Firefly Species Research Articles

Luminescent characteristics and mitochondrial COI barcodes of nine cohabitated Taiwanese fireflies.

Over 50 Taiwanese firefly species have been discovered, but scientists lack information regarding most of their genetics, bioluminescent features, and cohabitating phenomena. In this study, we focus on morphological species identification and phylogeny reconstructed by COI barcoding, as well as luminescent characteristics of cohabited Taiwanese firefly species to determine the key factors that influenced how distinct bioluminescent species evolved to coexist and proliferate within the same habitat. In this study, 366 specimens from nine species were collected in northern Taiwan from April to August, 2016-2019. First, the species and sex of the specimens were morphologically and genetically identified. Then, their luminescent spectra and intensities were recorded using a spectrometer and a power meter, respectively. The habitat temperature, relative humidity, and environmental light intensity were also measured. The cytochrome oxidase I (COI) gene sequence was used as a DNA barcode to reveal the phylogenetic relationships of cohabitated species. Nine species-eight adult species (Abscondita chinensis, Abscondita cerata, Aquatica ficta, Luciola curtithorax, Luciola kagiana, Luciola filiformis, Curtos sauteri, and Curtos costipennis) and one larval Pyrocoelia praetexta-were morphologically identified. The nine species could be found in April-August. Six of the eight adult species shared an overlap occurrence period in May. Luminescent spectra analysis revealed that the λ max of studied species ranged from 552-572 nm (yellow-green to orange-yellow). The average luminescent intensity range of these species was about 1.2-14 lux (182.1-2,048 nW/cm2) for males and 0.8-5.8 lux (122.8-850 nW/cm2) for females, and the maximum luminescent intensity of males was 1.01-7.26-fold higher than that of females. Compared with previous studies, this study demonstrates that different λ max, species-specific flash patterns, microhabitat choices, nocturnal activity time, and/or an isolated mating season are key factors that may lead to the species-specific courtship of cohabitated fireflies. Moreover, we estimated that the fireflies start flashing or flying when the environmental light intensity decreased to 6.49-28.1 lux. Thus, based on a rough theoretical calculation, the sensing distance between male and female fireflies might be 1.8-2.7 m apart in the dark. In addition, the mitochondrial COI barcode identified species with high resolution and suggested that most of the studied species have been placed correctly with congeners in previous phylogenies. Several cryptic species were revealed by the COI barcode with 3.27%-12.3% variation. This study renews the idea that fireflies' luminescence color originated from the green color of a Lampyridae ancestor, then red-shifted to yellow-green in Luciolinae, and further changed to orange-yellow color in some derived species.

Photuris lugubris Female Fireflies Hunt Males of the Synchronous Firefly Photinus palaciosi (Coleoptera: Lampyridae).

Simple SummaryAdults of most fireflies do not feed, except for the females of several species of Photuris, which eat males of other firefly species. In most cases, female Photuris attract their prey by responding with glows or flashes to the male’s bioluminescent signals, as if they were potential mates. For this reason, female Photuris are also called femmes fatales. In this paper, we provide evidence that the females of Photuris lugubris are femmes fatales of the males of the firefly Photinus palaciosi. We present different types of field observations suggesting that the females of P. lugubris attract males of P. palaciosi by responding to their bioluminescent signals and that, as a consequence, sometimes these are captured and eaten. We demonstrate experimentally that male P. lugubris are not predators of P. palaciosi. We also present experimental evidence that females of P. lugubris mate with multiple males and discuss the potential implications of this observation for the switch between mating and hunting behaviour. P. palaciosi is a firefly that reaches very high densities of flashing males during the reproductive season and that, intermittently, they synchronize their flashes providing a magnificent show that in the last few years has been the focus of tourist activities. Thus, our study also adds to the knowledge on the natural history of a species of economic interest.Femmes fatales (Ff) are female fireflies that hunt and feed on the males of other firefly species that they attract by responding with glows or flashes to their bioluminescent signals. Here, we present field observations demonstrating that Photuris lugubris females are Ff of male Photinus palaciosi, a synchronous firefly exploited as a tourist attraction in the mountains of central Mexico. We show that the hunting success of the Ff is low, as observed in previous studies, suggesting that the impact of predation on the prey population is low. We present experimental data showing sex-specific hunting behaviour, since only female P. lugubris fed on P. palaciosi. We also present experimental data showing that at least some female P. lugubris mate multiple times; we discuss the implications of this discovery for the switch between the mating and hunting modes of Ff. We discuss open questions, as well as the possible impact of Ff on tourism focused on synchronous fireflies.

