Toxicity of clothianidin to common Eastern North American fireflies

Background Previous research suggests that fireflies (Coleoptera: Lampyridae) are susceptible to commonly used insecticides. In the United States, there has been a rapid and widespread adoption of neonicotinoid insecticides, predominantly used as seed coatings on large-acreage crops like corn, soy, and cotton. Neonicotinoid insecticides are persistent in soil yet mobile in water, so they have potential to contaminate firefly habitats both in and adjacent to application sites. As a result, fireflies may be at high risk of exposure to neonicotinoids, possibly jeopardizing this already at-risk group of charismatic insects. Methods To assess the sensitivity of fireflies to neonicotinoids, we exposed larvae of Photuris versicolor complex and Photinus pyralis to multiple levels of clothianidin-treated soil and monitored feeding behavior, protective soil chamber formation, intoxication, and mortality. Results Pt. versicolor and Pn. pyralis larvae exhibited long-term intoxication and mortality at concentrations above 1,000 ng g−1 soil (1 ppm). Under sub-lethal clothianidin exposure, firefly larvae fed less and spent less time in protective soil chambers, two behavioral changes that could decrease larval survival in the wild. Discussion Both firefly species demonstrated sub-lethal responses in the lab to clothianidin exposure at field-realistic concentrations, although Pt. versicolor and Pn. pyralis appeared to tolerate higher clothianidin exposure relative to other soil invertebrates and beetle species. While these two firefly species, which are relatively widespread in North America, appear somewhat tolerant of neonicotinoid exposure in a laboratory setting, further work is needed to extend this conclusion to wild populations, especially in rare or declining taxa.

Improving the Stability of Protein–Protein Interaction Assay FlimPIA Using a Thermostabilized Firefly Luciferase

The protein–protein interaction assay is a key technology in various fields, being applicable in drug screening as well as in diagnosis and inspection, wherein the stability of assays is important. In a previous study, we developed a unique protein–protein interaction assay “FlimPIA” based on the functional complementation of mutant firefly luciferases (Fluc). The catalytic step of Fluc was divided into two half steps: D-luciferin was adenylated in the first step, while adenylated luciferin was oxidized in the second step. We constructed two mutants of Fluc from Photinus pyralis (Ppy); one mutant named Donor is defective in the second half reaction, while the other mutant named Acceptor exhibited low activity in the first half reaction. To date, Ppy has been used in the system; however, its thermostability is low. In this study, to improve the stability of the system, we applied Fluc from thermostabilized Luciola lateralis to FlimPIA. We screened suitable mutants as probes for FlimPIA and obtained Acceptor and Donor candidates. We detected the interaction of FKBP12-FRB with FlimPIA using these candidates. Furthermore, after the incubation of the probes at 37°C for 1 h, the luminescence signal of the new system was 2.4-fold higher than that of the previous system, showing significant improvement in the stability of the assay.

Type designations for fireflies (Coleoptera: Lampyridae) of the Biologia Centrali Americana Gorham, 1881 housed in the Natural History Museum, London

The Biologia Centrali Americana (B.C.A.) is comprised of eight volumes that deal specifically with Coleoptera. These volumes were split into 18 parts and were published between 1879 and 1911. The family Lampyridae was treated in two parts, the main text (1881) with a supplement (1884). Within volume three, part 2, Gorham lists ~90 species in 14 genera, not including the Phengodini subfamily. Of these, Gorham provided original descriptions for 37 species. During recent research visits (2018 and 2020) the authors were able to study material pertinent to the B.C.A. We were able to confidently designate holotypes, lectotypes, and paralectotypes following ICZN articles 73.1 and 74.1 within these species. Two species described by Gorham (1881) are not treated here. Phaenolis nirgricollis was located with a single specimen, already designate as the holotype. Two female syntypes of Photinus consanguineous were located, however Oliver (1907) synonymized these females with Photinus pyralis. These designations contribute to a larger taxonomic effort to stabilize the nomenclature of this group. The species described in the supplement will be treated in a future work. Subfamilies are listed according to Martin et al. (2019) and genera/species within each subfamily are listed according to the order in Gorham (1881).

