Insects, Volume 12, Issue 9 (September 2021) – 86 articles

Field-based residual bioassays and residue analysis were conducted to assess the field performance and toxicity longevity of different insecticides that had previously been associated with resistance of Choristoneura rosaceana populations collected from apple and cherry orchards. In this study, 12–24 h-old larvae of apple and cherry populations were exposed to apple and cherry leaf samples, respectively, at post-application intervals and a susceptible population served as a reference of each. In the apple and cherry trials, the order of residual longevity of insecticides that effectively controlled the tested populations was as follows: bifenthrin and spinetoram (apple: 14, cherry 21-day post-application), phosmet (apple: 7, cherry 14-day post-application), chlorantraniliprole (apple: 7-day post-application), and indoxacarb and emamectin benzoate (apple: 1, cherry 7-day post-application). Compared to the susceptible population, the resistant populations resulted in a measurable loss of field performance, or “practical resistance”, for the insecticides emamectin benzoate (at 7-day post-application), chlorantraniliprole (at 21-day post-application), and indoxacarb (at all post-application intervals) in the apple trials, while in cherry trial just indoxacarb at 7-day post-application showed a reduced efficacy. In terms of long-lasting residues, only chlorantraniliprole and indoxacarb maintained measurable leaf residues over all post-application intervals while the leaf residues of the other compounds had largely degraded within the first 7 days. These findings can help fruit growers make adjustments to their spray/re-application intervals and optimally utilize important chemical tools in their integrated pest management programs. Full article

Lipoptena fortisetosa, a deer ked native to Japan, has established itself in several European countries and was recently recorded in Italy. This hippoboscid ectoparasite can develop high density populations, causing annoyance to animals and concern regarding the potential risk of transmitting pathogens to humans. No monitoring or control methods for L. fortisetosa have been applied or tested up to now. This research evaluated the possible response of L. fortisetosa winged adults to different colours as the basis for a monitoring and control strategy. In the summer of 2020, a series of six differently coloured sticky panels were randomly set as traps in a wooded area used by deer for resting. The results indicated a clear preference of the deer ked for the blue panels that caught the highest number of flies during the experimental period. Lower numbers of flies were trapped on the red, green, black, and white panels, with the yellow panels recording the fewest captures. The response clearly demonstrates that this species displays a colour preference, and that coloured traps might be useful for monitoring and limiting this biting ectoparasite in natural areas harbouring wildlife and visited by people. Full article

The short neuropeptide F (sNPF) is an essential signaling molecule that is evolutionarily conserved and involved in a broad range of physiological functions in the invertebrates, by interacting with sNPF receptors, which belong to G protein-coupled receptors (GPCR). However, the function of sNPF in regulating the food intake of Dendroctonus armandi has been unclear. In this study, we cloned and characterized cDNAs encoding sNPF and sNPF receptor in the D. armandi and made bioinformatics predictions on the deduced amino acid sequences. They had a high degree of similarity to that of Dendroctonus ponderosa. Quantitative real-time reverse transcription PCR (qRT-PCR) revealed that the transcript levels of both sNPF and sNPFR varied across developmental stages and body parts. In addition, the sNPF and sNPFR expression levels were upregulated in starved beetles, and the expression levels recovered after re-feeding. Furthermore, RNAi knockdown by the injection of sNPF and sNPFR dsRNA into beetles significantly increased mortality and reduced their food intake and body weight, and also caused decrease of glycogen and free fatty acid and increase of trehalose. These results indicate that sNPF signaling pathway plays an important role in the regulation of food intake and provides a potential molecular target for the eco-friendly control strategies of this pest. Full article

The ability to recognize the own nest is a basic skill in nest constructing solitary bees. Osmia cornuta females use a dual mechanism of visual orientation to approach a nest and olfactory verification of the tube when entering it. Occupied tubular cavities were steadily marked by the resident female. Nest marking substances originate from Dufour’s gland and cuticle, enriched by external volatiles. Scent tags were dominated by alkanes and alkenes in a species-specific mixture enriched by small amounts of fatty acid esters, alcohols, and aldehydes. The individual nest tags are sufficiently variable but do not match perfectly with the nesting female. Furthermore, tags are not consistent over time, although females continue in marking. Besides the correct position of the entrance in space, bees have to learn also the bouquet of the used cavity and update their internal template at each visit to recognize their own nest by its actual smell. Due to the dominance of the species-specific hydrocarbon pattern, nest marks may function not only as an occupied sign but may also provide information on the species affiliation and constitution of the nest owner. Full article

