Four species of Limonius wireworms (Coleoptera: Elateridae), L. californicus, L. canus, L. infuscatus and L. agonus, are serious crop pests in North America. Limoniic acid, (E)-4-ethyloct-4-enoic ...acid, has been reported as a sex pheromone component of female L. californicus and L. canus, and a sex attractant for male L. infuscatus. In the same study, both limoniic acid and the analog (E)-5-ethyloct-4-enoic acid were highly attractive in field experiments. Moreover, six carboxylic acids in headspace volatiles of Limonius females elicited responses from male antennae but were not tested for behavioral activity. Here, we report trap catch data of Limonius spp. obtained in field experiments at 27 sites across North America. All four Limonius species were attracted to limoniic acid and to the analog but not to the carboxylic acids. Adding these carboxylic acids to limoniic acid, or to the analog, reduced its attractiveness. In dose–response studies, trap lures containing 0.4 mg or 4 mg of limoniic acid afforded large captures of L. californicus and L. infuscatus. Neither limoniic acid nor the analog were deterrent to other elaterid pest species. The broad attractiveness of limoniic acid to Limonius spp., and its non-deterrent effect on heterogeners, may facilitate the development of generic pheromone-based monitoring and management tools for multiple click beetle species.
Abstract
The click‐beetles (Elateridae) are a species‐rich beetle family that is easily recognizable. They are distributed in all zoogeographical regions with over 11,000 species. Comparative studies ...of the structural characteristics of mitochondrial genomes (mitogenomes), as well as phylogenetic relationships of click‐beetles, can improve our understanding of mitogenomic evolution. In this study, we determined four mitogenomes from Elateridae by next‐generation sequencing. The four mitogenomes were 16,005 to 16,930 bp in length with 37 typical genes and a control region (A + T‐rich region). Combined with previously reported elaterid mitogenomes, all PCGs initiate with either the standard start codon of ATN or TTG. According to the nonsynonymous/synonymous mutation ratio (Ka/Ks) of all PCGs, the highest and the lowest evolutionary rates were found for
atp8
and
cox1
, respectively. Among the control regions of the four mitogenomes, several different patterns and numbers of tandem repeats were identified, which was the primary cause of the length variation in control regions. Phylogenetic analyses were conducted based on 13 protein‐coding genes and two ribosomal RNA genes from 33 species of Elateridae and two outgroups. The Bayesian inference and maximum likelihood trees had an identical topological structure. The monophyly of Cardiophorinae, Agrypninae and Elaterinae was recovered with high support in all topologies, and the Tetralobinae was placed as the earliest branch in the Elateridae. Expanding the availability of mitogenomic and genomic data from a broader range of click‐beetles could provide more clarity on the disputed relationships among subfamilies within Elateridae.
Highlights
Four novel mitogenomes from Elateridae were sequenced and determined using next‐generation sequencing.
All available mitogenomes of Elateridae were comparative and analyses to better understand of their mitogenomic evolution patterns.
The monophyly of Cardiophorinae, Agrypninae and Elaterinae was recovered with high support.
•Our study documents factors that affect wireworms in the Pacific Northwestern USA.•Wireworms were more abundant in spring wheat compared to winter wheat.•Native grassland habitats serve as good ...reservoirs for wireworms.•Soil moisture and acidification strongly mediate wireworm communities.•Understanding landscape-scale distributions of wireworms can improve IPM.
Characterizing the composition of pest communities across variable cropping landscapes is critical for developing integrated management programs due to variation across species in their ecology and impacts on crops. Wireworms, the soil-dwelling larvae of click beetles, have resurged as major pests of cereal crops in the Pacific Northwestern United States, but knowledge of the composition of wireworm communities across cereal-growing landscapes remains limited. Here, we conducted a large-scale field survey of wireworms across a broad region in the Pacific Northwest. We identified a total of 13 wireworm species across samples taken from 160 fields in Washington, Oregon, and Idaho. The most common species were Limonius infuscatus, L. californicus, and Selatosomus pruininus, which together represented approximately 90% of collected larvae. Wireworm communities were more abundant and diverse in spring wheat and conservation reserve program compared with winter wheat fields. Interestingly, L. californicus was the only species that was more abundant in cultivated wheat crops than in native grass fields, suggesting that this species persists in crop habitats throughout its life cycle and thus might exert stronger impacts on winter crops compared to other species. Our results indicate that Limonius species are distributed mostly in the intermediate and higher precipitation zones or in irrigated fields, while S. pruininus is confined to drier regions. As the dominant wireworm species, the diversity of wireworm communities, and total wireworm abundance varied across crops, landscapes, and climatic regions, management practices should vary across regions for maximum effectiveness.
