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Scientific Reports Jul 2016Various types of weapon traits found in insect order Coleoptera are known as outstanding examples of sexually selected exaggerated characters. It is known that the sex...
Molecular cloning and functional characterization of the sex-determination gene doublesex in the sexually dimorphic broad-horned beetle Gnatocerus cornutus (Coleoptera, Tenebrionidae).
Various types of weapon traits found in insect order Coleoptera are known as outstanding examples of sexually selected exaggerated characters. It is known that the sex determination gene doublesex (dsx) plays a significant role in sex-specific expression of weapon traits in various beetles belonging to the superfamily Scarabaeoidea. Although sex-specific weapon traits have evolved independently in various Coleopteran groups, developmental mechanisms of sex-specific expression have not been studied outside of the Scarabaeoidea. In order to test the hypothesis that dsx-dependent sex-specific expression of weapon traits is a general mechanism among the Coleoptera, we have characterized the dsx in the sexually dimorphic broad-horned beetle Gnatocerus cornutus (Tenebrionidea, Tenebirionidae). By using molecular cloning, we identified five splicing variants of Gnatocerus cornutus dsx (Gcdsx), which are predicted to code four different isoforms. We found one male-specific variant (GcDsx-M), two female-specific variants (GcDsx-FL and GcDsx-FS) and two non-sex-specific variants (correspond to a single isoform, GcDsx-C). Knockdown of all Dsx isoforms resulted in intersex phenotype both in male and female. Also, knockdown of all female-specific isoforms transformed females to intersex phenotype, while did not affect male phenotype. Our results clearly illustrate the important function of Gcdsx in determining sex-specific trait expression in both sexes.
Topics: Animals; Animals, Genetically Modified; Cells, Cultured; Cloning, Molecular; Coleoptera; DNA-Binding Proteins; Drosophila Proteins; Evolution, Molecular; Female; Gene Expression Regulation, Developmental; Insect Proteins; Larva; Male; Protein Isoforms; Sex Characteristics; Sex Differentiation
PubMed: 27404087
DOI: 10.1038/srep29337 -
Pest Management Science Jul 2012Bark beetles, especially Dendroctonus species, are considered to be serious pests of the coniferous forests in North America. Bark beetle forest pests undergo population... (Review)
Review
Bark beetles, especially Dendroctonus species, are considered to be serious pests of the coniferous forests in North America. Bark beetle forest pests undergo population eruptions, causing region wide economic losses. In order to save forests, finding new and innovative environmentally friendly approaches in wood-boring insect pest management is more important than ever. Several biological control methods have been attempted over time to limit the damage and spreading of bark beetle epidemics. The use of entomopathogenic microorganisms against bark beetle populations is an attractive alternative tool for many biological control programmes in forestry. However, the effectiveness of these biological control agents is strongly affected by environmental factors, as well as by the susceptibility of the insect host. Bark beetle susceptibility to entomopathogens varies greatly between species. According to recent literature, bark beetles are engaged in symbiotic relationships with fungi and bacteria. These types of relationship are very complex and apparently involved in bark beetle defensive mechanisms against pathogens. The latest scientific discoveries in multipartite symbiosis have unravelled unexpected opportunities in bark beetle pest management, which are discussed in this article.
Topics: Animals; Bacteria; Coleoptera; Fungi; Pest Control, Biological; Symbiosis; Trees
PubMed: 22566204
DOI: 10.1002/ps.3307 -
Current Biology : CB Nov 2019The manipulation of animal behavior by parasitic organisms is one of the most complex adaptations to have arisen via natural selection. Among the most impressive...
