ResearchPad - entomology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Full-length transcriptome and targeted metabolome analyses provide insights into defense mechanisms of <i>Malus sieversii</i> against <i>Agrilus mali</i>]]> https://www.researchpad.co/article/elastic_article_8337 Malus sieversii is the wild progenitor for many cultivars of domesticated apple and an important germplasm resource for breeding. However, this valuable species faces a significant threat in the areas north of the Tianshan Mountains in China, by the invasion of Agrilus mali, a destructive pest of apple trees belonging to the family Buprestidae. Our preliminary study has has shown that there may be resistance to this insect in M. sieversii plants in the field, but the corresponding molecular mechanisms remain unclear. In this study, we compared the response of insect-resistant and insect-susceptible plants of M. sieversii to insect feeding using full-length transcriptome and targeted metabolome. 112,103 non-chimeric full-length reads (FLNC) totaling 10.52 Gb of data were generating with Pacific Biosciences SingleMolecule, Real-Time (PacBio SMRT) sequencing. A total of 130.06 Gb data of long reads were acquired with an Illumina HiSeq. Function annotation indicated that the different expressed genes (DEGs) were mainly involved in signal transduction pathway of plant hormones and in the synthesis of compounds such as terpenes, quinones, flavonoids, and jasmonic acid. Through targeted metabolome analysis resistant strains showed higher levels of trans-cinnamic acid, caffeine and ferulic acid after pest infestation. This study helps to decipher the transcriptional changes and related signaling paths in M. sieversii after an insect feeding, which lays a foundation for further research on molecular mechanisms of insect resistance in apples.

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<![CDATA[A new species of <i>Cenopalpus</i> Pritchard &amp; Baker (Acari: Tenuipalpidae) from Japan, with ontogeny of chaetotaxy and a key to the world species]]> https://www.researchpad.co/article/N8179289f-7933-4eb0-92ba-b50426ec4032 A new species of flat mite, Cenopalpus umbellatus sp. nov. (Acari: Trombidiformes: Tenuipalpidae) is described and illustrated based on females, males, deutonymphs, protonymphs and larvae. The morphological ontogeny in idiosomal and leg chaetotaxy is briefly described for all stages. Mite specimens were collected from the leaves of Rhaphiolepis indica var. umbellata Makino (Rosaceae), an evergreen shrub native to Japan. An identification key to the world species of Cenopalpus is also provided.

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<![CDATA[Ooctonus vulgatus (Hymenoptera, Mymaridae), a potential biocontrol agent to reduce populations of Philaenus spumarius (Hemiptera, Aphrophoridae) the main vector of Xylella fastidiosa in Europe]]> https://www.researchpad.co/article/N503c34c3-73c7-4316-aa36-d8ecad427c59

As a vector of Xylella fastidiosa (Wells, 1987) in Europe, the meadow spittlebug Philaenus spumarius (Linnaeus, 1758) (Hemiptera, Aphrophoridae) is a species of major concern. Therefore, tools and agents to control this ubiquitous insect that develops and feeds on hundreds of plant species are wanted. We conducted a field survey of P. spumarius eggs in Corsica and provide a first report of Ooctonus vulgatus Haliday, 1833 (Hymenoptera, Mymaridae) as a potential biocontrol agent of P. spumarius in Europe. To allow species identification, we summarized the main characters distinguishing O. vulgatus from other European species of Ooctonus and generated COI DNA barcodes. Parasitism rates were variable in the four localities included in the survey but could reach 69% (for an average number of eggs that hatched per locality of 109). Based on the geographic occurrences of O. vulgatus obtained from the literature, we calibrated an ecological niche model to assess its potential distribution in the Holarctic. Obviously, several questions need to be addressed to determine whether O. vulgatus could become an effective biocontrol agent of P. spumarius in Europe. So far, O. vulgatus has been reared only from P. spumarius eggs, but its exact host-range should be evaluated to ensure efficiency and avoid non-target effect. The top-down impact of the parasitoid on vector populations should also be assessed on large data sets. Finally, the feasibility of mass rearing should be tested. We hope this report serves as a starting point to initiate research on this parasitoid wasp to assess whether it could contribute to reduce the spread and impact of X. fastidiosa in Europe.