Apis mellifera (honeybees) are a well-established model for the study of learning and cognition. A robust conditioning protocol, the olfactory conditioning of the proboscis extension response (PER), provides a powerful but straightforward method to examine the impact of varying stimuli on learning performance. Herein, we provide a protocol that leverages PER for classroom-based community or student engagement. Specifically, we detail how a class of high school students, as part of the Ryukyu Girls Outreach Program, examined the effects of caffeine and dopamine on learning performance in honeybees. Using a modified version of the PER conditioning protocol, they demonstrated that caffeine, but not dopamine, significantly reduced the number of trials required for a successful conditioning response. In addition to providing an engaging and educational scientific activity, it could be employed, with careful oversight, to garner considerable reliable data examining the effects of varying stimuli on honeybee learning. Full article

Bees play a key role in natural and agro-ecosystems and their diversity is worldwide threatened by anthropogenic causes. Despite this, there is little awareness of the existence of the numerous species of wild bees, and the common name “bee” is very often exclusively associated with Apis mellifera. Our aim was to create a citizen science project in Italy with the following objectives: (a) raising awareness of the importance and diversity of bees, (b) obtaining data on the biology, ecology and distribution of Italian species, and (c) launching the monitoring of alien bees. The first step of the project was to create a website platform with a section containing informative datasheets of the wild bee families and of the most common bee genera present in Italy, a form to send reports of observed bees and an interactive map with all citizen’s reports. During the 2 years of the project 1086 reports were sent by 269 users, with 38 Apoidea genera reported on 190 plant genera; furthermore, 22 reports regarding the alien species Megachile sculpturalis arrived. The majority of bees (34 genera) were observed on spontaneous plants, including 115 genera native to Italy. Considering the increasing number of reports and data obtained in these first two years of the project, our objectives seem to be achieved. Future steps will be to outline the profile of beewatchers, to plan activities in a more targeted way, and also to start some sub-projects for conservation purposes. Full article

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), a pest of Asian origin, has been causing severe damage to Italian agriculture. The application of classical biological control by the release of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), an exotic egg parasitoid, appears to be one promising solution. In Italy, releases of T. japonicus in the field were authorized in 2020. In this study, some parameters that could influence the rearing of T. japonicus in insectaries were investigated. A significantly higher production of progeny was observed on host eggs stored at 6 °C (86.5%) compared to −24 °C (48.8%) for up to two months prior to exposure to parasitism. There were no significant differences in progeny production from single females in a vial provided with only one egg mass (83.2%) or 10 females inside a cage with 6 egg masses (83.9%). The exposure of parasitoids to refrigerated (6 °C) egg masses of H. halys for 72 h led to a significantly higher production of progeny (62.1%) compared to shorter exposures for 48 (44.0%) or 24 h (37.1%). A decline in production of progeny by the same female was detected between the first (62.1%) and the second parasitization (41.3%). Adult parasitoids stored at 16 °C for up to 90 days had an 87.1% survival rate, but a significant decrease in progeny production was detected. These parameters could be adjusted when rearing T. japonicus for specific aims such as the production of individuals for field release or colony maintenance. Full article

Historical pharmacies are valuable artistic, cultural, and scientific assets. In Italy, 482 historical pharmacies have been catalogued thus far, among which is the Navarra-Bragliani Pharmacy in Ferrara, whose wood furniture dates back to the 18th century. A study on insects causing biodeterioration was carried out for the first time on this valuable asset in order to monitor and preserve it. Insect samples were collected during surveys and examined by stereomicroscopy and scanning electron microscopy, using taxonomical keys for identification. The results revealed the presence of three species of Coleoptera—the first one specialised to attack wood materials, the second one polyphagous, and the third one feeding on materials of animal origin. The data obtained in this investigation may be useful for the preservation of the precious furnishing of the historical Navarra-Bragliani Pharmacy for performing similar studies on other ancient pharmacies aimed to protect these valuable cultural and scientific assets. Full article

