Journal of Insect Science最新文献

The subfamily Molytinae (Coleoptera: Curculionidae), being the second largest group within the family Curculionidae, exhibits a diverse range of hosts and poses a serious threat to agricultural and forestry industries. We used 1,290 cytochrome c oxidase subunit I (COI) barcodes to assess the efficiency of COI barcodes in species differentiation and uncover cryptic species diversity within weevils of Molytinae. The average Kimura 2-parameter distances within species, genus, and subfamily were 2.90%, 11.0%, and 22.26%, respectively, indicating significant genetic differentiation at both levels. Moreover, there exists a considerable degree of overlap between intraspecific (0%-27.50%) and interspecific genetic distances (GDs; 0%-39.30%). The application of Automatic barcode gap discovery, Assemble Species by Automatic Partitioning, Barcode Index Number, Poisson Tree Processes (PTP), Bayesian Poisson Tree Processes (bPTP), and jMOTU resulted in the identification of 279, 275, 494, 322, 320, and 279 molecular operational taxonomic units, respectively. The integration of 6 methods successfully delimited species of Molytinae in 86.6% of all examined morphospecies, surpassing a threshold value of 3% GD (73.0%). A total of 28 morphospecies exhibiting significant intraspecific divergences were assigned to multiple MOTUs, respectively, suggesting the presence of cryptic diversity or population divergence. The identification of cryptic species within certain morphological species in this study necessitates further investigation through comprehensive taxonomic practices in the future.

Metacephalus Delong and Martinson, 1973 includes leafhopper species from Argentina, Bolivia, Brazil, Colombia, Ecuador (new record), Guyana, French Guiana (new record), Panama, Peru, and Venezuela. In the present revisionary study, we describe seven new species of Metacephalus, propose one species synonymy (M. cinctus as junior synonym of M. facetus), and provide new country records for species, considerably expanding knowledge about species distributions. The study also provides redescriptions and photographs of diagnostic characters for 12 previously described valid species and an identification key to all 21 species of Metacephalus. Molecular phylogenies of Metacephalus species are hypothesized based on maximum likelihood and Bayesian inference analyses of 1,387 bp of mitochondrial Cytochrome Oxidase I and 16S rDNA and nuclear histone H3. Results of the molecular phylogeny generated herein provided a base for understanding character homologies when presenting morphological diagnoses of Metacephalus species and exposed a high level of convergent characters in color pattern and male genitalia morphology usually used in morphological taxonomy of this group of leafhoppers.

Recent studies on oestroidean Diptera (Brachycera) are providing a comprehensive and nuanced understanding of the evolutionary history of this remarkably diverse clade of holometabolous insects. The Oestroidea, which includes formidable pests such as various blowflies, botflies, and flesh flies that infest livestock, pets and humans, are mostly composed of beneficial species that act as scavengers or parasitoids on various pest insects. In our research, we used genomic methods to elucidate the phylogenetic position of Nesodexia corsicana Villeneuve, 1911 (Diptera: Calliphoridae), a mysterious oestroid species endemic to Corsica and characterized by distinctive morphological features that have puzzled taxonomists for years. Contrary to initial hypotheses, our results place Nesodexia Villeneuve, 1911 within the Calliphoridae subfamily Rhinophorinae, a small lineage of terrestrial isopod parasitoids. Through detailed morphological analysis of adults of both sexes and eggs, we uncovered significant insights consistent with our phylogenomic reconstruction. The unique morphological features of the species, coupled with its restricted and fragmented habitat, highlight its potential conservation importance. We delineated the area of occupancy for N. corsicana and assessed its "threatened" category using specific IUCN Red List criteria. In addition, we mapped the available habitat within its range and determined potential key biodiversity areas (KBA) triggered by N. corsicana. New potential KBAs are only partially covered by the Corsican Regional Park. Finally, we mapped the distribution of habitats on the island to assess the potential distribution of the species beyond its currently known geographic range.