The manipulation of animal behavior by parasitic organisms is one of the most complex adaptations to have arisen via natural selection. Among the most impressive examples of behavioral manipulation are the zombie-ant fungi [1]. In this association, ants are controlled to leave the colony and perform a stereotyped death grip behavior, where they bite onto vegetation over foraging trails, before being killed for the post mortem fungal growth. Manipulation functions to provide a platform outside the nest, from which fungal parasites actively shoot out spores, targeting foraging ants because within colony transmission is prevented by strong social immunity exhibited by social insect societies [2, 3]. It is not clear how such complex examples of host manipulation arose. To address this, we performed a broad-scale phylogenetic reconstruction of the order Hypocreales, to which the zombie-ant fungi, Ophiocordyceps, belong. In order to understand the patterns of host association and host switching along the evolution of Ophiocordyceps, we performed ancestral character state reconstruction analysis. We found that zombie-ant fungi likely arose from an ancestor that infected beetle larvae residing in soil or decaying wood, similar to extant beetle-infecting Ophiocordyceps species. Surprisingly, the jump led to an extensive species radiation observed after the development of behavioral manipulation. We suggest that the jump from solitary beetle larva to ants within a colony exposed the fungus to the robust social immunity of ant societies.
Topics: Animals; Ants; Biological Evolution; Coleoptera; Host-Parasite Interactions; Host-Pathogen Interactions; Hypocreales; Phylogeny; Species Specificity
PubMed: 31668622
DOI: 10.1016/j.cub.2019.09.004 -
Scientific Reports Jul 2020Nature features a plethora of extraordinary photonic architectures that have been optimized through natural evolution in order to more efficiently reflect, absorb or...
Nature features a plethora of extraordinary photonic architectures that have been optimized through natural evolution in order to more efficiently reflect, absorb or scatter light. While numerical optimization is increasingly and successfully used in photonics, it has yet to replicate any of these complex naturally occurring structures. Using evolutionary algorithms inspired by natural evolution and performing particular optimizations (maximize reflection for a given wavelength, for a broad range of wavelength or maximize the scattering of light), we have retrieved the most stereotypical natural photonic structures. Whether those structures are Bragg mirrors, chirped dielectric mirrors or the gratings on top of Morpho butterfly wings, our results indicate how such regular structures might have spontaneously emerged in nature and to which precise optical or fabrication constraints they respond. Comparing algorithms show that recombination between individuals, inspired by sexual reproduction, confers a clear advantage that can be linked to the fact that photonic structures are fundamentally modular: each part of the structure has a role which can be understood almost independently from the rest. Such an in silico evolution also suggests original and elegant solutions to practical problems, as illustrated by the design of counter-intuitive anti-reflective coatings for solar cells.
Topics: Algorithms; Animals; Biological Evolution; Butterflies; Coleoptera; Computational Biology; Computer Simulation; Nanostructures; Photons; Reproduction; Wings, Animal
PubMed: 32694514
DOI: 10.1038/s41598-020-68719-3 -
Insect Science Jun 2020Many insects feed on a low-nitrogen diet, and the origin of their nitrogen supply is poorly understood. It has been hypothesized that some insects rely on... (Review)
Review
Many insects feed on a low-nitrogen diet, and the origin of their nitrogen supply is poorly understood. It has been hypothesized that some insects rely on nitrogen-fixing bacteria (diazotrophs) to supplement their diets. Nitrogen fixation by diazotrophs has been extensively studied and convincingly demonstrated in termites, while evidence for the occurrence and role of nitrogen fixation in the diet of other insects is less conclusive. Here, we summarize the methods to detect nitrogen fixation in insects and review the available evidence for its occurrence (focusing on insects other than termites). We distinguish between three aspects of nitrogen fixation investigations: (i) detecting the presence of potential diazotrophs; (ii) detecting the activity of the nitrogen-fixing enzyme; and (iii) detecting the assimilation of fixed nitrogen into the insect tissues. We show that although evidence from investigations of the first aspect reveals ample opportunities for interactions with potential diazotrophs in a variety of insects, demonstrations of actual biological nitrogen fixation and the assimilation of fixed nitrogen are restricted to very few insect groups, including wood-feeding beetles, fruit flies, leafcutter ants, and a wood wasp. We then discuss potential implications for the insect's fitness and for the ecosystem as a whole. We suggest that combining these multiple approaches is crucial for the study of nitrogen fixation in insects, and argue that further demonstrations are desperately needed in order to determine the relative importance of diazotrophs for insect diet and fitness, as well as to evaluate their overall impact on the ecosystem.
