Editing Firefly (section)

=== Light and chemical production ===
{{further|Bioluminescence}}

[[File:Firefly composite.jpg|thumb|left|''[[Photuris]]'' female by flash photography (above); by her own light (below)]]

Light production in fireflies is due to the chemical process of [[bioluminescence]]. This occurs in specialized light-emitting [[organ (biology)|organ]]s, usually on a female firefly's lower [[Abdomen (insect anatomy)|abdomen]]. The enzyme [[luciferase]] acts on [[Firefly luciferin|luciferin]], in the presence of [[magnesium]] ions, [[Adenosine triphosphate|ATP]], and oxygen to produce light. Oxygen is supplied via an abdominal trachea or breathing tube. [[Gene]] coding for these substances has been [[Luciferase#Applications|inserted into many different organisms]].<ref name="Day 2009">{{cite book |last=Day |first=John |chapter=Beetle bioluminescence: a genetic and enzymatic research review |year=2009 |publisher=Research Signpost: Kerala |editor=Meyer-Rochow, V. B. |title=Bioluminescence in Focus |pages=325–355 }}</ref> Firefly luciferase is used in [[forensics]], and the enzyme has medical uses – in particular, for detecting the presence of [[Adenosine triphosphate|ATP]] or magnesium.<ref name="Lewis Cratsley 2008"/> Fireflies produce a "cold light", with no [[infrared]] or [[ultraviolet]] frequencies. The light may be yellow, green, or pale red, with [[wavelength]]s from 510 to 670 nanometers. Some species such as the dimly glowing "[[Phausis reticulata|blue ghost]]" of the Eastern US may seem to emit blueish-white light from a distance and in low light conditions, but their glow is bright green when observed up close.<ref name="Frick-Ruppert_Rosen_2008">{{Cite journal |last1=Frick-Ruppert |first1=Jennifer E. |last2=Rosen |first2=Joshua J. |date=2008 |title=Morphology and Behavior of Phausis Reticulata (Blue Ghost Firefly) |journal=Journal of the North Carolina Academy of Science |volume=124 |issue=4 |pages=139–147}}</ref> Their perceived blue tint may be due to the [[Purkinje effect]].<ref>{{cite journal |last1=Branchini |first1=Bruce R. |last2=Southworth |first2=Tara L. |last3=Salituro |first3=Leah J. |last4=Fontaine |first4=Danielle M. |last5=Oba |first5=Yuichi |title=Cloning of the Blue Ghost (Phausis reticulata) Luciferase Reveals a Glowing Source of Green Light |journal=[[Photochemistry and Photobiology]] |date=2017 |volume=93 |issue=2 |pages=473–478 |pmid=27696431 |doi=10.1111/php.12649 |doi-access=free }}</ref> During a study on the genome of ''Aquatica leii'', scientists discovered two key genes are responsible for the formation, activation, and positioning of this firefly's light organ: Alabd-B and AlUnc-4.<ref>{{Cite journal |last1=Fu |first1=Xinhua |last2=Zhu |first2=Xinlei |date=2024-03-05 |title=Key homeobox transcription factors regulate the development of the firefly's adult light organ and bioluminescence |journal=Nature Communications |language=en |volume=15 |issue=1 |pages=1736 |doi=10.1038/s41467-024-45559-7 |pmid=38443352 |issn=2041-1723|pmc=10914744 |bibcode=2024NatCo..15.1736F }}</ref>

Adults emit light primarily for mate selection. Early larval bioluminescence was adopted in the phylogeny of adult fireflies, and was repeatedly gained and lost before becoming fixed and retained as a mechanism of sexual communication in many species.<ref name="Lewis Cratsley 2008"/><ref>{{cite journal |last1=Martin |first1=Gavin J. |last2=Branham |first2=Marc A. |last3=Whiting |first3=Michael F. |last4=Bybee |first4=Seth M. |date=February 2017 |title=Total evidence phylogeny and the evolution of adult bioluminescence in fireflies (Coleoptera: Lampyridae) |journal=[[Molecular Phylogenetics and Evolution]] |volume=107 |pages=564–575 |doi=10.1016/j.ympev.2016.12.017 |pmid=27998815 |doi-access=free|bibcode=2017MolPE.107..564M }}</ref> Adult lampyrids have a variety of ways to communicate with mates in courtships: steady glows, flashing, and the use of chemical signals unrelated to photic systems.<ref>{{cite journal |last1=Stanger-Hall |first1=K. F. |last2=Lloyd |first2=J. E. |last3=Hillis |first3=D. M. |title=Phylogeny of North American fireflies (Coleoptera: Lampyridae): implications for the evolution of light signals |journal=[[Molecular Phylogenetics and Evolution]] |volume=45 |issue=1 |pages=33–49 |doi=10.1016/j.ympev.2007.05.013 |year=2007 |pmid=17644427|bibcode=2007MolPE..45...33S }}</ref> Chemical signals, or pheromones, are the ancestral form of sexual communication; this pre-dates the evolution of flash signaling in the lineage, and is retained today in diurnally-active species.<ref name="Lewis Cratsley 2008" /><ref>{{cite journal |last=Branham |first=M. |date=February 2003 |title=The origin of photic behavior and the evolution of sexual communication in fireflies (Coleoptera: Lampyridae) |journal=[[Cladistics (journal)|Cladistics]] |volume=19 |issue=1 |pages=1–22 |doi=10.1111/j.1096-0031.2003.tb00404.x |pmid=34905865 |s2cid=46266960 }}</ref> Some species, especially lightning bugs of the [[genera]] ''[[Photinus (beetle)|Photinus]]'', ''[[Photuris (genus)|Photuris]]'', and ''[[Pyractomena]]'', are distinguished by the unique courtship flash patterns emitted by flying males in search of females. In general, females of the genus ''Photinus'' do not fly, but do give a flash response to males of their own species. Signals, whether photic or chemical, allow fireflies to identify mates of their own species. Flash signaling characteristics include differences in duration, timing, color, number and rate of repetitions, height of flight, and direction of flight (e.g. climbing or diving) and vary interspecifically and geographically.<ref name=":2">{{Cite journal |last1=Stanger-Hall |first1=Kathrin F. |last2=Lloyd |first2=James E. |date=March 2015 |title=Flash signal evolution in Photinus fireflies: Character displacement and signal exploitation in a visual communication system |journal=[[Evolution (journal)|Evolution]] |volume=69 |issue=3 |pages=666–682 |doi=10.1111/evo.12606 |pmid=25627920 |s2cid=26075485 |doi-access=free }}</ref>{{sfn|Gullan|Cranston|2014|pp=121–122}} When flash signals are not sufficiently distinguished between species in a population, [[sexual selection]] encourages divergence of signaling patterns.<ref name=":2"/>

