Instar Nymphs Research Articles

Reevaluation of taxonomic identity of the recently introduced invasive planthopper, Pochazia shantungensis (Chou & Lu, 1977) (Hemiptera: Fulgoroidea: Ricaniidae) in Japan

The taxonomic identity of the invasive Asian Ricaniid planthopper, Pochazia shantungensis (Chou & Lu, 1977) in Japan is reevaluated. This originally Chinese planthopper is highly polyphagous and has recently become an important pest in Korea. In 2015, this species was first documented from Sakai, Osaka Prefecture and has been widespread since then. The genital structures, wings and fifth instar nymph are described and illustrated. The host plants in Japan are also documented with photographs. The male genitalia of a similar species, P. sublimata (Jacobi, 1916), are illustrated as well. As a recently introduced pest in Japan, P. shantungensis needs to be monitored for its potential spread and for the damage it may cause to agriculture.

Types and Fecundity of Neotenic Reproductives Produced in 5-Year-Old Orphaned Colonies of the Drywood Termite, Cryptotermes domesticus (Blattodea: Kalotermitidae)

Orphaned colonies of Cryptotermes domesticus readily produce replacement reproductives and continue propagation. In this study, we aimed to investigate the production and fecundity of neotenic reproductives in 5-year-old colonies of C. domesticus after orphaning. All 15 experimental colonies were successfully re-established by the neotenic reproductive pair. Three types of neotenic reproductives with various wing-bud lengths were observed: type I with micro wing buds, type II with short wing buds, and type III with long wing buds. Four patterns of pairs made up of these neotenics, namely, type I + type II, type I + type III, type II + type II, and type II + type III, exhibited reproductive capacities similar to those of the primary reproductive pair. We speculated that these neotenic reproductives were derived from various nymphal instars. The 5-year-old colonies had three instars of nymphs, with the majority being in the second instar, followed by the first. Thus, the combination of neotenic reproductives with short wing buds and micro wing buds was the dominant differentiation pathway of the orphaned colonies. After the removal of the original primary reproductive pair, the nymphs matured into neotenic reproductives and took over reproduction in the colony in 107.40 ± 15.18 days. This study highlights the importance of quarantine and routine inspection of wood, as well as the significance of early prevention and control of C. domesticus infestation in wood. Moreover, this study confirms the high differentiation and reproductive capacities of C. domesticus.

Morphometric study of the legs of the main Chagas vector, Triatoma infestans (Hemiptera: Reduviidae)

In triatomines, vectors of Chagas disease, active dispersal takes place by walking and flying. Flight has received more attention than walking although the last is the dispersal modality used by nymphs due to their lack of wings and also used by adults, which would facilitate the colonization and reinfestation of houses after vector control actions. The present work studied the morphometrical variation of Triatoma infestans legs, the main vector of Chagas disease the Southern Cone of South America. We described morphometric traits and the natural variation of each leg segment. Different linear, size and shape variables of each component of the three right legs of fifth instar nymphs of T. infestans were analyzed using morphometric tools. We analyzed differentiation, variation and correlation for each segment across the fore-, mid and hind legs using different statistical approaches such as general linear model, canonical variates analysis, test of equality of coefficient of variation and partial least square analysis. We also analyzed variation and correlation between segments within each leg with partial least square and morphometric disparity analyses. Our results showed that the segments differed between legs, as general trends, the dimensions (length, width and/or size) were greater in the hind legs, smaller in the forelegs and intermediate in the mid ones. The femur and tibia (length and/or width) showed differences in morphometric variation between legs and the femur and tibia showed the highest levels of correlation between legs. On the other hand, in the fore- and mid legs, the femur (length or width) showed similar variation with tibia and tarsus lengths, but in the hind legs, the femur showed similar variation with all segments and not with the tibia length, and there were strong correlations between linear measurement within each leg. Our results suggest that the femur and tibia could play a determining role in the coordination between the legs that determines the walking pattern. Considering that these segments would also be linked to the specific function that each leg has, this study suggests a preponderant role of the femur and tibia in the walking locomotion of T. infestans.

A model for predicting the phenology of Philaenus spumarius.