Exogenous calcium (Ca) has been used to induce host plant resistance in response to abiotic and biotic stresses, including from thrips attack. The aim of this study was to determine whether exogenously applied Ca affects the performance of Frankliniella occidentalis. We assessed the development time, total longevity, reproduction, and population parameters of F. occidentalis, and its preference choice on Ca-treated or untreated control kidney bean plants under laboratory conditions. The results showed that F. occidentalis fed on Ca-treated leaves had a longer developmental time but lower longevity (female and male) and fecundity than F. occidentalis fed on control leaves. Population parameters, including the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R₀), were all found higher in control leaves than in Ca-treated leaves, and the mean generation time (T) was shorter. In preference choices, the number of thrips on control plants was higher than the number of thrips on Ca-treated kidney bean plants. Overall, our results indicated that exogenous Ca pretreatment on kidney bean plants affected the life history and preference choice of F. occidentalis, suggesting Ca might be used as a promising elicitor of inducible plant defense against thrips. Full article

Transposable elements (TEs) play a significant role in both eukaryotes and prokaryotes genome size evolution, structural changes, duplication, and functional variabilities. However, the large number of different repetitive DNA has hindered the process of assembling reference genomes, and the genus level TEs diversification of the grasshopper massive genomes is still under investigation. The genus Calliptamus diverged from Peripolus around 17 mya and its species divergence dated back about 8.5 mya, but their genome size shows rather large differences. Here, we used low-coverage Illumina unassembled short reads to investigate the effects of evolutionary dynamics of satDNAs and TEs on genome size variations. The Repeatexplorer2 analysis with 0.5X data resulted in 52%, 56%, and 55% as repetitive elements in the genomes of Calliptamus barbarus, Calliptamus italicus, and Calliptamus abbreviatus, respectively. The LINE and Ty3-gypsy LTR retrotransposons and TcMar-Tc1 dominated the repeatomes of all genomes, accounting for 16–35% of the total genomes of these species. Comparative analysis unveiled that most of the transposable elements (TEs) except satDNAs were highly conserved across three genomes in the genus Calliptamus grasshoppers. Out of a total of 20 satDNA families, 17 satDNA families were commonly shared with minor variations in abundance and divergence between three genomes, and 3 were Calliptamus barbarus specific. Our findings suggest that there is a significant amplification or contraction of satDNAs at genus phylogeny which is the main cause that made genome size different. Full article

The brown planthopper (BPH) is one of the main pests endangering rice yields. The development of rice varieties harboring resistance genes is the most economical and effective method of managing BPH. To identify new BPH resistance-related genes, a total of 123 rice varieties were assessed for resistance and durable resistance. Three varieties were immune, and nine were highly resistant to BPH. After whole-genome resequencing of all 123 varieties, 1,897,845 single nucleotide polymorphisms (SNPs) were identified. Linkage disequilibrium (LD) decay analysis showed that the average LD of the SNPs at 20 kb was 0.30 (r²) and attenuated to half value (~0.30) at a distance of about 233 kb. A genome-wide association study (GWAS) of durable resistance to BPH was conducted using the Fast-MLM model. One quantitative trait locus, identified on chromosome 2, included 13 candidate genes. Two candidate genes contained a leucine-rich repeat and CC-NBS-LRR or NB-ARC domains, which might confer resistance to pests or diseases. Interestingly, LOC_Os02g27540 was highly expressed and was induced by BPH; GWAS identified potential rice genes coding for durable resistance to BPH. This study helps to elucidate the mechanism of durable resistance to BPH in rice and provides essential genetic information for breeding and functional verification of resistant varieties. Full article

The Eurasian malaria vector Anopheles messeae is a widely spread and genetically diverse species. Five widespread polymorphic chromosomal inversions were found in natural populations of this mosquito. A cryptic species, Anopheles daciae, was differentiated from An. messeae by the presence of several nucleotide substitutions in the Internal Transcribed Spacer 2 (ITS2) region of ribosomal DNA. However, because of the absence of a high-quality reference cytogenetic map, the inversion polymorphisms in An. daciae and An. messeae remain poorly understood. Moreover, a recently determined heterogeneity in ITS2 in An. daciae questioned the accuracy of the previously used Restriction Fragment Length Polymorphism (RFLP) assay for species diagnostics. In this study, a standard-universal cytogenetic map was constructed based on orcein stained images of chromosomes from salivary glands for population studies of the chromosomal inversions that can be used for both An. messeae and An. daciae. In addition, a new ITS2-RFLP approach for species diagnostics was developed. Both methods were applied to characterize inversion polymorphism in populations of An. messeae and An. daciae from a single location in Western Siberia in Russia. The analysis demonstrates that cryptic species are remarkably different in their frequencies of chromosomal inversion variants. Our study supports previous observations that An. messeae has higher inversion polymorphism in all autosomes than the cryptic species An. daciae. Full article