Synchronization of flashing occurs in several species; it is explained as [[phase synchronization]] and spontaneous order.<ref>{{cite book |last=Murray |first=James D. |url=https://books.google.com/books?id=1QM3h80gb_IC |title=Mathematical Biology |publisher=[[Springer Science+Business Media|Springer]] |year=2002 |isbn=978-0-387-95223-9 |edition=3rd |volume=I. An Introduction |pages=295–299 |language=en |author-link=James D. Murray}}</ref> Tropical fireflies routinely synchronise their flashes among large groups, particularly in Southeast Asia. At night along river banks in the Malaysian jungles, fireflies synchronize their light emissions precisely. Current hypotheses about the causes of this behavior involve diet, social interaction, and altitude. In the Philippines, thousands of fireflies can be seen all year-round in the town of [[Donsol]]. In the United States, one of the most famous sightings of fireflies blinking in [[unison]] occurs annually near [[Elkmont, Tennessee]], in the [[Great Smoky Mountains]] during the first weeks of June.<ref>[http://www.nps.gov/grsm/naturescience/fireflies.htm Synchronous Fireflies – Great Smoky Mountains National Park]. Nps.gov (3 June 2013). Retrieved on 22 June 2013.</ref> [[Congaree National Park]] in [[South Carolina]] is another host to this phenomenon.<ref>Cross, Robert (23 May 2004) "[https://web.archive.org/web/20050318055636/http://www.seacoastonline.com/2004news/05232004/travel/17745.htm Tree huggin']". ''Chicago Tribune''.</ref>

Female "femme fatale" ''Photuris'' fireflies mimic the photic signaling patterns of the smaller ''Photinus'', attracting males to what appears to be a suitable mate, then eating them.<ref name="Lewis Cratsley 2008"/> This provides the females with a supply of the toxic defensive lucibufagin chemicals.{{sfn|Gullan|Cranston|2014|p=387}}

Many fireflies do not produce light. Usually these species are diurnal, or day-flying, such as those in the genus ''[[Ellychnia]]''. A few diurnal fireflies that inhabit primarily shadowy places, such as beneath tall plants or trees, are luminescent. One such genus is ''[[Lucidota]]''.

Non-bioluminescent fireflies use pheromones to signal mates. Some [[Basal (phylogenetics)|basal]] groups lack bioluminescence and use chemical signaling instead. ''Phosphaenus hemipterus'' has photic organs, yet is a diurnal firefly and displays large antennae and small eyes. These traits suggest that pheromones are used for sexual selection, while photic organs are used for warning signals. In controlled experiments, males coming from downwind arrived at females first, indicating that males travel upwind along a pheromone plume. Males can find females without the use of visual cues, so sexual communication in ''P. hemipterus'' appears to be mediated entirely by pheromones.<ref>{{cite journal |last1=De Cock |first1=R. |last2=Matthysen |first2=E. |title=Sexual communication by pheromones in a firefly, ''Phosphaenus hemipterus'' (Coleoptera: Lampyridae) |doi=10.1016/j.anbehav.2005.01.011 |year=2005 |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |volume=70 |issue=4 |pages=807–818 |s2cid=53180940 }}</ref>

<gallery mode="packed" heights="190px">
File:Leuchtkäfer - Firefly.JPG|''Lamprohiza'' female by her own light 
File:FireFlies short video.webm|A video of fireflies
File:GluehwuermchenImWald.jpg|Fireflies in the woods near [[Nuremberg]], Germany, 30-second exposure 
</gallery>