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<![CDATA[Impact of confinement in vehicle trunks on decomposition and entomological colonization of carcasses]]> https://www.researchpad.co/article/Nffbdbe54-85a9-48b9-9e05-57433aec6303

In order to investigate the impact of confinement in a car trunk on decomposition and insect colonization of carcasses, three freshly killed pig (Sus scrofa domesticus Erxleben) carcasses were placed individually in the trunks of older model cars and deployed in a forested area in the southwestern region of British Columbia, Canada, together with three freshly killed carcasses which were exposed in insect-accessible protective cages in the same forest. Decomposition rate and insect colonization of all carcasses were examined twice a week for four weeks. The exposed carcasses were colonized immediately by Calliphora latifrons Hough and Calliphora vomitoria (L.) followed by Lucilia illustris (Meigen), Phormia regina (Meigen) and Protophormia terraenovae (R.-D.) (Diptera: Calliphoridae). There was a delay of three to six days before the confined carcasses were colonized, first by P. regina, followed by Pr. terraenovae. These species represented the vast majority of blow fly species on the confined carcasses. Despite the delay in colonization, decomposition progressed much more rapidly in two of the confined carcasses in comparison with the exposed carcasses due to the greatly increased temperatures inside the vehicles, with the complete skeletonization of two of the confined carcasses ocurring between nine and 13 days after death. One confined carcass was an anomaly, attracting much fewer insects, supporting fewer larval calliphorids and decomposing much more slowly than other carcasses, despite similarly increased temperatures. It was later discovered that the vehicle in which this carcass was confined had a solid metal fire wall between the passenger area and the trunk, which served to reduce insect access and release of odors. These data may be extremely valuable when analyzing cadavers found inside vehicle trunks.

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<![CDATA[Validation of Reference Genes for Gene Expression Studies in Aphis glycines (Hemiptera: Aphididae)]]> https://www.researchpad.co/article/N9fe1cf7f-c3ec-4f02-b3b1-84bdd4b1e830

Quantitative real-time polymerase chain reaction (qRT-PCR) is a common and robust tool for accurate quantification of mRNA transcripts. To normalize results, a housekeeping gene ([HKG], reference gene or endogenous control gene) is mandatory. Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a significant soybean, Glycine max (L.) Merr., pest, yet gene expression and functional genomics studies are hindered by a lack of stable HKGs. We evaluated seven potential HKGs (SDFS, succinate dehydrogenase flavoprotein subunit; EF1a, elongation factor-1α; HEL, helicase; GAPDH, glyceraldehyde-3 phosphate dehydrogenase; RPS9, ribosomal protein S9; TBP, TATA-box binding protein; and UBQ, ubiquitin-conjugating protein) to determine the most efficient HKGs that have stable expression among tissues, developmental stages, and aphids fed on susceptible and host plant–resistant soybean. HKG stability was determined using GeNorm and NormFinder. Results from three different experimental conditions revealed high stability of TBP compared with the other HKGs profiled across the samples assayed. RPS9 showed stable expression among aphids on susceptible and resistant plants, whereas EF1a showed stable expression in tissues and developmental stages. Therefore, we recommend the TBP as a suitable HKG for efficient normalization among treatments, tissues, and developmental stages of A. glycines. In addition, RPS9 may be used for host-plant resistance experiments and EF1a could be considered for testing differential expression across tissues or developmental stages. These results will enable a more accurate and reliable normalization of qRT-PCR data in A. glycines.

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<![CDATA[Rapid Identification of the Mediterranean Fruit Fly (Diptera: Tephritidae) by Loop-Mediated Isothermal Amplification]]> https://www.researchpad.co/article/Nebe7754d-af4c-453d-8ba8-eac41e4e1c88

Abstract

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), ranks as one of the world’s most destructive agricultural pests. This pest is also widespread and highly invasive; thus, it is a high priority for pest detection and quarantine programs. Although Mediterranean fruit fly adult and third-instar larvae can usually be identified and distinguished from other species by morphological keys, it is often difficult or impossible to identify or distinguish this species from other tephritids by using material from other stages of development. In such situations, use of a molecular technique known as loop-mediated isothermal amplification (LAMP) would be valuable as a rapid and robust alternative species diagnostic tool. This method uses isothermal conditions and requires only relatively inexpensive equipment. In this study we have developed a simple and rapid procedure that combines a Chelex-based DNA extraction procedure with LAMP to rapidly detect the presence of Mediterranean fruit fly DNA and discriminate it from other species, by using material from different stages of development. Amounts of DNA as little as that recovered from a single egg were shown to be adequate for the analysis, and LAMP itself required only 45 min to complete.

