weeks into flight­less lar­vae, the longest stage of the fire­fly life cycle. Lar­vae live one to two years and can be seen glow­ing on damp ground and near streams. After pass­ing through the lar­val stage, the de­vel­op­ing fire­fly moves into cham­bers in the moist soil and pu­pates. While pu­pat­ing, it un­der­goes meta­mor­pho­sis, emerg­ing from the pupa as an adult. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; "Fire­fly", 2001; Milne and Milne, 1980; Pes­son, 1959)

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

Fire­flies use spe­cific flash­ing sig­nals to find a mate. Fe­males wait on the ground for pass­ing males to flash their sig­nal, and then an­swer with their own spe­cific sig­nal. It is this com­mu­ni­ca­tion that al­lows the male to find a fe­male with whom he mates. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; "Fire­fly", 2001; Milne and Milne, 1980; Pes­son, 1959)

• Mating System
• polygynandrous (promiscuous)

Fire­flies use spe­cific flash­ing sig­nals to find a mate. Fe­males wait on the ground for pass­ing males to flash their sig­nal, and then an­swer with their own spe­cific sig­nal. It is this com­mu­ni­ca­tion that al­lows the male to find a fe­male with whom he mates. This dat­ing game oc­curs in sum­mer and early fall, and the fe­male gen­er­ally lays about 500 eggs on damp soil dur­ing this time of year. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; "Fire­fly", 2001; Milne and Milne, 1980; Pes­son, 1959)

• Key Reproductive Features
• semelparous
• seasonal breeding
• sexual
• fertilization
  • internal
• oviparous

• Average eggs per season

  500

Lifes­pan/Longevity

Adult Phot­i­nus pyralis live 5 to 30 days. (Grz­imek, 1972; Milne and Milne, 1980)

• Typical lifespan
  Status: wild

  5 to 30 days

Be­hav­ior

Fire­fly lar­vae spend win­ter and early spring bur­rowed into the soil. In late spring, they emerge to feed. Adult fire­flies use their glow to both ward off preda­tors and at­tract mates. It was orig­i­nally thought that the light sig­nals of the fire­fly would at­tract preda­tors; how­ever, the com­mon east­ern fire­fly con­tains a steroid that is poi­so­nous, and this de­ters po­ten­tial preda­tors such as birds and frogs.

The light sig­nal ben­e­fits P. pyralis most dur­ing mat­ing. At dusk males take flight while fe­males wait perched on the ground or in bushes. While in flight, the male emits, on av­er­age, a 0.3 sec­ond flash every 5.5 sec­onds. This par­tic­u­lar sig­nalling se­quence is spe­cific to P. pyralis; how­ever, it is the fe­males's re­sponse that en­ables the male com­mon east­ern fire­fly to find a mate of the same species. The fe­male flashes a re­sponse ap­prox­i­mately two sec­onds later, a spe­cific and cru­cial in­ter­val for this fire­fly species. Once the male rec­og­nizes the fe­male P. pyralis, it flies down to the ground where mat­ing takes place. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; "Fire­fly", 2001; Grz­imek, 1972; Tweit, 1999)

• Key Behaviors
• flies
• nocturnal
• motile

Com­mu­ni­ca­tion and Per­cep­tion

• Communication Channels
• visual

• Other Communication Modes
• photic/bioluminescent

• Perception Channels
• visual

Food Habits

Both adult and lar­val Phor­inua pyralis are car­niv­o­rous. They feed on other in­sects (in­clud­ing other fire­flies), earth­worms, and snails. When feed­ing, they in­ject poi­son to im­mo­bi­lize and liq­uefy their prey. This al­lows the fire­flies or lar­vae to suck up their meal. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999)

