Search Results (32)

“Beak larva” is a collective term for four fossil specimens from Kachin amber, which are holometabolan larvae with a forward-projecting beak. This arrangement is very unusual, and so far it has been unclear whether these specimens are larvae of beetles or of lacewings. We present here new details of the mouthparts of one of these larvae based on synchrotron radiation-based X-ray µ-CT (SRµCT) imaging. We can identify that the main part of the beak is formed by the labrum and the labium; the mandibles insert laterally into this beak. The beak has two distinct channels to which the mandibles seem to be connected. The maxillae are tightly connected to the labium and head capsule and have an endite each (unclear if lacinia, galea, or mala), also inserting into the beak. Overall, these details reveal a mouthpart arrangement incompatible with an interpretation as a lacewing. The arrangement is most similar to that in some beetle larvae, namely those of Elateroidea. It most closely resembles that of the larvae of the species-poor sister groups Cerophytidae and Jurasaidae. It seems likely that the beak larvae are closely related to Jurasaidae, possessing an intermediate morphology. The combined data allow us to reconstruct aspects of the entire group, including the beak larvae, Cerophytidae, and Jurasaidae, indicating that they undergo hypermetamorphosis. The latter is most expressed in Jurasaidae. Combined with the paedomorphic female, this group seems to have four rather distinct morphologies and ecologies: (1) early mobile larvae, (2) physogastric, strongly wormlike larvae, (3) “normal”-appearing adult males, and (4) females with another unique morphology. Full article

In the modern fauna, click beetle larvae are important ecosystem components, fulfilling different ecological functions. The fossil record of click beetle larvae is still scarce. Even in the very diverse fauna of the Kachin amber forest (Myanmar, Cretaceous, ca. 100 million years old), only three morphotypes of click beetle larvae have been reported so far. Here, we add a fourth morphotype, characterised by very long setae. The mouthparts indicate a predatory lifestyle. The long and quite stiff-appearing setae might have protected the larvae, for example, when hunting in termite nests, which is a strategy that some extant click beetle larvae apply. This would also imply a closer association with wood and thus a greater likelihood of preservation in amber. Here, we present twelve larvae of this new morphotype, representing two or three possible species, including an ontogenetic series for one of these. Full article

Elateridae (Coleoptera: Elateroidea) are renowned for their clicking mechanism. However, several lineages exhibit body softening that compromises this mechanism, particularly within Plastocerini, Drilini, and Omalisinae. It remains unclear how this body softening is anatomically achieved and which specific structures are degraded in relation to the loss of clicking function. To elucidate the internal morphological adaptations and distinguish them from hard-bodied clicking elateroids, we employed micro-CT to scan Plastocerus thoracicus and reconstruct its thoracic morphology in 3D and quantified key muscle ratios (e.g., M2/M60, M4/M60). Based on our study of P. thoracicus, a detailed comparison was made with previously reported data on Campsosternus auratus (Elateridae) and Cerophytum lii (Cerophytidae). Three-dimensional reconstructions revealed significant structural divergences in P. thoracicus: (1) the clicking-related muscles M4 are markedly weaker than those in Ca. auratus and Ce. Lii. (2) the prosternal process (PP) is extremely narrow. The posterior part of the pronotum exhibits underdeveloped regions, including the posterodorsal evagination (PdE) and the posteromedial process (PmPr). (3) the mesonotum (i.e., the “biological spring” identified in previous studies) is greatly flattened and weakened. (4) the flight muscles (M60, M64) and walking muscles (M74, M75) exhibited significantly bigger volume than Ca. auratus and Ce. lii. These findings provide critical data for understanding the morphological evolution of Elateridae and offer insights into the functional adaptations of the clicking mechanism through comparative anatomy. Full article

Click beetles (Agriotes spp.) are major agricultural pests whose larvae, known as wireworms, cause serious damage to a wide range of crops. Effective management requires a clear understanding of species composition and adult emergence patterns. This study investigated three Agriotes species in central Italy, focusing on their abundance and phenology in the Marche region. Field monitoring was conducted at six sites using pheromone traps from 2024 to 2025. Three species were detected: A. litigiosus, A. brevis, and A. sordidus, with A. litigiosus being the most abundant. Adult emergence displayed species-specific timing, occurring earliest in A. brevis, followed by A. sordidus and subsequently A. litigiosus. These findings highlight the importance of species-specific monitoring to optimize pest-control strategies. A deeper understanding of Agriotes’ flight dynamics can support more effective and sustainable integrated pest management (IPM) strategies, reducing reliance on chemical control and minimizing crop damage. Full article