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<![CDATA[Susceptibility of the Lesser Mealworm, Alphitobius diaperinus (Coleoptera: Tenebrionidae), From Broiler Farms of Southern Brazil to Insecticides]]> https://www.researchpad.co/article/N7aac3ac0-b971-42ab-bd71-e70df5b5b625

Abstract

The lesser mealworm, Alphitobius diaperinus (Panzer, 1797) (Coleoptera: Tenebrionidae), is considered the primary insect pest in broiler farms in Brazil. In this study, we characterized the susceptibility of A. diaperinus populations from broiler farms of southern Brazil to cypermethrin and chlorpyrifos. Larvae and adults of A. diaperinus were exposed to these technical insecticides diluted in acetone in residual bioassays. A geographic variation in the susceptibility of larvae and adults of A. diaperinus to both insecticides was detected. The larval LC50 for cypermethrin ranged from 0.43 to 7.33 µg a.i./cm2. Two populations from Santa Catarina state presented higher resistance ratios of 13.6- and 17-fold. When adults were exposed to cypermethrin, the LC50 ranged from 0.46 to 4.93 µg a.i./cm2, with population SC-3 from Santa Catarina having lower susceptibility (resistance ratio of 10.7-fold). When exposed to chlorpyrifos, A. diaperinus larvae present LC50 values ranging from 0.21 to 4.30 µg a.i./cm2. Larvae from Paraná and Santa Catarina (SC-1 population) presented the highest resistance ratios, ranging from 10- to 20-fold. In adults, the LC50 of chlorpyrifos ranged from 0.17 to 5.30 µg a.i./cm2, showing a maximum resistance ratio of 31-fold in a population from Paraná state. Based on LC99 values, candidate diagnostic concentrations of 15 and 12 µg a.i./cm2 of cypermethrin and chlorpyrifos, respectively, were also estimated for the resistance monitoring of A. diaperinus in Brazil. The implications of these results in Insect Resistance Management are discussed.

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<![CDATA[Lesser Mealworm (Coleoptera: Tenebrionidae) Emergence After Mechanical Incorporation of Poultry Litter into Field Soils]]> https://www.researchpad.co/article/Ndee1d429-0e72-4a6e-92d5-da2b8349afc6

Abstract

Lesser mealworm, Alphitobius diaperinus (Panzer), emergence from North Carolina field soils was evaluated in a controlled experiment simulating land application of turkey litter and again in field studies. Adult lesser mealworms were buried in central North Carolina Cecil red clay at depths of 0, 8, 15, 23, and 30 cm and the beetles emerging from the soil counted 1, 3, 7, 10, 13, 17, 21, 24, and 28 d after burial. Beetles emerged from all depths and differences among depths were not significant. Beetles survived at least 28 d buried in the soil at depths ≤30 cm. In seasonal field studies, lesser mealworm emergence from clay soil with poultry litter incorporated by disk, mulch and plow was compared with emergence from plots with no incorporation. Incorporation significantly reduced beetle emergence when poultry litter containing large numbers of beetles was applied to clay field soils during the summer (F = 3.45; df = 3, 143; P = 0.018). Although mechanical incorporation of poultry litter reduced beetle emergence relative to the control, greatest reductions were seen in plowed treatments. Beetle activity was reduced after land application of litter during colder months. Generally, lesser mealworm emergence decreased with time and few beetles emerged from the soil 28 d after litter was applied. Similarly, mechanical incorporation of poultry litter into sandy soils reduced beetle emergence (F = 4.06; df = 3, 143; P < 0.008). In sandy soils typical of eastern North Carolina, disk and plow treatments significantly reduced beetle emergence compared with control.