The design and implementation of Philaenus spumarius control strategies can take advantage of properly calibrated models describing and predicting the phenology of vector populations in agroecosystems. We developed a temperature-driven physiological-based model based on the system of Kolmogorov partial differential equations to predict the phenological dynamics of P. spumarius. The model considers the initial physiological age distribution of eggs, the diapause termination process, and the development rate functions of post-diapausing eggs and nymphal stages, estimated from data collected in laboratory experiments and field surveys in Italy. The temperature threshold and cumulative degree days for egg diapause termination were estimated as 6.5°C and 120 DD, respectively. Preimaginal development rate functions exhibited lower thresholds ranging between 2.1 and 5.0°C, optimal temperatures between 26.6 and 28.3°C, and upper threshold between 33.0 and 35°C. The model correctly simulates the emergence of the 3rd, 4th, and 5th nymphal instars, key stages to target monitoring actions and control measures against P. spumarius. Precision in simulating the phenology of the 1st and 2nd nymphal stages was less satisfactory. The model is a useful rational decision tool to support scheduling monitoring and control actions against the late and most important nymphal stages of P. spumarius.

Effects of host plants on spotted lanternfly (Hemiptera: Fulgoridae) nymphal survival and development.

Spotted lanternfly, Lycorma delicatula (White), is an invasive planthopper from China, which was first detected in Berks County, PA, in 2014 and has since spread to adjacent states including New Jersey in 2018. Lycorma delicatula is a polyphagous species that gregariously feeds on over 172 known hosts. We investigated development on key host plants Ailanthus altissima (Miller) (Sapindales: Simaroubaceae), Juglans nigra (L.) (Fagales: Juglandaceae), Acer rubrum (L.) (Sapindales: Sapindaceae), and Vitis vinifera (L.) (Vitales: Vitaceae) for each instar to elucidate potential host use throughout the season and target monitoring efforts. Our study indicated significant differences in survivorship and time spent in each nymphal life stage between host plants. We applied a host suitability index as a function of survivorship and development for each host plant and instar, which indicated A. altissima and J. nigra as suitable hosts for all 4 nymphal instars. Vitis vinifera was highly suitable for first and second instars but had low indices for the third and fourth instars, although suitability of V. vinifera may have varied based on variety and age of the vine. Lycorma delicatula nymphs had the lowest survivorship and longest development time on A. rubrum across all 4 life stages, despite this being a preferred oviposition host. Host had a significant effect on the morphometrics we measured within the first and second instars.

New finding of Bolbossus bervoetsi Gnezdilov et Bourgoin, 2016 (Hemiptera: Fulgoroidea: Issidae) in Baltic amber, with description of a female and fifth instar nymph

New material on the planthopper species, Bolbossus bervoetsi Gnezdilov et Bourgoin, 2016 (Issidae, Issinae, Parahiraciini), originally described more than 100 years ago based on an adult of unknown sex from the Baltic amber, is redescribed and illustrated based on a female and fifth instar nymph recently discovered in the collection of the Natural History Museum of Denmark (Copenhagen).

Biology, morphometrics and mating behaviour of reduviid predator, Rhynocoris marginatus (Fab.)

A biology study of Rhynocoris marginatus revealed that eggs of this species had a length of 2.65mm and breadth of 0.72mm, incubated for 8.07 days with an average 89% hatching rate. Average durations of first to fifth nymphal instars were 9.3, 9.5, 8.25, 11.4 and 19.45 days, respectively. The size of nymphs increased with successive nymphal instars with the first instar of 2.02 mm in length and the fifth instar being 9.4 mm in length. The average nymphal developmental period was 57.9±2.5 days. Female adults were easily distinguishable due to their broader size measuring a length of 15.2 mm and abdominal width of 5.92 mm, while male adults measured 12.3 mm in length and 4.2 mm in abdominal width. The sex ratio was female-biased (0.89:1). Pre-oviposition, oviposition and post-oviposition period lasted for 12.9, 44.6 and 5.6 days, respectively. Fecundity was 279±48.2 with an average of 45.5 eggs per batch. Female adults survived (63.1 days) more than males (42.1 days). Total generation time was found longer in females (129.3 days) than in males (108.8 days). Keywords: Reduviid bug, Morphometrics, Rhynocoris marginatus

Endosymbiont and gut bacterial communities of the brown-banded cockroach, Supella longipalpa.