The genus Parapenia Suzuki from China is revised, with 12 species recognized, including six new species: P. fuxi sp. nov., P. nyuwa sp. nov., P. pangu sp. nov., P. ruihangi sp. nov., P. wuchaoi sp. nov., and P. zhengi sp. nov. In addition, P. sausai Schimmel and P. villosa (Fleutiaux) are newly recorded from China, and P. jagemanni Schimmel syn. nov. is synonymized with P. yunnana Schimmel. Large plate-like sclerites in the bursa copulatrix are consistently present in Parapenia and show diagnostic value for generic delimitation. Comparative morphological studies, particularly of these sclerites, justify the establishment of three new genera distinct from Parapenia: (1) Parapenioides gen. nov., including P. zidani sp. nov.; (2) Megapenia gen. nov., including M. cruciata (Bouwer) comb. nov., type species M. marginalis (Fleutiaux) comb. nov., and M. tianlongi sp. nov.; and (3) Sinopenia gen. nov., including S. significata (Schimmel) comb. nov. A comparative diagnostic table of the four genera, together with a checklist and distribution maps, is provided. Identification keys to Chinese species of Parapenia and Megapenia are also included. This study clarifies the taxonomic complexity of Parapenia and emphasizes the overlooked significance of sclerotized structures in the bursa copulatrix for distinguishing genera within Dimini. Full article

The beetle family Cerophytidae is reported from China for the first time, based on the discovery of Cerophytum lii Qiu & Ruan, sp. nov. and Cerophytum sp., both from Daweishan Mountain in Southeast Yunnan Province. Detailed descriptions and diagnostic illustrations of Cerophytum liisp. nov. are provided, along with an identification key to extant Cerophytum species worldwide. A representative specimen of the new species (a male paratype) underwent micro-computed tomography scanning, enabling three-dimensional reconstruction and virtual dissection of its thoracic morphology. Internal muscular architecture and exoskeletal structures of its thorax are illustrated and described. Comparative morphological analyses revealed convergent evolution in the clicking structures of Cerophytum lii sp. nov. and Campsosternus auratus (Drury), with the latter exhibiting more specialized structural modifications that enhance its jumping performance to a greater degree. In contrast, Cerophytum liisp. nov. exhibits morphological adaptations primarily suited for rapid walking and flight. Full article

Wireworms are the most destructive soil insect pests affecting horticultural crops. The damage often renders them unsuitable for commercial purposes, resulting in substantial economic losses. RNA interference (RNAi) has been broadly used to inhibit gene functions to control insect populations. It employs double-stranded RNA (dsRNA) to knockdown essential genes in target organisms, rendering them incapable of development or survival. Although it is a robust approach, the primary challenges are identifying effective target genes and delivering their dsRNA into wireworms. Thus, the present study established a liquid ingestion methodology that efficiently delivers dsRNA into wireworms. We then investigated the effects of four target genes on wireworm mortality. The highest mortality rate reached 50% when the gene encoding vacuolar ATPase subunit A was targeted. Its transcript content in the fed wireworms was also significantly reduced. The mortality rates of the other three target genes of vacuolar ATPase subunit E, beta-actin, and chitin synthase 1 were 28%, 33%, and 35%, respectively. This is the first report demonstrating an efficient feeding methodology and the silencing of target genes in wireworms. Our findings indicate that RNAi is an effective alternative method for controlling the wireworm pest, and can be used to develop field treatment strategies. Full article

Low-cost monitoring tools are needed to implement IPM in arable crops. YATLORf (Yf) traps baited with respective synthetic pheromone lures have proven to be a reliable tool for monitoring Agriotes spp., Europe’s most harmful soil pests. To optimize Yf use, we studied the effect of lure position in the trap and crop density on trap performance. Yf management detail was studied between 2000–2003 and 2014–2016 in various countries, with the traps being arranged in blocks. Each block contained one trap per treatment (i.e., lure position) under study. It was ascertained that lure attractant capacity can vary greatly with the lure’s position in the trap and the extent of vegetation. Information for making practical decisions is given. The ‘low’ lure position is suitable for all species in all field conditions, and is the best choice for A. brevis. Lures for A. brevis and A. lineatus need to be placed in the low position when the field has no or sparse vegetation cover. The ‘high’ lure position is unsuitable for A. brevis and A. obscurus, and should be considered for some species only. There are no restrictions on position for catching A. sordidus, i.e., any position is suitable. Dense vegetation (e.g., wheat) reduced the Yf trap’s potential for catching A. sordidus. Placing the trap just outside the field, or in a nearby field with bare/sparse vegetation, maintained the maximum catching potential. Vegetation density also influenced beetle sex ratio, with A. brevis and A. sordidus females always found in traps placed in fields with bare or low-density vegetation. Our findings have made it possible to obtain consistent monitoring outputs and to begin studies on multi-baiting the same trap, which can significantly reduce monitoring costs. Full article