Classical biological control is an important method for controlling invasive alien weeds. Univoltine insects can be highly effective biological control agents of annual weeds because they are well synchronized with their host plant. However, having only one generation per year makes it difficult and slow to multiply them in the laboratory for initial field releases. If it were possible to terminate reproductive diapause early, then we could rear multiple generations per year, which would greatly increase annual production. We used a recently approved biocontrol agent, Ceratapion basicorne (a univoltine weevil), for yellow starthistle (Centaurea solstitialis) as a model system to study the use of two insect hormones, 20-hydroxyecdysone (20E) and methoprene, to terminate reproductive diapause. Methoprene (1 μg applied topically) terminated reproductive diapause of female weevils, whereas doses of 0.0, 0.01 and 0.1 μg did not. The combination of methoprene and 20E had a stronger effect and induced an increase in eggs (1.51 ± 0.16 eggs/day, mean ± SE) compared with a methoprene only group (1.00 ± 0.13 eggs/day), and a control group (0.21 ± 0.04 eggs/day). Thus, topical application of these hormones should enable us to rear the weevil out of its normal season and produce more than one generation per year, which will increase productivity of mass-rearing it for field release. Once released in the field, the insect would continue as a univoltine agent that is well-synchronized with its host plant. Full article

The effects of high temperature on the developmental, morphological, and fecundity characteristics of insects, including biological invaders and their accompanying natural enemies, are clear. Phenacoccus solenopsis (Homoptera: Pseudococcidae) is an aggressive invasive insect pest worldwide. Aenasius bambawalei (=Aenasius arizonensis Girault) (Hymenoptera: Encyrtidae) is a predominant accompanying parasitoid of this mealybug. Our previous studies showed that temperature change induced an increase in the female offspring ratio of A. bambawalei. However, whether this increase is the result of a shortened or enhanced development period of the reproductive systems of A. bambawalei remains unknown. Here, we compared the pupal development, hind tibia of female adults, and fecundity of A. bambawalei under different temperatures to clarify the development and morphological changes induced by high temperature and to better understand its potential as an accompanying natural enemy. Our results showed that, at a high temperature (36 °C), the pupal developmental duration of A. bambawalei was only 0.80 times that of the control, and the length of the hind tibia was 1.16 times that of the control. Moreover, high temperature accelerated the developmental rate of gonads and increased the numbers of eggs and sperm. These results indicated that experimental warming shortened the pupal developmental duration, altered the hind tibia length of female adults, and facilitated the fecundity of A. bambawalei. These findings will help to understand the adaptation mechanisms of accompanying natural enemies. Furthermore, these findings will help to make use of this behavior to effectively control invasive pests. Full article

To study the evolution of gene function and a species, it is essential to characterize the tandem repetitive sequences distributed across the genome. Cas9-based enrichment combined with nanopore sequencing is an important technique for targeting repetitive sequences. Cpf1 has low molecular weight, low off-target efficiency, and the same editing efficiency as Cas9. There are numerous studies on enrichment sequencing using Cas9 combined with nanopore, while there are only a few studies on the enrichment sequencing of long and highly repetitive genes using Cpf1. We developed Cpf1-based enrichment combined with ONT sequencing (CEO) to characterize the B. mori FibH gene, which is composed of many repeat units with a long and GC-rich sequence up to 17 kb and is not easily amplified by means of a polymerase chain reaction (PCR). CEO has four steps: the dephosphorylation of genomic DNA, the Cpf1 targeted cleavage of FibH, adapter ligation, and ONT sequencing. Using CEO, we determined the fine structure of B. moriFibH, which is 16,845 bp long and includes 12 repetitive domains separated by amorphous regions. Except for the difference of three bases in the intron from the reference gene, the other sequences are identical. Surprisingly, many methylated CG sites were found and distributed unevenly on the FibH repeat unit. The CEO we established is an available means to depict highly repetitive genes, but also a supplement to the enrichment method based on Cas9. Full article