The brown-banded cockroach (Supella longipalpa) is a widespread nuisance and public health pest. Like the German cockroach (Blattella germanica), this species is adapted to the indoor biome and completes the entirety of its life cycle in human-built structures. Recently, understanding the contributions of commensal and symbiotic microbes to the biology of cockroach pests, as well as the applications of targeting these microbes for pest control, have garnered significant scientific interest. However, relative to B. germanica, the biology of S. longipalpa, including its microbial associations, is understudied. Therefore, the goal of the present study was to quantitatively examine and characterize both the endosymbiont and gut bacterial communities of S. longipalpa for the first time. To do so, bacterial 16S rRNA gene amplicon sequencing was conducted on DNA extracts from whole adult females and males, early instar nymphs, and late instar nymphs. The results demonstrate that the gut microbiome is dominated by two genera of bacteria known to have beneficial probiotic effects in other organisms, namely Lactobacillus and Akkermansia. Furthermore, our data show a significant effect of nymphal development on diversity and variation in the gut microbiome. Lastly, we reveal significant negative correlations between the two intracellular endosymbionts, Blattabacterium and Wolbachia, as well as between Blattabacterium and the gut microbiome, suggesting that Blattabacterium endosymbionts could directly or indirectly influence the composition of other bacterial populations. These findings have implications for understanding the adaptation of S. longipalpa to the indoor biome, its divergence from other indoor cockroach pest species such as B. germanica, the development of novel control approaches that target the microbiome, and fundamental insect-microbe interactions more broadly.

Effects of succession crops and soil tillage on suppressing the syndrome 'basses richesses' vector Pentastiridius leporinus in sugar beet.

Pentastiridius leporinus (Hemiptera: Cixiidae) is the most important vector of syndrome 'basses richesses' (SBR), a new disease that leads to severe economic losses in sugar beet. In this study, different soil tillage methods (ploughing and cultivator) and crops (winter wheat, spring wheat, maize and bare soil) following SBR-infested sugar beet were tested as potential management options in field trials. In the laboratory, the survival and development of first and third instar nymphs on wheat and maize was studied to further assess their suitability as host plants. In five out of seven field sites, reduced soil tillage had no effect on adult planthopper emergence compared to ploughing. In two sites, reduced tillage resulted in higher emergence rates. In nearly all field sites, up to 98.9% fewer emerging adults were detected in bare soil and maize, when compared to winter wheat. Under laboratory conditions, the lowest survival rate was found in first instar nymphs feeding on maize seedlings (4.2%), while 66.7% survived on wheat, over a period of 300 days. In contrast, 73.3% and 70% of third instar nymphs survived on wheat and maize over a period of 150 days. Soil tillage had little effect against Pentastiridius leporinus. Maize is a poor host for first instars but a suitable resource for third instar nymphs, the stage which encounters maize under field conditions. Hence, reductions in planthopper emergence in the field were likely caused by starvation due to the long host-free period between sugar beet harvest and the sowing of maize. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Management of Bemisia tabaci on vegetable crops using entomopathogens

The sweetpotato whitefly, Bemisia tabaci Gennadius, is a devastating insect pest on vegetable crops around the world. This pest causes significant damage by directly feeding on vegetables, excreting honeydew, inducing plant physiological disorders, and transmitting plant viruses. The combined direct and indirect damage to vegetable crops has led to substantial economic losses. The heavy reliance on chemical insecticides for whitefly control has led to considerable resistance to many insecticides in whitefly populations. Therefore, integrated pest management (IPM) that includes entomopathogens is considered as a sustainable and effective approach against B. tabaci. This review focuses on biological control of B. tabaci using entomopathogens, including entomopathogenic fungi (EPF), entomopathogenic nematodes (EPN), and entomopathogenic bacteria (EPB). Among them, EPF is the mostly explored group of entomopathogens for B. tabaci control. In particular, Beauveria bassiana (Balsamo-Crivelli) Vuillemin, Akanthomyces lecanii (Zimm.) Spatafora, Kepler and B. Shrestha, Cordyceps javanica (Frieder. & Bally) Kepler, B. Shrestha & Spatafora, and C. fumosorosea (Wize) Kepler, B. Shrestha & Spatafora are the most commonly used EPF species for whitefly control. The control efficacy of EPN against B. tabaci varies with strains/species and concentrations of the EPN, whitefly nymphal instars, host plants, and environmental conditions. Most research on evaluating the virulence of various EPB isolates against whiteflies has been conducted in the laboratory. Entomopathogens offer a promising strategy for whitefly management in vegetables. This review discusses research updates on the three entomopathogen groups for whitefly control, barriers in broad adoption by vegetable growers, and future directions.

A review of the genus Neogreenia MacGillivray (Hemiptera: Coccomorpha: Qinococcidae) with descriptions of two new species.