• Primary Diet
• carnivore
  • insectivore
  • molluscivore
  • vermivore

• Animal Foods
• insects
• mollusks
• terrestrial worms

Pre­da­tion

An in­ter­est­ing preda­tor of Phot­i­nus pyralis is the fe­male Pho­turis pyralis. This fire­fly mim­ics the sig­nal of the fe­male Phot­i­nus pyralis and lures male Phot­i­nus pyralis that are ex­pect­ing to mate. How­ever, when the male com­mon east­ern fire­fly reaches this mim­ic­k­ing species, he quickly be­comes the fe­male preda­tor's meal. (Milne and Milne, 1980)

• Known Predators

  • Photuris pyralis

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

The chem­i­cal uti­lized by the com­mon east­ern fire­fly for bi­o­lu­mi­nes­cence is a com­plex or­ganic com­pound, lu­ciferase. Fire­flies have re­cently been har­vested by the bio­chem­i­cal in­dus­try for this im­por­tant com­pound. Re­searchers dis­cov­ered a tech­nique to splice the gene con­tain­ing lu­ciferase into the DNA of other plants and an­i­mals. They use this in trac­ing the in­her­i­tance of a par­tic­u­lar dis­ease-re­sis­tant gene by splic­ing the bi­o­lu­mi­nes­cence gene into the dis­ease-re­sis­tant gene in a par­ent plant or an­i­mal. The dis­ease-re­sis­tant gene can then be traced in the off­spring, be­cause if it is in­her­ited, it will glow. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; Tweit, 1999)

• Positive Impacts
• source of medicine or drug

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There is no known neg­a­tive eco­nomic im­por­tance for hu­mans.

Con­ser­va­tion Sta­tus

This species does not re­quire any spe­cial sta­tus.

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

Phot­i­nus pyralis is the most com­mon of 1900 species of fire­flies.

The fire­fly pro­duces light in the pres­ence of oxy­gen, mag­ne­sium, and adeno­sine triphos­phate by using an en­zyme, lu­ciferase, to ox­i­dize a com­plex or­ganic com­pound, lu­ciferin. The light pro­duced is often re­ferred to as "cold light" be­cause al­most all the en­ergy is re­leased in the form of light and very lit­tle is wasted as heat. The wave­length range of this light spans from 520-620nm, and its bright­ness reaches 1/40 that of a can­dle. This bright light is what at­tracts most of the com­mon east­ern fire­fly's pop­u­lar­ity. ("Fire­fly or Light­ning Bug: Phot­i­nus pyralis", 1999; "Fire­fly", 2001; Ar­nett, 1985; Grz­imek, 1972; Milne and Milne, 1980)

Con­trib­u­tors

Sara Di­a­mond (ed­i­tor), An­i­mal Di­ver­sity Web.

Jenny McKen­zie (au­thor), South­west­ern Uni­ver­sity, Stephanie Fab­ri­tius (ed­i­tor), South­west­ern Uni­ver­sity.

Ref­er­ences

1999. "Fire­fly or Light­ning Bug: Phot­i­nus pyralis" (On-line). Ac­cessed April 12, 2001 at http://​www.​enchantedlearning.​com/​subjects/​insects/​beetles/​Fireflyprintout.​html.

2001. Fire­fly. Pp. 134 in World Book. Chicago: World Book In­cor­po­rated.

Ar­nett, R. 1985. Amer­i­can In­sects: A Hand­book of the In­sects of North Amer­ica and Mex­ico. New York: Van Nos­trand Rein­hold Com­pany.

Grz­imek, D. 1972. Grz­imek's An­i­mal Life En­cy­clo­pe­dia. New York: Van Nos­trand Rein­hold Com­pany.

Milne, L., M. Milne. 1980. The Au­dobon So­ci­ety Field Guide to North Amer­i­can In­sects and Spi­ders. New York: Chan­ti­cleir Press.

Pes­son, P. 1959. The World of In­sects. New York: Mc­Graw-Hill Book Com­pany.

Tweit, S. 1999. Dance of the Fire­flies. Audubon, 101, Issue 4: 16,28-31.