Lycoriella species (Sciaridae) are responsible for significant economic losses in greenhouse production (e.g., mushrooms, strawberries, and nurseries). The current distributions of species in the genus are restricted to cold-climate countries. Three species of Lycoriella are of particular economic concern in view of their ability to invade areas in countries across the Northern Hemisphere. We used ecological niche models to determine the potential for range expansion under future climate change scenarios (RCP 4.5 and RCP 8.5) in the distribution of these three species of Lycoriella. Stable environmental suitability under climate change was a dominant theme in these species; however, potential range increases were noted in key countries (e.g., USA, Brazil, and China). Our results illustrate the potential for range expansion in these species in the Southern Hemisphere, including some of the highest greenhouse production areas in the world. Full article

Olive lace bugs (Hemiptera: Tingidae) are small sap-sucking insects that feed on wild and cultivated Olea europaea. The diversity of olive lace bug species in South Africa, the most important olive producer on the continent, has been incompletely surveyed. Adult specimens were collected in the Western Cape province for morphological and DNA-based species identification, and sequencing of complete mitogenomes. Cysteochila lineata, Plerochila australis, Neoplerochila paliatseasi and Neoplerochila sp. were found at 12 sites. Intra- and interspecific genetic divergences and phylogenetic clustering in 30 species in 18 genera of Tingidae using new and publicly available DNA barcodes showed high levels of congruity between taxonomic and genetic data. The phylogenetic position of the four species found in South Africa was inferred using new and available mitogenomes of Tingidae. Notably, olive lace bugs formed a cluster of closely related species. However, Cysteochila was non-monophyletic as C. lineata was recovered as a sister species to P. australis whereas Cysteochila chiniana, the other representative of the genus, was grouped with Trachypeplus jacobsoni and Tingis cardui in a different cluster. This result suggests that feeding on O. europaea may have a common origin in Tingidae and warrants future research on potential evolutionary adaptations of olive lace bugs to this plant host. Full article

Flytraps can be used on farms to monitor the populations of primary strike flies (Lucilia cuprina and Lucilia sericata) and, hence, offer a view regarding the incidence of flystrike on sheep. This study aimed to contrast the specificity and effectiveness of the LuciTrap with its combination of three chemical lures (Lucilures) and the Western Australian Trap with three bait types (LuciLure, Sheep liver with 30% sodium sulphide and squid). A mean model and rate model were fitted to the data. The mean model showed no difference (p > 0.05) in the mean weekly catch for L. cuprina between the Western Australian Trap with LuciLures and the Western Australian Trap baited with sheep liver with 30% sodium sulphide (p < 0.05). Whereas, for L. sericata, no difference (p > 0.05) was found between the Western Australian Trap with LuciLures, the Western Australian Trap baited with sheep liver with 30% sodium sulphide and the LuciTrap. The rate model illustrated that the Western Australian Trap with sheep liver with 30% sodium sulphide and LuciTrap did not differ (p > 0.05) for L. cuprina and L. sericata. Combined, these results indicate that New Zealand farmers can use either the LuciTrap or the Western Australian Trap with sheep liver with 30% sodium sulphide to monitor these target species. Full article

Coupling several natural and synthetic lures with aggregation pheromones from the palm weevils Rhynchophorus palmarum and R. ferrugineus reveals a synergy that results in an increase in pest captures. The combined attraction of pure pheromones, ethyl acetate, and decaying sweet and starchy plant tissue increases the net total of mass-trapped weevils. The 2018 entrance of the red palm weevil (RPW) into South America has threatened palm-product income in Brazil and other neighboring countries. The presence of the new A1 quarantine pest necessitates the review of all available options for a sustainable mass-trapping, monitoring, and control strategy to ultimately target both weevils with the same device. The effective lure-blend set for the mass-trapping system will attract weevils in baiting and contaminating stations for entomopathogenic fungi that the same weevils will spread. Full article

The gypsy moth, Lymantria dispar, is a polyphagous forest pest worldwide. The baculovirus, Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) is a natural pathogen of L. dispar. The Toll-like receptors (TLR) pathway plays a crucial role in both innate and adaptive immunity in animals. However, The TLR pathway and its underlying immune mechanism against baculovirus in L. dispar have not been explored. In this study, eleven TLRs and five downstream TLR pathway components were identified and characterized from L. dispar. Structural analysis indicated that intracellular Toll/interleukin-1 receptor (TIR) domains of LdTLRs and LdMyD88 contained three conserved motifs, and the 3D structures of TIR domains of LdTLRs possessed similar patterns in components arrangement and spatial conformation. The TLR proteins of L. dispar were placed into five monophyletic groups based on the phylogenetic analysis. LdTLR1, 2, 5, 6, 7, 8 and all identified downstream TLR pathway factors were highly induced upon LdMNPV infection, indicating that the TLR pathway of L. dispar was activated and might play a role in the immune response to LdMNPV infection. Collectively, these results help elucidate the crucial role of the TLR pathway in the immune response of L. dispar against LdMNPV, and offer a foundation for further understanding of innate immunity of the pest. Full article