Wireworm, the larval stages of click beetles, are a serious pest of tubers, brassicas and other important commercial crops throughout the northern hemisphere. No effective control agent has been developed specifically for them, and many of the pesticides marketed as having secondary application against them have been withdrawn from EU and Asian markets. Metarhizium brunneum, an effective entomopathogenic fungus, and its derived volatile metabolites are known to be effective plant biostimulants and plant protectants, although field efficacy has yet to be validated. Field validation of a combined M. brunneum and derived VOC treatments was conducted in Wales, UK, to assess the effects of each as a wireworm control agent and biostimulant. Plots were treated with Tri-Soil (Trichoderma atroviridae), M. brunneum, 1-octen-3-ol or 3-octanone, or combinations thereof. Treatments were applied subsurface during potato seeding (n = 52), and potatoes were harvested at the end of the growing season. Each potato was weighed individually and scored for levels of wireworm damage. Applications of both the VOCs and the M. brunneum individually were found to significantly decrease wireworm burden (p < 0.001). Combinations of M. brunneum and 3-octanone were also found to significantly decrease wireworm damage (p < 0.001), while no effect on yield was reported, resulting in an increased saleable mass over controls (p < 0.001). Herein, we present a novel ‘stimulate and deter’ wireworm control strategy that can be used to significantly enhance saleable potato yields and control wireworm populations, even under high pest pressure densities. Full article

The family Elateridae, known as click beetles, is a mega-diverse lineage of Coleoptera. Wireworms are the larval stage of click beetles, which are generalist herbivores and which are recognized as economically important pests of crops. To more effectively control and monitor wireworms, it is crucial to understand the genetics, taxonomy and phylogenetics of Elateridae. Here, we sequenced and characterized three complete mitochondrial genomes (mitogenomes) from the subfamily Elaterinae using a next-generation sequencing approach. In addition, we provided the annotated mitogenomes of the newly sequenced species, namely Parasilesis musculus (Candèze, 1873), Melanotus cribricollis Candèze, 1860 and Glyphonyx sp., and compared their arrangement with other closely related species. The secondary structures of tRNA genes and rRNA genes were predicted. Combined with the published mitogenomes of elaterid species, we reconstructed the phylogenetic framework for Elateridae under maximum likelihood and Bayesian inference methods using nucleotide and amino acid sequence datasets separately. The results from the Bayesian analysis based on the nucleotide dataset PCGRNA including all 37 mitochondrial genes were congruent with previous studies. Within the monophyletic Elateridae, two main clades were recovered. The first clade included Elaterinae and Melanotus. The second clade consisted of the remaining subfamilies. Physodactylinae and Cardiophorinae formed a sister group. Agrypninae was monophyletic. A subclade comprised Negastriinae and Dendrometrinae. Full article

The click beetles (Elateridae) originated in the Mesozoic and recently form a relatively large family with approximately 10,000 described species worldwide. However, the Mesozoic, and particularly Cretaceous, click beetle fauna remains very poorly known. Here we describe Burmogonus cretaceus gen. et sp. nov. based on a single, relatively well-preserved, specimen from the mid-Cretaceous Burmese amber. This species can be assigned with confidence to the subfamily Elaterinae, and based on the supra-antennal carinae being incomplete across the head and directed to the labrum, the shape of metacoxal plates, and simple tarsi, we tentatively place it in the tribe Elaterini. We discuss the morphology of a new genus and other Elaterinae described from Burmese amber. Full article