Wireworms are the larval stage of click beetles (Coleoptera: Elateridae), and some of their species are serious pests of many crops. In the present study, we evaluated the efficacy of naturally ...occurring and commercial entomopathogenic nematode species against the sugar beet wireworm, Limonius californicus (Mannerheim), in the laboratory. First, efficacies of Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) collected from an irrigated (S. feltiae-SSK) and a dryland (S. feltiae-SSC) field and the two commercial entomopathogenic nematode species, S. carpocapsae (Weiser) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), were examined. Efficacies of the two field-collected S. feltiae isolates were also compared against a commercial S. feltiae strain. In the first bioassay, S. feltiae-SSK caused 63.3% wireworm mortality, followed by 30% caused by S. carpocapsae, 23.3% by S. feltiae-SSC, and 6.7% by H.bacteriophora. In the second assay, S. feltiae-SSK killed 56.7% of the wireworms, ≈2.1- and ≈5.7-fold higher than S. feltiae-SSC and the commercial isolate, respectively.
The subfamily Denticollinae is a taxonomically diverse group in the family Elateridae. Denticollinae includes many morphologically similar species and crop pests, as well as many undescribed species ...at each local fauna. To construct a rapid and reliable identification system for this subfamily, the effectiveness of molecular species identification was assessed based on 421 cytochrome c oxidase subunit I (COI) sequences of 84 morphologically identified species. Among the 84 morphospecies, molecular species identification of 60 species (71.4%) was consistent with their morphological identifications. Six cryptic and/or pseudocryptic species with large genetic divergence (>5%) were confirmed by their sympatric or allopatric distributions. However, 18 species, including a subspecies, had ambiguous genetic distances and shared overlapping intra- and interspecific genetic distances (range: 2.12%-3.67%) suggesting incomplete lineage sorting, introgression of mitochondrial genome, or affection by endosymbionts, such as Wolbachia infection, between species and simple genetic variation within species. In this study, we propose a conservative threshold of 3.6% for convenient molecular operational taxonomic unit (MOTU) identification in the subfamily Denticollinae based on the results of pairwise genetic distances analyses using neighbor-joining, mothur, Automatic Barcode Gap Discovery analysis, and tree-based species delimitation by Poisson Tree Processes analysis. Using the 3.6% threshold, we identified 87 MOTUs and found 8 MOTUs in the interval between 2.5% to 3.5%. Evaluation of MOTUs identified in this range requires integrative species delimitation, including review of morphological and ecological differences as well as sensitive genetic markers. From this study, we confirmed that COI sequence is useful for reassessing species diversity for polymorphic and polytypic species occurring in sympatric and allopatric distributions, and for a single species having an extensively large habitat.
Click-beetles (Coleoptera: Elateridae) are an abundant, diverse, and economically important beetle family that includes bioluminescent species. To date, molecular phylogenies have sampled relatively ...few taxa and genes, incompletely resolving subfamily level relationships. We present a novel probe set for anchored hybrid enrichment of 2260 single-copy orthologous genes in Elateroidea. Using these probes, we undertook the largest phylogenomic study of Elateroidea to date (99 Elateroidea, including 86 Elateridae, plus 5 non-elateroid outgroups). We sequenced specimens from 88 taxa to test the monophyly of families, subfamilies and tribes. Maximum likelihood and coalescent phylogenetic analyses produced well-resolved topologies. Notably, the included non-elaterid bioluminescent families (Lampyridae + Phengodidae + Rhagophthalmidae) form a clade within the otherwise monophyletic Elateridae, and Sinopyrophoridae may not warrant recognition as a family. All analyses recovered the elaterid subfamilies Elaterinae, Agrypninae, Cardiophorinae, Negastriinae, Pityobiinae, and Tetralobinae as monophyletic. Our results were conflicting on whether the hypnoidines are sister to Dendrometrinae or Cardiophorinae + Negastriinae. Moreover, we show that fossils with the eucnemid-type frons and elongate cylindrical shape may belong to Eucnemidae, Elateridae: Thylacosterninae, ancestral hard-bodied cantharoids or related extinct groups. Proposed taxonomic changes include recognition of Plastocerini as a tribe in Dendrometrinae and Hypnoidinae stat. nov. as a subfamily within Elateridae.