Pyrethroid resistance is widespread in malaria vectors. However, differential mortality in discriminating dose assays to different pyrethroids is often observed in wild populations. When this occurs, it is unclear if this differential mortality should be interpreted as an indication of differential levels of susceptibility within the pyrethroid class, and if so, if countries should consider selecting one specific pyrethroid for programmatic use over another. A review of evidence from molecular studies, resistance testing with laboratory colonies and wild populations, and mosquito behavioural assays were conducted to answer these questions. Evidence suggested that in areas where pyrethroid resistance exists, different results in insecticide susceptibility assays with specific pyrethroids currently in common use (deltamethrin, permethrin, α-cypermethrin, and λ-cyhalothrin) are not necessarily indicative of an operationally relevant difference in potential performance. Consequently, it is not advisable to use rotation between these pyrethroids as an insecticide-resistance management strategy. Less commonly used pyrethroids (bifenthrin and etofenprox) may have sufficiently different modes of action, though further work is needed to examine how this may apply to insecticide resistance management. Full article

Female choice may be linked to population density if the expected encounter rates with potential mates affects choosiness (the energy and risk engaged to express mate preferences). Choosiness should covary with male availability, which could be assessed using the social cues available during development. We tested whether the exposure of juvenile females to cues of male density affected the mechanisms of choosiness of adult Latrodectus hasselti spiders in two experiments simulating natural contexts. The juvenile females were exposed to (1) volatile chemicals from two densities of adult males (airborne cues), and (2) tactile, vibrational and chemical cues from adult males or other females (cohabitation cues). As adults, the females mated readily, regardless of the treatment, but there was strong evidence for post-copulatory mechanisms of choosiness in females exposed to cues of high male availability. These included abbreviated matings (in both experiments), cannibalism of the males before the mating was complete (cohabitation), and, remarkably, a reduction in the successful placement of internal sperm plugs (cohabitation). These shifts decrease the likelihood that the first mate would monopolize paternity if the female chose to mate again. We conclude that female choosiness may impose a strong selection on males despite the high mating rates, and these effects can hinge on the cues of male availability detected by juveniles. Full article

Citrus greening disease is devastating the citrus industry in Florida, and the conventional synthetic pesticide applications used to control the vector, the Asian citrus psyllid (AsCP), Diaphorina citri, are rapidly becoming unsustainable. Various laboratory experiments indicate that the entomopathogenic fungus Cordyceps javanica, alone and in combination with horticultural oils, may offer a more sustainable strategy for the management of AsCP. Field studies conducted in 2018 and 2019 in mature citrus indicated that C. javanica alone, C. javanica mixed with white oil, and the chemical standard spinetoram mixed with white oil significantly suppressed AsCP adult populations by 61–83% up to 14 days after treatment in 2018, although colony-forming units of C. javanica were still present on the leaves 21 days after treatment (DAT). Only spinetoram + oil significantly suppressed AsCP, by 100%, up to 7 DAT in 2019. Natural enemies of AsCP, including lady beetles, lacewing larvae and the parasitoid Tamarixia radiata, were observed in the fungal treatments and the untreated control. The AsCP suppression by C. javanica and its compatibility with beneficial organisms suggest the potential use of this entomopathogenic fungus in citrus-integrated pest management. Full article