The soft-bodied click-beetle genus Malacogaster Bassi, 1834 from the Mediterranean region has never been taxonomically revised to date. Information on its morphology, intra- and interspecific variability, systematics and distribution is fragmented and most species have not been properly studied since their description. Therefore, in this study we summarize all available information on the genus Malacogaster. Altogether, we recognize 10 valid species from the area including the Canary Islands, Iberian Peninsula, Balearic Islands, northern coast of Africa, Sardinia, and Sicily. Malacogaster ruficollis Dodero, 1925, stat. nov., which was originally described as a variety of M. bassii Lucas, 1870 and later synonymized with it, is considered a separate species. Malacogaster parallelocollis Reitter, 1894, syn. nov. and M. olcesei var. reductus Pic, 1951, syn. nov. are synonymized with M. maculiventris Reitter, 1894. Malacogaster notativentris Pic, 1951, syn. nov. and M. olcesei Pic, 1951, syn. nov. are synonymized with M. passerinii Bassi, 1834. Lectotypes are designated for M. maculiventris Reitter, 1894, M. nigripes heydeni Reitter, 1894, M. parallelocollis Reitter, 1894, M. thoracica Redtenbacher, 1858, M. olcesei Pic, 1951, and M. rubripes Peyerimhoff, 1949 to fix their identity. Full article

The rhizosphere is where plant roots, physical soil, and subterranean organisms interact to contribute to soil fertility and plant growth. In agroecosystems, the nature of the ecological interactions within the rhizosphere is highly dynamic due to constant disruptions from agricultural practices. The concept of integrated pest management (IPM) was developed in order to promote an approach which is complementary to the environment and non-target organisms, including natural enemies, by reducing the sole reliance on synthetic pesticides to control pests. However, some of the implemented integrated cultural and biological control practices may impact the rhizosphere, especially when targeting subterranean pests. Wireworms, the larval stage of click beetles (Coleoptera: Elateridae), are generalist herbivores and a voracious group of pests that are difficult to control. This paper introduces some existing challenges in wireworm IPM, and discusses the potential impacts of various control methods on the rhizosphere. The awareness of the potential implications of different pest management approaches on the rhizosphere will assist in decision-making and the selection of the control tactics with the least long-term adverse effects on the rhizosphere. Full article

We investigated and described the thoracic structures, jumping mechanism, and promesothoracic interlocking mechanism of the click beetle Campsosternus auratus (Drury) (Elateridae: Dendrometrinae). Two experiments were conducted to reveal the critical muscles and sclerites involved in the jumping mechanism. They showed that M2 and M4 are essential clicking-related muscles. The prosternal process, the prosternal rest of the mesoventrite, the mesoventral cavity, the base of the elytra, and the posterodorsal evagination of the pronotum are critical clicking-related sclerites. The destruction of any of these muscles and sclerites resulted in the loss of normal clicking and jumping ability. The mesonotum was identified as a highly specialized saddle-shaped biological spring that can store elastic energy and release it abruptly. During the jumping process of C. auratus, M2 contracts to establish and latch the clicking system, and M4 contracts to generate energy. The specialized thoracic biological springs (e.g., the prosternum and mesonotum) and elastic cuticles store and abruptly release the colossal energy, which explosively raises the beetle body in a few milliseconds. The specialized trigger muscle for the release of the clicking was not found; our study supports the theory that the triggering of the clicking is due to the building-up of tension (i.e., elastic energy) in the system. Full article

Sex pheromones are commonly used in traps to monitor populations and movements of male click beetles, but to date few attractants have been identified for females. Notable exceptions are plant-derived kairomones for female Agriotes brevis and A. ustulatus, allowing the monitoring of both males and females of these species with lures containing both pheromones and plant volatiles. The attractiveness of these plant volatiles for two congeners, A. obscurus and A. lineatus, which are agricultural pests in Europe and North America, was evaluated in the current study. Both the four-component MINIM plant-derived lure for A. brevis, and the blend of (E)-anethol and (E)-cinnamaldehyde for A. ustulatus, were not attractive to A. obscurus and A. lineatus, and instead appeared to reduce captures—both when compared to blank controls, and when blended with and compared to the sex pheromones of these species. This was most pronounced in A. obscurus, where (E)-anethol and (E)-cinnamaldehyde reduced male captures by 43 and 37%, respectively. Combining the pheromones of A. obscurus and A. lineatus reduced captures of these species by 77 and 19%, respectively, compared to these pheromones singly. This suggests that attractants for female click beetles can be highly species-specific, and that the blending of pheromones of congeneric species with each other, or with plant volatiles, can reduce captures. Further research into developing such attractants for economic species is urgently needed. Full article