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<![CDATA[ Application of the LAMP Assay as a Diagnostic Technique for Rapid Identification of Thrips tabaci (Thysanoptera: Thripidae) ]]> https://www.researchpad.co/article/Nb1ebdb7a-349d-42d3-af88-f67195433f73

Abstract

Rapid and accurate identification of potentially invasive taxa that may cause high economic losses or environmental damage is of critical importance. The onion thrips, Thrips tabaci Lindeman, ranks as one of the world’s most destructive agricultural pests and commonly found in imported agricultural products and field samples, but is prone to undetected transport because of its minute size as well as cryptic behavior. Although traditional taxonomic methods are pretty useful in straightforward assignment of specimens to the genus Thrips , identification in the species level is much more difficult and requires expertise, knowledge, and experience. Furthermore, it is often difficult or impossible to identify or distinguish this species from other thrips by using material from other stages of development. Based on the foregoings, use of a molecular technique known as loop-mediated isothermal amplification (LAMP) as a rapid and robust alternative species diagnostic tool would be valuable. In this study, a relatively quick and simple method was used to detect the presence of onion thrips DNA rapidly and discriminate it from other species, by using material from different stages of development. Not only LAMP itself required less than 1 h to complete but also amounts of DNA as little as that recovered from a single specimen were adequate for the detection. Another advantage of this identification system is that nonspecialists will be able to make faster and cheaper identifications.

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<![CDATA[Mixed effects of ecological intensification on natural pest control providers: a short-term study for biotic homogenization in winter wheat fields]]> https://www.researchpad.co/article/Nfe327807-304e-4591-9fac-22e6bc47b7f6

Agricultural intensification is one of the major drivers of biotic homogenization and has multiple levels ranging from within-field management intensity to landscape-scale simplification. The enhancement of invertebrate assemblages by establishing new, semi-natural habitats, such as set-aside fields can improve biological pest control in adjacent crops, and mitigate the adverse effect of biotic homogenization. In this study we aimed to examine the effects of ecological intensification in winter wheat fields in Hungary. We tested how pests and their natural enemies were affected at different spatial scales by landscape composition (proportion of semi-natural habitats in the surrounding matrix), configuration (presence of adjacent set-aside fields), and local field management practices, such as fertilizer (NPK) applications without applying insecticides. We demonstrated that at the local scale, decreased fertilizer usage had no direct effect either on pests or their natural enemies. Higher landscape complexity and adjacent semi-natural habitats seem to be the major drivers of decreasing aphid abundance, suggesting that these enhanced the predatory insect assemblages. Additionally, the high yield in plots with no adjacent set-aside fields suggests that intensive management can compensate for the lower yields on the extensive plots. Our results demonstrated that although complexity at the landscape scale was crucial for maintaining invertebrate assemblages, divergence in their response to pests and pathogens could also be explained by different dispersal abilities. Although the landscape attributes acted as dispersal filters in the organization of pest and pathogen assemblages in croplands, the presence of set-aside fields negatively influenced aphid abundance due to their between-field isolation effect.

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<![CDATA[Evaluation of δ15N analysis to trace the origin of Diaphorina citri (Hemiptera: Liviidae) to citrus orchard fertilization management]]> https://www.researchpad.co/article/N9d6c8da1-5d90-4a77-b04e-0cf6afddf2a2

We investigated the variability of nitrogen stable isotope ratios 15N/14N (expressed as δ15N) on citrus orchards with different fertilization management practices (organic versus conventional) and its correlation with the δ15N values of the key citrus pest Diaphorina citri Kuwayama (Hemiptera: Liviidae) feeding on such plant material. Tracing the origin of this pest in open field is crucial since the insect is a vector of the incurable and devastating citrus disease known as Huanglongbing. We hypothesized that the origin (natal tree) of the pest may be deduced by correlating the δ15N values obtained from the young citrus leaves and from adults of D. citri raised on them. First, laboratory experiments were performed to understand the acquisition and incorportation of the δ15N values by D. citri. Second, we confirmed the positive correlation between the δ15N values of the young citrus leaves and D. citri. Finally, field sampling was carried out in 21 citrus orchards from Southern California to study the variability on the δ15N values on organic and conventional commercial citrus orchards. Laboratory results suggest that the analyses of the δ15N values can be regarded as a useful method to trace the origin of the pest. However, the high variability in nitrogen resource used in both fertilization management practices (especially in organic orchards) by growers makes the application of this technique unfeasible to pinpoint the origin of D. citri in the citrus agroecosystem.