The date palm (Phoenix dactylifera L.) (Arecales: Arecaceae) is the most economically important crop in Oman with an annual production of >360,000 tons of fruit. The Dubas bug (Ommatissus lybicus de Bergevin) (Hemiptera: Tropiduchidae) is one of the major pests of date palms, causing up to a 50% reduction in fruit production. Across the course of 2 seasons, a variety of arthropod predators living in the date palm canopy were investigated for possible biological control of Dubas bugs, given the growing interest in nonchemical insect pest control in integrated pest management. We collected ~6,900 arthropod predators directly from date palm fronds from 60 Omani date palm plantations and tested them for Dubas bug predation using PCR-based molecular gut content analysis. We determined that ≥56 species of arthropod predators feed on the Dubas bug. We found that predatory mites, ants, and the entire predator community combined showed a positive correlation between predation detection frequency and increasing Dubas bug density. Additionally, there was a significant impact of season on gut content positives, with the spring season having a significantly higher percentage of predators testing positive for Dubas bug, suggesting this season could be the most successful time to target conservation biological control programs utilizing a diverse suite of predators.

The study aims to assess the impact of oven-drying and decontamination on crude protein concentration and in vitro crude protein digestibility of yellow mealworms. Two kilograms of 12-wk-old mealworm larvae were subjected to freezing prior to the drying process. Approximately 1.5 kg of mealworm larvae were divided into 3 groups and exposed to oven-drying at temperatures of 50 °C for 36 h, 60 °C, and 70 °C for 24 h each. At intervals of 2 h, sets of 3 replicates were withdrawn to record water loss. Consistent weight stabilization was observed at 36 h for 50 °C (T50), 18 h for 60 °C (T60), and 14 h for 70 °C (T70). The remaining 0.5 kg of mealworm larvae was divided and dried under treatments T50, T60, and T70. Each treatment was then split into 2 portions, with one portion subjected to 90 °C for 15 min (denoted as T50-90, T60-90, T70-90) to eliminate microbial contamination. The 6 treatments were then used to determine concentrations of dry matter, crude ash, crude protein, pre-caecal protein digestibility, and dry matter residues after neutral detergent fiber, acid detergent fiber, and acid detergent lignin treatments. No interaction was observed between drying and decontamination treatments (P > 0.17). Pre-caecal crude protein digestibility increased with decreasing temperature (T50: 58% crude protein; T60: 51% crude protein; T70: 50% crude protein). Therefore, lower temperatures for longer times preserve crude protein digestibility. These findings are crucial for understanding how drying temperature and time impact protein bioavailability.

CRISPR/Cas9 manipulations are possible in many insects and ever expanding. Nonetheless, success in one species and techniques developed for it are not necessarily applicable to other species. As such, the development and expansion of CRISPR-based (clustered regularly interspaced short palindromic repeats) genome-editing tools and methodologies are dependent upon direct experimentation. One useful technique is Cas9-dependent homologous recombination, which is a critical tool for studying gene function but also for developing pest related applications like gene drive. Here, we report our attempts to induce Cas9 homology directed repair (HDR) and subsequent gene drive in Tribolium castaneum (Herbst; Insecta: Coleoptera: Tenebrionidae). Utilizing constructs containing 1 or 2 target gRNAs in combination with Cas9 under 2 different promoters and corresponding homology arms, we found a high incidence of CRISPR/Cas9 induced mutations but no evidence of homologous recombination. Even though the generated constructs provide new resources for CRISPR/Cas9 modification of the Tribolium genome, our results suggest that additional modifications and increased sample sizes will be necessary to increase the potential and detection for HDR of the Tribolium genome.

Pennycress (Thlaspi arvense L.) is an annual plant in temperate regions that often grows as a weed. Pennycress is being domesticated as a new winter cover crop and oilseed crop for incorporation in the Midwest United States corn-soybean rotation, where it could offer economic and environmental benefits. While pennycress is gaining attention as a promising new crop, there remains a significant gap in understanding its interaction with insect communities and agroecosystems. This review compiles available information on insect herbivores (potential pests) and beneficial insects associated with pennycress growing in the wild (natural areas) or as a weed in agricultural areas. The limited knowledge on the response of pennycress to stressors (defoliation, stem injury and stand loss) similar to injury that could be caused by insects is also compiled here. By shedding light on the insects associated with pennycress and how pennycress might respond to injury from insect pests, this review sets the stage for further research and development of integrated pest management programs for insect pests of this new crop.