Spectral tuning of bioluminescence and visual sensitivity in males of Brazilian firefly species inhabiting dim light environments (Coleoptera: Elateroidea: Lampyridae).

Bioluminescence in fireflies is essential for sexual communication, and each species has evolved a specific bioluminescence emission capable of being detected by its visual system. This spectral "tuning"between visual sensitivity and bioluminescent emission has been established in 14species of North American fireflies inhabiting diverse photoecological niches. Here we extend that research to three Brazilian species. Macrolampis omissa inhabits the Cerrado (savannas), while Photinus sp1 and Pyrogaster moestus are often sympatric species inhabiting borders of mesophyll rain forests and secondary growth. P. moestus particularly favors humid areas of the forest. M. omissa and Photinus sp1 are twilight-active fireflies emitting yellow bioluminescence. P. moestus is a "twi-night" species emitting green bioluminescence. It initiates flashing at the end of twilight and continues activity into the night. The visual spectral sensitivity of dark-adapted compound eyes in these three species is similar, showing a maximum in the yellow-green wavelengths and a secondary peak in the near-UV, suggesting the presence of two receptors. The bioluminescence emission spectrum in each species is tuned to its yellow-green visual sensitivity peak. Green chromatic adaptation experiments on Photinus sp1 and P. moestus suggest the presence of a blue receptor. The presence of near-UV, blue, and long-wavelength receptors in the compound eyes would enable a trichromatic color vision in Brazilian firefly species active in dim illumination.

Comparative morphology and key to Amydetinae genera, with description of three new firefly species (Coleoptera, Lampyridae).

Amydetinae is an exclusively Neotropical subfamily of fireflies, distributed among three genera: Amydetes Illiger, 1807, Magnoculus McDermott, 1964, and Memoan Silveira & Mermudes, 2013. Here, we describe three new species of Amydetinae: two belonging to Amydetes (A.alexi sp. nov. and A.marolae sp. nov.) and one to the previously monotypic Memoan (Me.conani sp. nov.). All three species are known only from the Atlantic Forest in southeastern Brazil. Endoskeletal structures of Memoan and Magnoculus species are described and compared with those of Amydetes for the first time. After studying the type material, Photinusfruhstorferi Pic, 1942 is transferred to Memoan, generating Memoanfruhstorferi comb. nov., and Me.ciceroi Silveira & Mermudes, 2013 syn. nov. is placed as a junior synonym. We also redescribe Magnoculusobscurus Olivier, 1885 and compare it to other species of genus and to other amydetine taxa to identify potential new diagnostic traits for the Amydetinae and its constituting genera. We provide an updated diagnosis for Memoan, illustrations for all four species, and a distribution map for the three new species, as well as a key to adult males of the three amydetine genera, and an updated key to Amydetes species based on males.

The Compilation Records of Fireflies (Coleoptera: Lampyridae) Diversity and Distribution and Display Trees Throughout Malaysia

The populations of fireflies (Coleoptera: Lampyridae) are increasingly being threatened, and it is, thus, a significant problem in Southeast Asia, particularly Malaysia. Fireflies and their habitat must immediately be protected before they go extinct. Simpson’s Diversity Index used in this paper review to measure the diversity of firefly species across Malaysia. The Simpson’s Diversity Index showed that the richness and evenness of firefly species in Malaysia is infinite diversity with D = 0.2255. The authors compiled and reviewed the studies on the firefly species to incorporate available information/data and emphasised their preferred habitat/display trees in response to the issue. Therefore, this paper was also able to track down records of fireflies’ species’ distribution through the previous studies in eight states in West Malaysia (Peninsula), namely Johor, Kelantan, Kuala Lumpur, Pahang, Perak, Negeri Sembilan, Selangor, and Terengganu, as well as two states in East Malaysia (Borneo), namely Sabah and Sarawak. It indicates that firefly species, especially from the general Pteroptyx (Pteroptyx tener species), are widely distributed in Peninsular Malaysia and East Malaysia. Based on the records from the study conducted by previous researchers, it was found that the population of fireflies is declining in some areas in Malaysia, and so are their habitats and host/display trees that have suffered the same decline. Perhaps, this paper will help broaden human beings’ geographical understanding/knowledge and create awareness which eventually leads to conservation actions of firefly species and their host/display trees.