On the inference of a southern origin of the North American firefly Photinus pyralis

The firefly Photinus pyralis inhabits a wide range of latitudinal and ecological niches, with populations living from temperate to tropical habitats. Its ample geographic distribution makes this species an ideal system for the study of local adaptation and demographic inference of wild populations. Therefore, in this study we modelled and inferred different demographic scenarios for North American populations of P. pyralis, collected from Texas to New Jersey. To do this, we used a combination of ABC techniques (for multi-population/colonization analyses), and likelihood inference (dadi) for single-population demographic inference, which proved useful with our RAD data.We uncovered that the most ancestral North American population lays in Texas, which further colonized the Central region of the US and more recently the North Eastern coast. Our study confidently rejects a demographic scenario where the North Eastern populations colonized more southern populations until reaching Texas. Our results suggest that P. pyralis originated in Central- or South America, followed by migration events that populated northern latitudes. Finally, modelling the demographic history of North American P. pyralis serves as a null model of nucleotide diversity patterns, which will inform future studies of adaptation, not only in P. pyralis, but also in other North American taxa.

Firefly genomes illuminate parallel origins of bioluminescence in beetles

Fireflies and their luminous courtships have inspired centuries of scientific study. Today firefly luciferase is widely used in biotechnology, but the evolutionary origin of bioluminescence within beetles remains unclear. To shed light on this long-standing question, we sequenced the genomes of two firefly species that diverged over 100 million-years-ago: the North American Photinus pyralis and Japanese Aquatica lateralis. To compare bioluminescent origins, we also sequenced the genome of a related click beetle, the Caribbean Ignelater luminosus, with bioluminescent biochemistry near-identical to fireflies, but anatomically unique light organs, suggesting the intriguing hypothesis of parallel gains of bioluminescence. Our analyses support independent gains of bioluminescence in fireflies and click beetles, and provide new insights into the genes, chemical defenses, and symbionts that evolved alongside their luminous lifestyle.

Firefly genomes illuminate parallel origins of bioluminescence in beetles

Fireflies and their fascinating luminous courtships have inspired centuries of scientific study. Today firefly luciferase is widely used in biotechnology, but the evolutionary origin of their bioluminescence remains unclear. To shed light on this long-standing question, we sequenced the genomes of two firefly species that diverged over 100 million-years-ago: the North AmericanPhotinus pyralisand JapaneseAquatica lateralis.We also sequenced the genome of a related click-beetle, the CaribbeanIgnelater luminosus,with bioluminescent biochemistry near-identical to fireflies, but anatomically unique light organs, suggesting the intriguing but contentious hypothesis of parallel gains of bioluminescence. Our analyses support two independent gains of bioluminescence between fireflies and click-beetles, and provide new insights into the genes, chemical defenses, and symbionts that evolved alongside their luminous lifestyle.One Sentence Summary:Comparative analyses of the first linkage-group-resolution genomes of fireflies and related bioluminescent beetles address long-standing questions of the origin and evolution of bioluminescence and its associated traits.

Bioluminescence as a tool in molecular biology

Bioluminescence has been studied for many years by scientists. There are numerous mechanisms of that phenomenon; among them bacterial bioluminescence is the most frequently found in nature. This type of bioluminescence is determined by the appearance of lux operon, which encodes all elements necessary to produce light emission and it does not require any additional substrates supply. Another commonly found example of bioluminescence mechanism is performed by Photinus pyralis. Luciferase of P. pyralis named FLuc requires D-luciferin as a substrate. Bioluminescence is also characteristic for many deep-sea organisms. Most of them are based on oxidation reaction of coelenterazine to coelenteramide mediated by RLuc or GLuc luciferases. Due to the variety of bioluminescence mechanisms in nature, it has become possible to apply them in many sensitive methods that can be used in molecular biology and medicine. The most significant application of bioluminescence is BLI (bioluminescence imaging). This method is cheap and nontoxic which allows both in vitro and in vivo imaging. BLI applications include, e.g. protein-protein interactions, stem cells labeling, tracking of viral, bacterial, fungal and parasitical infections, and carcinogenesis analyses. Bioluminescence has also been used in the creation of modified cell systems capable of light emission in response to certain analytes and thus very sensitive biosensors have been generated. Other important areas of bioluminescence application are immunoassays, ATP assays, and BART analysis (bioluminescent assay in Real-Time) – a very sensitive technique which allows scientists to estimate nucleic acids amplification.