The Aphelinus asychis female adult is an important arrhenotocous parthenogenesis parasitoid of Myzus persicae, and its reproductive mode is beneficial for the population continuation of A. asychis by way of multiple mating and backcross. To explore the effect of mating on the population fitness and control efficiency of A. asychis, its mating frequency and backcross were observed under laboratory conditions. The results showed that most matings in A. asychis involved four distinct stages: courtship, pre-copulatory, copulation, and post-copulatory behaviours. Only the duration of courtship increased significantly with an increase in copulation frequency for females, and the courtship duration of A. asychis females mated with different males were significantly shorter than those mated with the same male at the same mating times, which suggested that A. asychis females might prefer to mate with different males to enrich the genotype of their offspring. The total number of mummified aphids and the female and male longevity decreased significantly with an increase in mating frequency. On the contrary, female progenies increased significantly with an increase of mating frequency, suggesting that sperm limitation might occur in females when they only mated once. These results imply that females might prefer to receive more sperm by mating multiple times in their life span. In addition, we found that the intrinsic rate of increase (r) of A. asychis of the control group (0.2858 d⁻¹) was significantly greater than that in the backcross treatment (0.2687 d⁻¹). The finite killing rate (θ) of A. asychis of the control group was similar to that in the backcross treatment, which showed that this treatment had a negligible negative effect on the control efficiency of A. asychis. In conclusion, the results showed that multiple mating increased the number and proportion of A. asychis female progenies but shortened the longevity of female and male adults, while the negative effect of backcross on the control efficiency of A. asychis was negligible. Full article

Antennal sensilla play an essential role in insect life because they receive environmental cues. Dioryctria rubella is an important pine pest in China, but information on the morphology and distribution of its sensilla is limited. To elucidate the mechanism of insect-plant chemical communication, we examined the insect antennae and sensilla by scanning electron microscopy. The results showed that the antennae of D. rubella were filiform and consisted of a basal scape, a pedicel, and a flagellum with tapered flagellomeres. We identified seven types of sensilla, including trichodea, coeloconica, auricillica, basiconica, styloconica (two subtypes), Böhm’s bristles, and squamiformia, all of which were distributed on the antennae of both sexes. Nevertheless, some sensilla exhibited various degrees of sexual dimorphism; for instance, sensilla trichodea, squamiformia, and basiconica were more abundant in males than in females. Many pores were observed on the surface of the cuticular wall in sensilla trichodea and auricillica, and their biological function may be related to olfaction. This study presented a thorough inventory of sensilla on the antennae of D. rubella and laid a solid foundation for future functional studies. Full article

Aedes albopictus is an invasive mosquito species responsible for local transmission of chikungunya and dengue viruses in Europe. In the absence of available treatments, insecticides-based control remains one of the most important viable strategies to prevent emerging problems. Diflubenzuron (DFB) and Bacillus thuringiensis var. israelensis (Bti) are among the most commonly used larvicides for Ae. albopictus control with consequent concerns for the potential development of resistance. Studies on the resistance emergence in Ae. albopictus and its persistence in the wild to both DFB and Bti are essential for the efficient and sustainable planning of the control programmes. In this context, larvae from a recently laboratory established population were subjected to increasing selective pressure for nine successive generations using both DFB and Bti. The resistance levels and the overwintering success of the selected populations relative to control (colonies that received no selection) were determined. Results revealed an 8.5- and 1.6-fold increase on the resistance levels following selection with DFB and Bti, respectively. The selection process to both larvicides had no apparent impacts on the overwintering capability relative to control, suggesting the successful persistence of the selected individuals in the wild on an annual base. Full article

The subfamily Lamiinae is the most taxonomically diverse subfamily of Cerambycidae, but relationships between tribes of Lamiinae are still unresolved. In order to study the characteristics of the mitogenomes of Lamiinae and the tribal-level phylogenetic relationships, we sequenced the mitogenomes of two species representing two tribes, Agapanthia amurensis (Agapanthiini) and Moechotypa diphysis (Ceroplesini), with a total length of 15,512 bp and 15,493 bp, respectively. The gene arrangements of these two new mitogenomes were consistent with the inferred ancestral insect mitogenomes. Each species contained 37 typical mitochondrial genes and a control region (A + T-rich region), including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs). All PCGs initiated with the standard start codon ATN, and terminated with the complete stop codons of TAA and TAG, or incomplete stop codon T. All tRNAs could be folded into a clover-leaf secondary structure except for trnS1, in which the dihydrouridine (DHU) arm was reduced. Moreover, we studied the phylogenetic relationships between some tribes of Lamiinae based in mitochondrial PCGs in nucleotides; our results show that the relationships were as follows: (Onciderini + ((Apomecynini + Acanthocinini) + ((Ceroplesini + Agapanthiini) + ((Mesosini + Pteropliini) + ((Dorcaschematini + (Saperdini 1 + (Phytoeciini + Saperdini 2))) + (Batocerini + Lamiini)))))). Full article