Haplocauda, a New Genus of Fireflies Endemic to the Amazon Rainforest (Coleoptera: Lampyridae).

Simple SummaryThe Amazon Rainforest is still a frontier in the study of insect biodiversity, housing several species yet to be described and studied. Yet, its continuous deforestation urges scientists to study insect diversity there before it is too late. Here, we identified and described new species and a new genus of fireflies from the Amazon Rainforest. These new species are unique among other fireflies due to their unique abdominal morphology, supposed here to involve a clamping mechanism used during mating.Most firefly genera have poorly defined taxonomic boundaries, especially in the Neotropics, where they are more diverse and more difficult to identify. Recent advances that shed light on the diversity of fireflies in South America have focused mainly on Atlantic Rainforest taxa, whereas lampyrids in other biomes remained largely unstudied. We found three new firefly species endemic to the Amazon basin that share unique traits of the male abdomen where sternum VIII and the pygidium are modified and likely work as a copulation clamp. Here we test and confirm the hypothesis that these three species form a monophyletic lineage and propose Haplocauda gen. nov. to accommodate the three new species. Both maximum parsimony and probabilistic (Bayesian and maximum likelihood) phylogenetic analyses confirmed Haplocauda gen. nov. monophyly, and consistently recovered it as the sister group to Scissicauda, fireflies endemic to the Atlantic Rainforest that also feature a copulation clamp on abdominal segment VIII, although with a different configuration. We provide illustrations, diagnostic descriptions, and keys to species based on males and females. The three new species were sampled from different regions, and are likely allopatric, a common pattern among Amazonian taxa.

Species-Specific Flash Patterns Track the Nocturnal Behavior of Sympatric Taiwanese Fireflies.

Simple SummaryNocturnal fireflies are facing various challenges to their survival (e.g., artificial light pollution and extreme climate change). However, there are still no effective diagnostic tools to distinguish firefly species and monitor how their population size and nocturnal behavior change in the wild. Here, we demonstrated that flash interval (FI), a timing character of firefly flash signaling, can be a reliable species-specific luminescent marker for identifying three species (Abscondita cerata, Luciola kagiana, and Luciola curtithorax) in a wild sympatric population and evaluating their nightly behaviors in video-imagery analysis, as well as a traditional field specimen collection. Our studies provide key information and valuable references for future studies of (1) the behaviors of sympatric fireflies in the wild and (2) the development of automatic and rapid digital diagnostic tools for identifying firefly species and quantifying population size, especially for firefly conservation.It is highly challenging to evaluate the species’ content and behavior changes in wild fireflies, especially for a sympatric population. Here, the flash interval (FI) and flash duration (FD) of flying males from three sympatric species (Abscondita cerata, Luciola kagiana, and Luciola curtithorax) were investigated for their potentials in assessing species composition and nocturnal behaviors during the A. cerata mating season. Both FI and FD were quantified from the continuous flashes of adult fireflies (lasting 5–30 s) via spatiotemporal analyses of video recorded along the Genliao hiking trail in Taipei, Taiwan. Compared to FD patterns and flash colors, FI patterns exhibited the highest species specificity, making them a suitable reference for differentiating firefly species. Through the case study of a massive occurrence of A. cerata (21 April 2018), the species contents (~85% of the flying population) and active periods of a sympatric population comprising A. cerata and L. kagiana were successfully evaluated by FI pattern matching, as well as field specimen collections. Our study suggests that FI patterns may be a reliable species-specific luminous marker for monitoring the behavioral changes in a sympatric firefly population in the field, and has implication values for firefly conservation.

Do predators prefer toxic animals? A case of chemical discrimination by an Asian snake that sequesters firefly toxins.