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<![CDATA[Evaluation of a Barrier to Inhibit Lesser Mealworm (Coleoptera: Tenebrionidae) and Dermestidae Movement in High-Rise, Caged-Layer Poultry Facilities]]> https://www.researchpad.co/article/Ne442f38f-deaf-4fa7-ba3e-615fcb4e0270

Abstract

An evaluation of a mechanical barrier to prevent movement of adult and larval lesser mealworm, Alphitobius diaperinus (Panzer); larder beetle, Dermestes lardarius L.; and hide beetle, Dermestes maculatus De Geer was conducted in caged-layer poultry facilities in New York and Maine. The barrier, a plastic collar wrapped around building support posts, proved highly effective at preventing movement of adult lesser mealworms. Significantly more lesser mealworm larvae were recovered from cardboard collar beetle traps placed below both washed and unwashed barriers than from traps placed above washed and unwashed barriers. Similarly, significantly more adult Dermestes were recovered from traps placed below washed barriers than from above both washed and unwashed barriers. The level of fly specking on the barrier was found to have no significant impact on the numbers of adult lesser mealworms and adult and larval Dermestes recovered either above or below barriers. Fly specking level did significantly impact the numbers of lesser mealworm larvae recovered above the barrier. Although washed barriers provided the greatest deterrent to adult lesser mealworms, the presence of the barrier, regardless of the level of fly specking, provided a significant deterrent to beetle climbing success. Washed barriers further reduced climbing success by lesser mealworm larvae by 17%, Dermestes adults by 7–28%, and Dermestes larvae by 33–38%. The high level of climbing observed by adult lesser mealworms suggests that the impact of adult beetle movement toward birds should be considered in its importance in building damage, disease transmission, feed infestation, and bird productivity and health. Observations on cost and maintenance of the barrier are discussed.

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<![CDATA[Suppression of Adult Lesser Mealworm (Coleoptera: Tenebrionidae) Using Soil Incorporation of Poultry Manure]]> https://www.researchpad.co/article/N8edcfd4e-eede-42aa-b5cd-b2694a0bd3e8

Abstract

The effectiveness of manure incorporation in reducing the numbers of adult lesser mealworms emerging from caged-layer poultry manure applied to agricultural fields was examined in summer 2002 and 2004. Incorporation treatments included control (no incorporation), disk (7-cm depth), harrow (15-cm depth), chisel plow (30-cm depth), and moldboard plow (33-cm depth) on silt loam soils in New York state. An estimated 55,192 and 183,500 live adult lesser mealworms were applied to the field in 2002 and 2004, respectively. Mortality due to the action of the manure spreader was 32.4% in 2002 and 6.5% in 2004. No significant differences were observed between treatments in 2002. However, moldboard plowing significantly reduced beetle emergence compared with no tillage in 2004. Peak beetle flight was observed 10 and 17 d after manure application in 2002 and 2004, respectively.

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<![CDATA[Attractiveness of an Aggregation Pheromone Lure and Chicken Droppings to Adults and Larvae of Alphitobius diaperinus (Coleoptera: Tenebrionidae)]]> https://www.researchpad.co/article/N48e6a30b-0d5b-4ccd-ac97-1e69d77118bf

Abstract

The chemical cues by which lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) beetles find each other are still unknown. Laboratory two-choice pitfall bioassays were conducted to evaluate the attractiveness of synthetic aggregation pheromone lure to lesser mealworm adults and larvae. All components of this synthetic aggregation pheromone lure, including: (R)-(+)-limonene, (E)-β-ocimene, (S)-(+)-linalool, (R)-(+)-daucene, and 2-nonanone were also tested singly. Chicken dropping volatile compounds and fresh chicken droppings (CD) were evaluated singly or in combination with the pheromone lure. In Arkansas, trapping experiments were conducted in different poultry houses with low, moderate, and high lesser mealworm populations to evaluate the attraction of pheromone lure. Laboratory two-choice pitfall bioassay was found to be a useful and convenient tool for evaluating the attractants before testing them in the poultry house. Greater attraction of adults and larvae to a dose of 20–30 μg pheromone lure was identified in laboratory two-choice pitfall bioassays. Adults and larvae were highly attractive to a combination of fresh CD and pheromone lure, whereas, a combination of chicken dropping volatile and pheromone lure was not significantly attractive. The low attraction of limonene and linalool in the laboratory two-choice pitfall bioassays suggest that either they are nonattractive or attractive only at a narrow range of concentrations. Higher numbers of lesser mealworm adults and larvae were found in traps treated with pheromone lure as compared with untreated controls in field experiments. Results indicate a potential for combining the pheromone lure with the attractive CD compounds to enhance trap efficacy.