Topics: Animals; Bacteria; Coleoptera; Diet; Diptera; Ecosystem; Gastrointestinal Microbiome; Hemiptera; Insecta; Isoptera; Nitrogen; Nitrogen Fixation
PubMed: 31207108
DOI: 10.1111/1744-7917.12697 -
The Journal of Experimental Biology Dec 2019Nature's nanostructures can bring about vivid and iridescent colours seen in many insects, notably in beetles and butterflies. While the intense structural colours can...
Nature's nanostructures can bring about vivid and iridescent colours seen in many insects, notably in beetles and butterflies. While the intense structural colours can be advantageous for display purposes, they may also be appealing to predators and therefore constitute an evolutionary disadvantage. Animals often employ absorption and scattering in order to reduce the directionality of the reflected light and thereby enhance their camouflage. Here, we investigated the monkey beetle using microspectrophotometry, electron microscopy, fluorimetry and optical modelling. We show that the dull green dorsal colour comes from the nanostructured scales on the elytra. The nanostructure consists of a multi-layered photonic structure covered by a filamentous layer. The filamentous layer acts as a spatial diffuser of the specular reflection from the multilayer and suppresses the iridescence. This combination leads to a colour-stable and angle-independent green reflection that probably enhances the camouflage of the beetles in their natural habitat.
Topics: Animals; Coleoptera; Color; Female; Fluorometry; Male; Microscopy, Electron, Scanning; Microspectrophotometry; Models, Biological
PubMed: 31767735
DOI: 10.1242/jeb.213306 -
Molecular Ecology Resources Aug 2021The hyperdiverse order Coleoptera comprises a staggering ~25% of known species on Earth. Despite recent breakthroughs in next generation sequencing, there remains a...
The hyperdiverse order Coleoptera comprises a staggering ~25% of known species on Earth. Despite recent breakthroughs in next generation sequencing, there remains a limited representation of beetle diversity in assembled genomes. Most notably, the ground beetle family Carabidae, comprising more than 40,000 described species, has not been studied in a comparative genomics framework using whole genome data. Here we generate a high-quality genome assembly for Nebria riversi, to examine sources of novelty in the genome evolution of beetles, as well as genetic changes associated with specialization to high-elevation alpine habitats. In particular, this genome resource provides a foundation for expanding comparative molecular research into mechanisms of insect cold adaptation. Comparison to other beetles shows a strong signature of genome compaction, with N. riversi possessing a relatively small genome (~147 Mb) compared to other beetles, with associated reductions in repeat element content and intron length. Small genome size is not, however, associated with fewer protein-coding genes, and an analysis of gene family diversity shows significant expansions of genes associated with cellular membranes and membrane transport, as well as protein phosphorylation and muscle filament structure. Finally, our genomic analyses show that these high-elevation beetles have endosymbiotic Spiroplasma, with several metabolic pathways (e.g., propanoate biosynthesis) that might complement N. riversi, although its role as a beneficial symbiont or as a reproductive parasite remains equivocal.
Topics: Adaptation, Physiological; Animals; Cold Temperature; Coleoptera; Evolution, Molecular; Genome Size; Genome, Insect; Genomics; High-Throughput Nucleotide Sequencing; Phylogeny
PubMed: 33938156
DOI: 10.1111/1755-0998.13409 -
Insect Biochemistry and Molecular... Nov 2019Insects employ neuropeptides to regulate their growth & development, behaviour, metabolism and their internal milieu. At least 50 neuropeptides are known to date, with... (Comparative Study)
Comparative Study
Insects employ neuropeptides to regulate their growth & development, behaviour, metabolism and their internal milieu. At least 50 neuropeptides are known to date, with some ancestral to the insects and others more specific to particular taxa. In order to understand the evolution and essentiality of neuropeptides, we data mined publicly available high quality genomic or transcriptomic data for 31 species of the largest insect Order, the Coleoptera, chosen to represent the superfamilies' of the Adephaga and Polyphaga. The resulting neuropeptide distributions were compared against the habitats, lifestyle and other parameters. Around half of the neuropeptide families were represented across the Coleoptera, suggesting essentiality or at least continuing utility. However, the remaining families showed patterns of loss that did not correlate with any obvious life history parameter, suggesting that these neuropeptides are no longer required for the Coleopteran lifestyle. This may perhaps indicate a decreasing reliance on neuropeptide signaling in insects.