Several Asian natricine snakes of the genus Rhabdophis feed on toads and sequester steroidal cardiac toxins known as bufadienolides (BDs) from them. A recent study revealed that species of the Rhabdophis nuchalis Group ingest lampyrine fireflies to sequester BDs. Although several species of fireflies are distributed in the habitat of the R. nuchalis Group, only lampyrine fireflies, which have BDs, are included in the diet of these snakes. Thus, we hypothesized that the R. nuchalis Group chemically distinguishes fireflies that have BDs from those that do not have BDs. We also predicted that the R. nuchalis Group detects BDs as the chemical cue of toxin source. To test these predictions, we conducted 3 behavioral experiments using Rhabdophis chiwen, which belongs to the R. nuchalis Group. In the first experiment, R. chiwen showed a moderate tongue flicking response to cinobufagin, a compound of BDs. On the other hand, the snake showed a higher response to the chemical stimuli of lampyrine fireflies (BD fireflies) than those of lucioline fireflies (non-BD fireflies). In the second experiment, in which we provided live BD and non-BD fireflies, the snake voluntarily consumed only the former. In the third, a Y-maze experiment, the snake tended to select the chemical trail of BD fireflies more frequently than that of non-BD fireflies. These results demonstrated that R. chiwen discriminates BD fireflies from non-BD fireflies, but the prediction that BDs are involved in this discrimination was not fully supported. To identify the proximate mechanisms of the recognition of novel toxic prey in the R. nuchalis Group, further investigation is necessary.

Fireflies in South East Asia: Species Diversity, Distribution, and Habitat (2015-2021)

Fireflies are one of the most famous luminous insects that emit bioluminescence. The most famous fireflies in Southeast Asia are Pteroptyx , of the order Coleoptera and the Lampyridae family. This review paper combined the data on the species diversity and firefly distribution in Southeast Asian countries such as Malaysia, the Philippines, Indonesia, Cambodia, Myanmar, Singapore, Sri Lanka, Papua New Guinea, Laos, Thailand, and Vietnam published in 2015-2021. Some countries have limited data and no studies to identify firefly species and their habitat from 2015 to 2021; the data before 2015 was used. Furthermore, the lack of studies by Southeast Asian researchers regarding the richness of firefly species has been reviewed. Malaysian and Thailand researchers are among the forerunners in the study related to fireflies in the Southeast Asian region compared to other Southeast Asian countries. Lastly, not much is known about the display trees or habitat of fireflies in many areas such as the Philippines, Indonesia, Cambodia, Myanmar, Singapore, Sri Lanka, Papua New Guinea, Laos, Thailand, and Vietnam. More studies are warranted to be conducted in the future on firefly species and their habitat.

Four New Species of North American Fireflies from Isolated Peatlands with Reference to Species Determination of Photuris Dejean (Coleoptera: Lampyridae)

Four species of fireflies (Coleoptera: Lampyridae) are newly described herein: Photuris anna n. sp., P. sheckscheri n. sp., P. eliza n. sp., P. sellicki n. sp. All were discovered occupying acidic peat wetlands of high ecological quality in the mid-Atlantic and northeastern United States (Delaware, New Jersey, New York). I present a diagnostic phenotypic profile for each as a means to aid in the identification of Photuris fireflies. The association of these species with specific wetland types suggests that the edaphic heterogeneity of wetlands may be a driver of Photuris diversification.

Insect Collections as an Untapped Source of Bioactive Compounds-Fireflies (Coleoptera: Lampyridae) and Cardiotonic Steroids as a Proof of Concept.

Simple SummaryNatural history museums around the world possess extensive collections of dried insects (e.g., beetles, butterflies or flies). Traditionally, museum specimens were mostly studied anatomically for systematic (i.e., how different insects are related) and taxonomic purposes (e.g., description of new species). During the last decades, it has become a common practice to study insect systematics based on DNA extracted from dried museum specimens. Being a highly sought-after prey, many insects evolved powerful toxins to ward off predators. One example is seen in fireflies, a beetle family famous for their ability to emit light. A few species of mainly North American fireflies, however, are known to produce toxins that are called lucibufagins. In this study, we tested if lucibufagins also occur in European species of fireflies. Instead of sampling in the field, we chemically analyzed firefly specimens from museum collections by using a method that preserves the valuable museum specimens. In total, we found lucibufagins in 21 species of fireflies, including specimens that were older than 100 years. Our study emphasizes that insect collections provide a valuable archive of chemical information that can be used for the discovery of novel pharmacologically interesting compounds as well as for addressing ecological questions without destroying valuable specimens.Natural history collections provide an invaluable basis for systematics, ecology, and conservation. Besides being an important source of DNA, museum specimens may also contain a plethora of natural products. Especially, dried insect collections represent a global repository with billions of inventoried vouchers. Due to their vast diversity, insects possess a great variety of defensive compounds, which they either produce autogenously or derive from the environment. Here, we present a case study on fireflies (Coleoptera: Lampyridae), which produce bufadienolides as a defense against predators. These toxins belong to the cardiotonic steroids, which are used for the treatment of cardiac diseases and specifically inhibit the animal enzyme Na+/K+-ATPase. Bufadienolides have been reported from only seven out of approximately 2000 described firefly species. Using a non-destructive approach, we screened 72 dry coleopteran specimens for bufadienolides using HPLC-DAD and HPLC-MS. We found bufadienolides including five novel compounds in 21 species of the subfamily Lampyrinae. The absence of bufadienolides in the phylogenetically related net-winged beetles (Lycidae) and the lampyrid subfamilies Luciolinae and Lamprohizinae indicates a phylogenetic pattern of bufadienolide synthesis. Our results emphasize the value of natural history collections as an archive of chemical information for ecological and evolutionary basic research and as an untapped source for novel bioactive compounds.