Rust fungi (Pucciniales) are plant pathogens that can cause devastating yield losses to economically important crops and threaten native plants with extinction. Rusts are usually controlled with fungicides when rust-resistant plant varieties are unavailable. However, natural enemies may offer an alternative to chemicals by acting as biological controls. The larvae of Mycodiplosis Rübsaamen (49 spp.) feed on the spores of rusts and powdery mildew fungi and have been suggested as a potential biocontrol candidate for disease-causing rusts. However, little is known about the phylogenetic relationships, biogeography, and host range of this genus. We screened 5,665 rust specimens from fungarium specimens and field collections and recovered a total of 363 larvae on 315 rust specimens from 17 countries. Three mitochondrial and 2 nuclear loci were amplified and sequenced for the phylogenetic reconstruction of 129 individuals. We recovered 12 clades, of which 12 and 10 were supported with maximum likelihood and Bayesian inference, respectively. Of the 12 clades, 7 comprised species from multiple continents and climatic regions, and 5 comprised species from a single region. Individuals forming clades were collected from 2 to 18 rust species, suggesting that Mycodiplosis species have a broad host range. In total, Mycodiplosis larvae were identified on 44 different rust species collected from 18 plant families. Future studies should focus on expanding field sampling efforts, including data from additional gene regions, and incorporating morphological data to further elucidate species diversity and distribution patterns.

Advances in molecular ecology can overcome many challenges in understanding host-parasitoid interactions. Genetic characterization of the key-players in systems helps to confirm species and identify trophic linkages essential for ecological service delivery by biological control agents; however, relatively few agroecosystems have been explored using this approach. Pecan production consists of a large tree perennial system containing an assortment of seasonal pests and natural enemies. As a first step to characterizing host-parasitoid associations in pecan food webs, we focus on aphid species and their parasitoids. Based on DNA barcoding of field-collected and reared specimens, we confirmed the presence of 3 species of aphid, one family of primary parasitoids, and 5 species of hyperparasitoids. By applying metabarcoding to field-collected aphid mummies, we were able to identify multiple species within each aphid mummy to unravel a complex food web of 3 aphids, 2 primary parasitoids, and upward of 8 hyperparasitoid species. The results of this study demonstrate that multiple hyperparasitoid species attack a single primary parasitoid of pecan aphids, which may have negative consequences for successful aphid biological control. Although further research is needed on a broader spatial scale, our results suggest multiple species exist in this system and may suggest a complex set of interactions between parasitoids, hyperparasitoids, and the 3 aphid species. This was the first time that many of these species have been characterized and demonstrates the application of novel approaches to analyze the aphid-parasitoid food webs in pecans and other tree crop systems.

Insects live in a wide range of thermal environments and have evolved species- and location-specific physiological processes for survival in hot and cold extremes. Thermally driven dormancy strategies, development rates and thresholds are important for synchronizing cohorts within a population and to local climates and often vary among populations within a species. Mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is a widely distributed forest insect native to North America with clinal genetic differentiation in thermally dependent traits. MPB development occurs in Pinus phloem beneath the bark, and its cryptic habitat makes experimentation difficult, particularly for the adult stage. We describe a novel method for modeling MPB adult development following pupation and terminating in emergence from a brood tree. We focus on an Arizona (southern) MPB population with previously described preadult development rates. Field-observed tree attack, adult emergence, and phloem temperature data are combined in a parameterized cohort model and candidate rate curves are evaluated to describe adult emergence timing. Model competition indicates that the Brière rate curve provided the best fit to field data and performed well under cross-validation. Results confirm that the development of Arizona MPB adults is slower than the previously described development rate of more northern Utah adults. Using the estimated adult rate curve in a scenario of increasing mean temperatures, we show that the timing of second-generation adult emergence in the same year would result in cold-intolerant lifestages during winter, limiting the success of bivoltine populations.