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<![CDATA[Unnoticed arrival of two dipteran species in Austria: the synanthropic moth fly Clogmia albipunctata (Williston, 1893) and the parasitic bird louse fly Ornithoica turdi (Olivier in Latreille, 1811)]]> https://www.researchpad.co/article/Ndeb83435-ec9d-4419-aea6-77b4785760e8

In the framework of a mosquito-monitoring program conducted from 2014 to 2018, non-culicid dipteran bycatch was identified to species-level with a focus on Diptera of medical and veterinary importance as part of a biodiversity initiative and barcoding project (“Austrian Barcode of Life”). Two species hitherto not known from Austria, the regularly sampled synanthropic moth fly Clogmia albipunctata (Psychodidae) and a single specimen of the louse fly Ornithoica turdi (Hippoboscidae), were collected in Vienna and Lower Austria. We confirmed identification results using a barcoding approach and provide the first reference sequence for O. turdi.

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<![CDATA[Occurrence, ecological function and medical importance of dermestid beetle hastisetae]]> https://www.researchpad.co/article/Ndddf5a5e-27f2-434a-a9de-df6416b28520

Hastisetae are a specific group of detachable setae characterizing the larvae of Megatominae (Coleoptera: Dermestidae), commonly known as carpet and khapra beetles. These setae are located on both thoracic and abdominal tergites and they are the primary defense of the larva against invertebrate predators. According to previous studies, the main purpose of hastisetae is to work as a mechanical obstacle, but they are also capable to block and kill a predator. Hastisetae, single or aggregate, function as an extremely efficient mechanical trap, based on an entangling mechanism of cuticular structures (spines and hairs) and body appendages (antennae, legs and mouthparts). It is believed that this defensive system evolved primarily to contrast predation by invertebrates, however it has been observed that hastisetae may affect vertebrates as well. Although information on the impacts of vertebrate predators of the beetles is lacking, hastisetae have been shown to be a possible threat for human health as an important contaminant of stored products (food and fabric), work and living environment. Review of past and recent literature on dermestid larvae has revealed that despite these structures indicated as one of the distinctive characters in species identification, very little is known about their ultrastructure, evolution and mechanism of action. In the present work, we will provide the state of knowledge on hastisetae in Dermestidae and we will present and discuss future research perspectives intended to bridge the existing knowledge gaps.

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<![CDATA[Pseudolebinthus lunipterus sp. nov.: a striking deaf and mute new cricket from Malawi (Orthoptera, Gryllidae, Eneopterinae)]]> https://www.researchpad.co/article/N5027f216-1017-4780-90f6-afde366190e5

This article presents an intriguing new cricket species of the tribe Xenogryllini discovered in Northern Malawi. This is the first case of mute and deaf species in the subfamily Eneopterinae; it shows no stridulatory apparatus on short male forewings and no tympana on either side of fore tibiae in both sexes. We introduce the new species and its complete mitogenome and assess phylogenetic relationships based on molecular data obtained from next-generation sequencing genome skimming method. Phylogenetic analyses place the new species within the genus Pseudolebinthus in Xenogryllini, as the sister species of Pseudolebinthus gorochovi Robillard. We describe Pseudolebinthus lunipterus sp. nov., provide illustrations of main morphology, male and female genitalia, photographs of living specimens and information about habitat and update the identification key for species of genus Pseudolebinthus. We discuss the differences between the new species and related taxa and the striking loss of acoustic communication in this cricket.

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<![CDATA[Complete mitogenome of Olidiana ritcheriina (Hemiptera: Cicadellidae) and phylogeny of Cicadellidae]]> https://www.researchpad.co/article/Nf09173c8-9070-4786-8f07-d5a09ed43767

Background

Coelidiinae, a relatively large subfamily within the family Cicadellidae, includes 129 genera and ∼1,300 species distributed worldwide. However, the mitogenomes of only two species (Olidiana sp. and Taharana fasciana) in the subfamily Coelidiinae have been assembled. Here, we report the first complete mitogenome assembly of the genus Olidiana.

Methods

Specimens were collected from Wenxian County (Gansu Province, China) and identified on the basis of their morphology. Mitogenomes were sequenced by next-generation sequencing, following which an NGS template was generated, and this was confirmed using polymerase chain reaction and Sanger sequencing. Phylogenic trees were constructed using maximum likelihood and Bayesian analyses.