Variations in the Distribution and Genetic Relationships among Luciola unmunsana Populations in South Korea

The firefly species Luciola unmunsana was first discovered on the Unmunsan Mountain in Cheongdo-gun, Gyeongsangbuk-do, South Korea and consequently named after the mountain. The population and habitats of this once-abundant species have recently decreased significantly due to light and environmental pollution caused by industrialization and urbanization. This study investigated the distribution and density of L. unmunsana around the ecological landscape conservation area of the Unmunsan Mountain. Additionally, we conducted molecular experiments on regional variations, genetic diversity and phylogenetic relationships among the various populations of L. unmunsana in South Korea. The genetic relationships among populations were also analyzed using mitochondrial DNA by collecting 15 male adults from each of the 10 regions across South Korea selected for analysis. Differences were observed between populations in the east, west and south of the Baekdudaegan Mountain Range. The firefly populations collected from the eastern region, which included Gyeongsang-do, showed a close genetic relationship with fireflies collected from the Unmunsan Mountain. Thus, the findings of this study can be used as baseline data for re-introducing L. unmunsana to the Unmunsan Mountain.

Light from a firefly at temperatures considerably higher and lower than normal

Bioluminescence emissions from a few species of fireflies have been studied at different temperatures. Variations in the flash-duration have been observed and interesting conclusions drawn in those studies. Here we investigate steady-state and pulsed emissions from male specimens of the Indian species Sclerotia substriata at temperatures considerably higher and lower than the ones at which they normally flash. When the temperature is raised to 34 °C, the peak wavelength gets red-shifted and the emitted pulses become the narrowest which broaden considerably thereafter for small increases in temperature; this probably indicates denaturation of the enzyme luciferase catalyzing the light-producing reaction. When the temperature is decreased to the region of 10.5–9 °C, the peak gets blue-shifted and the flash-duration increased abnormally with large fluctuation; this possibly implies cold denaturation of the luciferase. We conclude that the first or hot effect is very likely to be the reason of the species being dark-active on hot days, and the second or cold one is the probable reason for its disappearance at the onset of the winter. Our study makes the inference that these two happenings determine the temperature-tolerance, which plays a major role in the selection of the habitat for the firefly.

The Characteristic of Luciferase cDNA of Lamprigera sp. (Lampyridae: Coleoptera)

Some organisms can emit light naturally. Fireflies are most popular organisms among them. The light is produced in all species of fireflies due to luciferase enzymes. Lamprigera is one of the fireflies genus. Its species Lamprigera sp. is interesting to be studied because it has big larvae dan easily be found on ground at night since it has strong light. Information about the luciferase gene in Lamprigera sp. is restricted. In this study we characterize the luciferase cDNA of Lamprigera sp. collected in Kayu Aro, Kerinci, Jambi. Amplification of Lamprigera’s luciferase cDNA using LF and LR primers produced 367 bp fragments. The similarity levels of Lamprigera’s luciferase cDNA sequences with published Lamprigera yunnana is 83%. This indicates that luciferase cDNA of Lamprigera sp. is different from the published Lamprigera yunnana. However, phylogenetic tree construction shows that Lamprigera sp. have a close relationship with Lamprigera yunnana.

Selection and Validation of Suitable Reference Genes for RT-qPCR Analysis in the Rare Aquatic Firefly Aquatica leii (Coleoptera: Lampyridae).