Mitochondrial genome organization in the Elateroidea superfamily (Coleoptera), which include the main families of bioluminescent beetles, has been poorly studied and lacking information about ...Phengodidae family. We sequenced the mitochondrial genomes of Neotropical Lampyridae (Bicellonycha lividipennis), Phengodidae (Brasilocerus sp.2 and Phrixothrix hirtus) and Elateridae (Pyrearinus termitilluminans, Hapsodrilus ignifer and Teslasena femoralis). All species had a typical insect mitochondrial genome except for the following: in the elaterid T. femoralis genome there is a non-coding region between NADH2 and tRNA-Trp; in the phengodids Brasilocerus sp.2 and P. hirtus genomes we did not find the tRNA-Ile and tRNA-Gln. The P. hirtus genome showed a ~1.6kb non-coding region, the rearrangement of tRNA-Tyr, a new tRNA-Leu copy, and several regions with higher AT contents. Phylogenetics analysis using Bayesian and ML models indicated that the Phengodidae+Rhagophthalmidae are closely related to Lampyridae family, and included Drilus flavescens (Drilidae) as an internal clade within Elateridae. This is the first report that compares the mitochondrial genomes organization of the three main families of bioluminescent Elateroidea, including the first Neotropical Lampyridae and Phengodidae. The losses of tRNAs, and translocation and duplication events found in Phengodidae mt genomes, mainly in P. hirtus, may indicate different evolutionary rates in these mitochondrial genomes. The mitophylogenomics analysis indicates the monophyly of the three bioluminescent families and a closer relationship between Lampyridae and Phengodidae/Rhagophthalmidae, in contrast with previous molecular analysis.
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•First Phengodidae mitochondrial genome annotation•Phengodidae mt genomes show a tRNA rearrangement and gene/tRNA duplication.•Phengodidae+Rhagophthalmidae are more closely related to Lampyridae than to Elateridae.
Beetle larvae show high diversity in forms and ecological roles. Beetle larvae are often roughly categorised into certain larval types, for example: campodeiform, onisciform, scarabeiform, or ...elateriform. Larvae of the latter type are virtually absent from the fossil record. Here, we report three amber pieces from Cretaceous Kachin amber, Myanmar (about 100 million years old) that together include nine elateriform beetle larvae. One of the amber pieces has a single specimen included. The specimen is interpreted as a larva of Elateridae, the group of click beetles, possibly of the ingroup Elaterinae; yet accessible details are limited. Eight specimens within the other two amber pieces show certain similarities with larvae of Elateridae, but show significant differences in the trunk end, which bears two lobes armed with hooks in these fossils. This very specific structure is well known in modern larvae of Ptilodactylidae (toed-winged beetles). Therefore, the fossils are interpreted as larvae of Ptilodactylidae. Both types of here reported elateriform larvae represent the first fossil record of larvae of their respective groups. It is well known that larval morphology does not evolve in concert with adult morphology, and a modern-type morphology of the one may precede that of the other. Hence, the new fossils are important indicators of the appearance of the modern larval morphologies of their respective lineages. We also briefly discuss the fossil record of larvae of Elateriformia (of which Elateridae and Ptilodactylidae are ingroups) in general.
Vision plays a vital biological role in organisms, which depends on the visual pigment molecules (opsin plus chromophore). The expansion or reduction of spectral channels in the organisms is ...determined by distinct opsin classes and copy numbers resulting from duplication or loss. Within Coleoptera, the superfamily Elateroidea exhibits a great diversity of morphological and physiological characteristics, such as bioluminescence, making this group an important model for opsin studies. While molecular and physiological studies have been conducted in Lampyridae and Elateridae, other families remain unexplored. Here, we reused transcriptome datasets from Elateroidea species, including members of Elateridae, Lampyridae, Phengodidae, Rhagophthalmidae, Cantharidae, and Lycidae, to detect the diversity of putative opsin genes in this superfamily. In addition, we tested the signature of sites under positive selection in both ultraviolet (UV)‐ and long‐wavelength (LW)‐opsin classes. Although the visual system in Elateroidea is considered simple, we observed events of duplication in LW‐ and UV‐opsin, as well as the absence of UV‐opsin in distinct families, such as larval Phengodidae individuals. We detected different copies of LW‐opsins that were highly expressed in the eyes of distinct tribes of fireflies, indicating the possible selection of each copy during the evolution of the sexual mating to avoid spectrum overlapping. In Elateridae, we found that the bioluminescent species had a distinct LW‐opsin copy compared with the non‐bioluminescent species, suggesting events of duplication and loss. The signature of positive selection showed only one residue associated with the chromophore binding site in the Elateroidea, which may produce a bathochromic shift in the wavelength absorption spectra in this family. Overall, this study brings important content and fills gaps regarding opsin evolution in Elateroidea.
Duplication events in LW‐ and UV‐opsin and the absence of UV‐opsin transcripts in specific families like Phengodidae in Elateroidea.
Highly expressed LW‐opsin copies in firefly tribes may indicate selection during sexual mating evolution to avoid spectrum overlap.
Bioluminescent Elateridae species exhibit distinct LW‐opsin copies, suggesting duplication and loss events.
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