Results

The mitogenome of O. ritcheriina was 15,166 bp long, with an A + T content of 78.0%. Compared with the mitogenome of other Cicadellidae sp., the gene order, gene content, gene size, base composition, and codon usage of protein-coding genes (PCGs) in O. ritcheriina were highly conserved. The standard start codon of all PCGs was ATN and stop codon was TAA or TAG; COII, COIII, and ND4L ended with a single T. All tRNA genes showed the typical cloverleaf secondary structure, except for trnSer, which did not have the dihydrouridine arm. Furthermore, the secondary structures of rRNAs (rrnL and rrnS) in O. ritcheriina were predicted. Overall, five domains and 42 helices were predicted for rrnL (domain III is absent in arthropods), and three structural domains and 27 helices were predicted for rrnS. Maximum likelihood and Bayesian analyses indicated that O. ritcheriina and other Coelidiinae members were clustered into a clade, indicating the relationships among their subfamilies; the main topology was as follows: (Deltocephalinae + ((Coelidiinae + Iassinae) + ((Typhlocybinae + Cicadellinae) + (Idiocerinae + (Treehopper + Megophthalminae))))). The phylogenetic relationships indicated that the molecular taxonomy of O. ritcheriina is consistent with the current morphological classification.

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<![CDATA[The microbiota of Drosophila suzukii influences the larval development of Drosophila melanogaster]]> https://www.researchpad.co/article/N116e9746-09f5-423a-88cf-73fa97e9a9b0

Microorganisms play a central role in the biology of vinegar flies such as Drosophila suzukii and Drosophila melanogaster: serving as a food source to both adults and larvae, and influencing a range of traits including nutrition, behavior, and development. The niches utilized by the fly species partially overlap, as do the microbiota that sustain them, and interactions among these players may drive the development of crop diseases. To learn more about how the microbiota of one species may affect the other, we isolated and identified microbes from field-caught D. suzukii, and then characterized their effects on D. melanogaster larval development time in the laboratory. We found that the D. suzukii microbiota consistently included both yeasts and bacteria. It was dominated by yeasts of the genus Hanseniaspora, and bacteria from the families Acetobacteraceae and Enterobacteriaceae. Raising D. melanogaster under gnotobiotic conditions with each microbial isolate individually, we found that some bacteria promoted larval development relative to axenic conditions, but most did not have a significant effect. In contrast, nearly all the yeasts tested significantly accelerated larval development. The one exception was Starmerella bacillaris, which had the opposite effect: significantly slowing larval developmental rate. We investigated the basis for this effect by examining whether S. bacillaris cells could sustain larval growth, and measuring the survival of S. bacillaris and other yeasts in the larval gut. Our results suggest S. bacillaris is not digested by D. melanogaster and therefore cannot serve as a source of nutrition. These findings have interesting implications for possible interactions between the two Drosophilia species and their microbiota in nature. Overall, we found that microbes isolated from D. suzukii promote D. melanogaster larval development, which is consistent with the model that infestation of fruit by D. suzukii can open up habitat for D. melanogaster. We propose that the microbiome is an important dimension of the ecological interactions between Drosophila species.

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<![CDATA[Host dietary specialization and neutral assembly shape gut bacterial communities of wild dragonflies]]> https://www.researchpad.co/article/Nf8861876-1ea4-461a-b805-36570bca6ddd

Host-associated gut microbiota can have significant impacts on host ecology and evolution and are often host-specific. Multiple factors can contribute to such host-specificity: (1) host dietary specialization passively determining microbial colonization, (2) hosts selecting for specific diet-acquired microbiota, or (3) a combination of both. The latter possibilities indicate a functional association and should produce stable microbiota. We tested these alternatives by analyzing the gut bacterial communities of six species of wild adult dragonfly populations collected across several geographic locations. The bacterial community composition was predominantly explained by sampling location, and only secondarily by host identity. To distinguish the role of host dietary specialization and host-imposed selection, we identified prey in the guts of three dragonfly species. Surprisingly, the dragonflies–considered to be generalist predators–consumed distinct prey; and the prey diversity was strongly correlated with the gut bacterial profile. Such host dietary specialization and spatial variation in bacterial communities suggested passive rather than selective underlying processes. Indeed, the abundance and distribution of 72% of bacterial taxa were consistent with neutral community assembly; and fluorescent in situ hybridization revealed that bacteria only rarely colonized the gut lining. Our results contradict the expectation that host-imposed selection shapes the gut microbiota of most insects, and highlight the importance of joint analyses of diet and gut microbiota of natural host populations.

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