Simple SummaryThe purpose of this paper was to determine which genes in Aquatica leii, an endemic Chinese firefly, are suitable for use as reference genes in future RT-qPCR studies. This is the first example of an effective knockdown in fireflies and an important methodological advance for continuing research in A. leii. The results of this study will help improve accuracy and reliability to normalize RT-qPCR data in A. leii for further molecular analysis. Since luciferase is very abundant in the adult light organ of fireflies generally, this is an encouraging result and of interest not just for A. leii researchers but other researchers who plan to perform RNAi or RT-qPCR in fireflies, or other nonmodel insects, as well.Aquatica leii Fu and Ballantyne is a species of rare aquatic firefly and endemic in China. It is considered good material to study the molecular mechanism of sexual flash communication systems. To improve conservation and behavioral research strategies, large-scale genetic studies involving gene-expression analysis are required and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is the most commonly used method. However, there have been very few reports on appropriate reference genes in any species of firefly. Here, we evaluated eight widely utilized reference genes including 18S, Actin, Reep5, Odc1, Tub, Gapdh, Ef1a and S27Ae for their expression stabilities in A. leii under three different conditions, i.e., life stage, tissue and dsRNA injection. Based on the gene stability ranking calculated by RefFinder, which integrates four algorithms (geNorm, delta Ct method, NormFinder, and BestKeeper), we recommend S27Ae and Reep5 as the most appropriate reference genes for molecular studies in different life stages; Ef1a and Odc1 for different tissues; Tub and Odc1 for RNAi studies. The most appropriate reference genes in all treatments are S27Ae and Tub. The results of this study will help improve accuracy and reliability to normalize RT-qPCR data in A. leii for further molecular analysis.

On the intertidal firefly genus Micronaspis Green, 1948, with a new species and a phylogeny of Cratomorphini based on adult and larval traits (Coleoptera: Lampyridae)

Although insects are the most diverse evolutionary radiation on Earth, they have rarely occupied marine environments. Understanding the biology of such unique marine associated taxa can lead to insights into the adaptations and limitations of insects inhabiting such an environment. Here, we describe a new species of intertidal fireflies from the northeastern coast of the Atlantic Rainforest, recovered as sister to Micronaspis floridana in the first phylogenetic analysis of Cratomorphini taxa based on morphological data of adults and larvae. We review and redefine the intertidal firefly genus Micronaspis, based on the type species M. floridana, and M. gabrielae sp. nov. We provide descriptions, illustrations and behavioral records for both immature stages and adults, for each species, and indicate putative adaptations to the intertidal environment. Due to intense human occupation along the Atlantic Coast across the Americas, loss of habitat is a concerning issue for conservation efforts of all Micronaspis species. Given the disjunct distribution of the genus (Florida, United States of America and northern Bahamas, and Bahia, Brazil), species diversity could potentially be greater.

Molecular Systematics of the Firefly Genus Luciola (Coleoptera: Lampyridae: Luciolinae) with the Description of a New Species from Singapore.

Simple SummaryFireflies have a scattered distribution in Singapore but are not as uncommon as many would generally assume. A nationwide survey of fireflies in 2009 across Singapore documented 11 species, including “Luciola sp. 2”, which is particularly noteworthy because the specimens were collected from a freshwater swamp forest in the central catchment area of Singapore and did not fit the descriptions of any known Luciola species. Ten years later, we revisited the same locality to collect new specimens and genetic material of Luciola sp. 2. Subsequently, the mitochondrial genome of that population was sequenced and specimens were subjected to rigorous morphological examinations. We then collated published mitogenomes and shorter mitochondrial markers from closely related taxa to infer a phylogeny for the subfamily Luciolinae. Our results reveal that Luciola sp. 2 is both genetically and morphologically distinct from other congeners and is thus described herein as a new species Luciola singapura sp. nov. This marks the first time since 1909 that a new species of luminous firefly has been discovered in Singapore, highlighting the need for continued biodiversity research, even in small, well-studied and highly developed countries such as Singapore that can still harbor undescribed biodiversity.The firefly genus Luciola sensu McDermott contains 282 species that are distributed across major parts of Asia, Europe, Africa, Australia, and the Pacific islands. Due to phenotypic similarities, species identification using external morphological characters can be unreliable for this group. Consequently, decades of piecemeal taxonomic treatments have resulted in numerous erroneous and contentious classifications. Furthermore, our understanding of the group’s evolutionary history is limited due to the lack of a robust phylogenetic framework that has also impeded efforts to stabilize its taxonomy. Here, we constructed molecular phylogenies of Luciola and its allies based on combined mitogenomes and Cytochrome c oxidase subunit 1 (COX1) sequences including a newly sequenced mitogenome of an unidentified taxon from Singapore. Our results showed that this taxon represents a distinct and hitherto undescribed evolutionary lineage that forms a clade with L. filiformis from Japan and L. curtithorax from China. Additionally, the Singaporean lineage can be differentiated from other congeners through several external and internal diagnostic morphological characters, and is thus described herein as a new species. Our phylogeny also strongly supported the paraphyly of Luciola with regard to L. cruciata and L. owadai, which were inferred to be more closely related to the genus Aquatica as opposed to other members of Luciola sensu stricto. The genus Hotaria was inferred as a derived clade within Luciola (sister to L. italica), supporting its status as a subgenus of Luciola instead of a distinct genus. This is the first time since 1909 that a new species of luminous firefly has been discovered in Singapore, highlighting the need for continued biodiversity research, even in small, well-studied and highly developed countries, such as Singapore.