Topics: Amino Acid Sequence; Animals; Biological Evolution; Coleoptera; Feeding Behavior; Genome, Insect; Molting; Neuropeptides; Reproduction; Transcriptome; Water-Electrolyte Balance
PubMed: 31470084
DOI: 10.1016/j.ibmb.2019.103227 -
Microscopy Research and Technique May 2021Melolonthinae are the largest subfamily of Scarabaeidae, considered as serious pests for their larvae attacking plant roots and tubers. The edaphic larvae are difficult...
Melolonthinae are the largest subfamily of Scarabaeidae, considered as serious pests for their larvae attacking plant roots and tubers. The edaphic larvae are difficult to be identified because the study on larval taxonomy is far from satisfactory. In this study, multivoltine white grubs Melolontha incana (Motschulsky, 1853) were investigated using light and scanning electron microscopy, in order to provide more morphological characters for the pest identification. The white grubs are atypical for the epipharynx bearing 14 heli arranged in two rows; the mandible is furnished with a patch of minute granules; the maxilla is equipped with 18 acute stridulatory teeth arranged in line; each femur and tibiotarsus is furnished ventrally with a cluster of fossorial setae. The morphological comparisons with the other melolonthine species were provided. The adaptative relationship between the morphological feature and the multivoltine life history were briefly discussed.
Topics: Animals; Coleoptera; Larva
PubMed: 33231351
DOI: 10.1002/jemt.23653 -
Journal of Economic Entomology Oct 2020Euwallacea fornicatus (Eichhoff), the polyphagous shot hole borer (PSHB), is an ambrosia beetle infesting avocado Persea americana Mill. limbs in North America and...
Euwallacea fornicatus (Eichhoff), the polyphagous shot hole borer (PSHB), is an ambrosia beetle infesting avocado Persea americana Mill. limbs in North America and Israel. We conducted field experiments with sticky traps in avocado orchards to develop push-pull semiochemical methods of managing PSHB. Traps baited with 10-fold increasing doses (0.01 to 100× or 1.26 µg to 12.6 mg/d) of attractant quercivorol were previously shown to increasingly capture female PSHB (males flightless). We converted trap catch of this relationship to a standardized effective attraction radius (EAR) that predicts capture power of baited-traps regardless of insect flight density. Earlier, piperitone and verbenone were shown to strongly inhibit attraction of PSHB to quercivorol-traps. We tested increasing numbers of 1× piperitone dispensers at 0.75-m distance surrounding a quercivorol-trap and found PSHB catch to decline exponentially. Increasing decadic doses (0.01 to 10×) of either verbenone or piperitone released at 1× quercivorol-traps caused a sigmoidal first-order kinetic-decay in catch. Verbenone (1×) placed at increasing distances (0, 0.25, 0.5, 1, and 2 m) from a 1× quercivorol-trap became increasingly ineffective in reducing catch of PSHB. We found no evidence that ethanol released from 7.5 to 480 mg/d affected attraction of PSHB, but Scobicia chevrieri (Villa and Villa) (Coleoptera: Bostrichidae) was increasingly attracted. Due to their relatively short-range (<0.5 m) inhibition of attractive sources, piperitone, and verbenone dispensers should be placed on avocado trunks where PSHB aggregations occur before the flight season.
Topics: Ambrosia; Animals; Coleoptera; Female; Insect Control; Israel; Male; Monoterpenes; North America; Pheromones; Weevils
PubMed: 32596735
DOI: 10.1093/jee/toaa127