Introduction: The surveillance of mosquito vectors is important for the control of arboviruses diseases worldwide. Detailed information on the bionomics and distribution of their main vectors, Aedes aegypti and Aedes albopictus, is essential for assessing disease transmission risk and for better planning of control interventions. Methods: Entomological surveys were carried out from November 2019 to November 2020 in six localities of Yaoundé city following a transect from urban to rural settings: two urban (Obili, Mvan), two peri-urban (Simbock, Ahala) and two rural areas (Lendom, Elig-essomballa)—during rainy and dry seasons. All water containers were inspected. Aedes mosquito abundance, species distribution and seasonal distribution patterns were compared using generalized linear models. Stegomyia indexes were estimated to determine the risk of arbovirus transmission. Results: A total of 6332 mosquitoes larvae were collected (2342 in urban areas, 1694 in peri-urban areas and 2296 in rural sites). Aedes species recorded included Ae. albopictus, Ae. aegytpi, Ae. simpsoni and Aedes spp. High mosquito abundance was registered in the rainy season (4706) compared to the dry season (1626) (p < 0.0001). Ae. albopictus was the most abundant Aedes species in urban (96.89%) and peri-urban (95.09%) sites whereas Ae. aegypti was more prevalent in rural sites (68.56%) (p < 0.0001). Both species were found together in 71 larval habitats. Ae. albopictus was mostly found in discarded tires (42.51%), whereas Ae. aegypti was more prevalent in plastic containers used for storing water (65.87%). The majority of Aedes mosquitoes’ breeding places were situated close to human dwellings (0–10 m). Conclusion: Uncontrolled urbanization seems to greatly favour the presence of Aedes mosquito species around human dwellings in Yaoundé. Controlling Aedes mosquito distribution is becoming urgent to reduce the risk of arbovirus outbreaks in the city of Yaoundé. Full article

The potential use of invertebrates as bioreactors to treat environmental pollutants is promising and of great interest. Three types of the persistent organic pollutants (POPs), namely pentachlorophenol (PCP), PAHs (naphthalene and phenanthrene) and dieldrin (DLN), were spiked in soil and treated by using Oryctes rhinoceros larvae, a known pest of coconut trees in southeast Asia, and also the indicators of POP toxicity and the fate and degradability of the ingested POPs were assessed. The larvae were tested at various levels of the POPs and went through an acclimation process. Without acclimation, the tolerance limits of the larvae toward PCP, PAHs and DLN were 200, 100 and 0.1 mg/kg-soil, respectively, yet with acclimation, the tolerance levels increased to 800, 400 and 0.5 mg/kg-soil, respectively. Biodegradation rates of all the tested POPs were >90% by week 2, with <5% and nearly 0% remaining in the feces and body of the larvae, respectively. The results suggest that the use of the beetle larvae in soil POP decontamination is doable. Full article

By any measure, such as abundance, species diversity or geographic range, the Simulium ornatum species group is one of the most successful Palearctic taxa of black flies. To explore potential diversity in this group in the Tian Shan range of Central Asia, we focused on Kyrgyzstan, in which three nominal morphospecies have been recorded. Among our samples, we morphologically identified S. mesasiaticum Rubtsov and a second possible species tentatively identified as S. ferganicum Rubtsov. By analyzing banding patterns of the larval polytene chromosomes, we discovered two fixed inversions, two sex-linked rearrangements, and 19 autosomal rearrangements, including supernumerary B chromosomes. The chromosomal data indicate minimal diversity of only one or two species across the surveyed area of nearly 50,000 km². Mitochondrial DNA (CO1) sequences fell into three distinct clusters, possibly representing separate species. The chromosomal, molecular, and morphological data indicate that Kyrgyz populations are unique within the S. ornatum group, but the data sets are not entirely congruent. Thus, reconciling data sets and assigning existing names is tentative. Simulium mesasiaticum is linked with undifferentiated sex chromosomes, one of the three CO1 clades, and higher elevations, whereas S. ferganicum is tenuously associated with differentiated sex chromosomes, a separate CO1 clade, and lower elevations. These associations leave one Kyrgyz larva, which is in a third CO1 clade, unlinked to a formal species name. Our analyses also indicate that S. ornatum Meigen sensu stricto, contrary to previous reports, does not occur in Kyrgyzstan and should be deleted from the country’s faunal list. Full article