A Description and Examination of Fluorescence in Nine North American Firefly Species (Coleoptera: Lampyridae)

Fluorescence across the family Lampyridae has been documented sporadically but not comprehensively in formal research. Fireflies (Coleoptera: Lampyridae), best known for their bioluminescence, are also fluorescent. This fluorescence has been documented in several genera within the clade but is still an often overlooked aspect of firefly physiology in the common understanding of the species. To this end, the purpose of this study was to document and describe the fluorescence in nine species of North American fireflies, across three genera. Each species was photographed and a description of the fluorescent pattern was provided, as well as measurements of the specific spectral sensitivity of the fluorescent excitation and emission wavelengths. These data are intended to provide an identification guide of sorts to different firefly fluorescence, as well as documenting definitively its presence in several firefly genera.

The size of signal detection and emission organs in a synchronous firefly: sexual dimorphism, allometry and assortative mating.

The size of the organs responsible for emitting and detecting sexual communication signals is a likely target for selection. Communication via bioluminescent signals in synchronous fireflies is a promising model to test hypotheses regarding differences between males and females in the effect of the size of signal emission and detection organs on fitness components. Synchronous firefly species congregate in large numbers during the mating season, displaying bioluminescent signals aimed at potential mates during relatively short nightly periods. Operational sex ratios are male-biased and, thus, the so-called typical sex roles (indiscriminate males and choosy females) are expected to evolve. We studied the synchronous firefly Photinus palaciosi, a species that during the mating season congregates in forests of central Mexico offering a magnificent natural show that attracts numerous tourists. P. palaciosi females have reduced wings (brachyptery) and cannot fly. Our field study tested the hypothesis that the male-biased operational sex ratio and the short daily mating period result in strong male-male competition that selects for males with larger lanterns and larger eyes, and against male mate choice, whereas female-female mate competition is absent and, thus, no selection on lantern or eye size is expected. Even though lantern, eye or body size do not predict the probability of being found in copula for either sex, sexual dimorphism in these features, along with allometric slopes of lantern size and assortative mating in terms of relative lantern size, support not only the hypothesis of intense sexual selection among males, but the possibility of subtle mechanisms of sexual selection among females. Trade-offs between investment in signaling (lanterns) versus detection (eyes) structures, or with pressures different from sexual selection such as those imposed by predators, are also likely to be important in shaping the evolution of sexual signaling in these fireflies.

Spatio-temporal reconstruction of emergent flash synchronization in firefly swarms via stereoscopic 360-degree cameras.

During mating season, males of synchronous firefly species flash in unison within swarms of thousands of individuals. These strongly correlated collective displays have inspired numerous mathematical models to explain how global synchronous patterns emerge from local interactions. Yet, experimental data to validate these models remain sparse. To address this gap, we develop a method for three-dimensional tracking of firefly flashes, using a stereoscopic set-up of 360-degree cameras. We apply this method to record flashing displays of the North American synchronous species Photinus carolinus in its natural habitat as well as within controlled environments, and obtain the three-dimensional reconstruction of flash occurrences in the swarm. Our results show that even a small number of interacting males synchronize their flashes; however, periodic flash bursts only occur in groups larger than 15 males. Moreover, flash occurrences are correlated over several metres, indicating long-range interactions. While this suggests emergent collective behaviour and cooperation, we identify distinct individual trajectories that hint at additional competitive mechanisms. These reveal possible behavioural differentiation with early flashers being more mobile and flashing longer than late followers. Our experimental technique is inexpensive and easily implemented. It is extensible to tracking light communication in various firefly species and flight trajectories in other insect swarms.