The species of Neogreenia MacGillivray (Hemiptera: Coccomorpha: Qinococcidae) are reviewed. The genus is distributed in the Oriental and Palaearctic Regions and now contains seven species. The present study provides updated generic descriptions of all the developmental stages and a brief account of the biology and life cycle of Neogreenia. The genotype, Neogreenia zeylanica (Green, 1896), is redescribed. The following are described and illustrated for the first time: the second-instar nymph, third-instar female, and male third-instar nymph and pupa of N. zizyphi Tang; the second-instar nymph of N. lonicera Wu & Nan; and the second-instar nymph of N. sophorica Wu. Two new species are described and illustrated: Neogreenia ficus Zheng & Wu, sp. n. based on the adult female and Neogreenia tangi Zheng & Wu, sp. n. based on all female instars. These new species bring the total number of described species of Neogreenia to seven. An identification key to all the developmental stages of Neogreenia, and identification keys to species based on adult females and available nymphal instars are provided.

RNAi-mediated silencing of the neverland gene inhibits molting in the migratory locust, Locusta migratoria

7-dehydrocholesterol (7-DHC) is a key intermediate product used for biosynthesis of molting hormone. This is achieved through a series of hydroxylation reactions catalyzed by the Halloween family of cytochrome P450s. Neverland is an enzyme catalyzes the first reaction of the ecdysteroidogenic pathway, which converts dietary cholesterol into 7-DHC. However, research on the physiological function of neverland in orthopteran insects is lacking. In this study, neverland from Locusta migratoria (LmNvd) was cloned and analyzed. LmNvd was mainly expressed in the prothoracic gland and highly expressed on days 6 and 7 of fifth instar nymphs. RNAi-mediated silencing of LmNvd resulted in serious molting delays and abnormal phenotypes, which could be rescued by 7-DHC and 20-hydroxyecdysone supplementation. Hematoxylin and eosin staining results showed that RNAi-mediated silencing of LmNvd disturbed the molting process by both promoting the synthesis of new cuticle and suppressing the degradation of the old cuticle. Quantitative real-time PCR results suggested that the mRNA expression of E75 early gene and chitinase 5 gene decreased and that of chitin synthase 1 gene was markedly upregulated after knockdown of LmNvd. Our results suggest that LmNvd participates in the biosynthesis process of molting hormone, which is involved in regulating chitin synthesis and degradation in molting cycles.

Phenology model development for Neodryinus typhlocybae: Evaluation of phenological synchrony with its host, Metcalfa pruinosa

The invasive species Metcalfa pruinosa has inflicted significant economic losses in various European and Asian regions. To combat this pest, the parasitoid wasp Neodryinus typhlocybae has been effectively introduced in Europe. Despite its success, research on the field occurrence patterns of N. typhlocybae, particularly its phenology, remains scarce. This study aims to develop a degree-day model for predicting the adult emergence of N. typhlocybae from overwintering cocoons and to assess the phenological synchrony between N. typhlocybae adults and the nymphal stages of M. pruinosa in Korea. In this study, we estimated the thermal parameters of N. typhlocybae under field temperatures and six constant temperatures (13.92, 17.71, 18.53, 20.53, 22.78, and 24.03 °C) conditions. The lower developmental temperature was estimated using the values of the coefficient of variation for the cumulative degree days of emerged individual adults. The estimated lower developmental threshold temperature was 12.3 °C. With this developmental threshold, a degree-day model was developed, and this model well-predicted emergence in field conditions. By simulating this developed model with the actual occurrence of the nymphal stages of its host, M. pruinosa, adult wasp emergence was estimated to be 1.5 weeks later than the first instar nymph of the host but faster than other nymphal stages of M. pruinosa. Thus, the findings in this study would be helpful in determining the possibility of establishing N. typhlocybae and improving the management efficiency of M. pruinosa.

Effects of temperature on the survival of spotted lanternfly active life stages when held without food

Abstract Spotted lanternfly, Lycorma delicatula White (Hemiptera: Fulgoridae), is an invasive Southeast Asian planthopper that was recently introduced into the eastern United States and spreads along human transportation corridors by ‘hitch‐hiking’ on vehicles and cargo. To better understand the risk of establishment when mobile life stages are moved, it is critical to know how long spotted lanternfly mobile life stages will survive without food and water under different temperatures. This work reports on spotted lanternfly first, second, and third instar nymphal and adult survival without food over the 10–30°C temperature range. Survival time without food declined exponentially as temperature increased for all life stages of spotted lanternfly that were evaluated. At temperatures <30°C, first instar nymphs survived longer than second or third instar individuals. Female adults survived about 1 day longer than male adults at all but 10 and 25°C. Without food, 99% of all adults of both sexes are predicted to be dead in less than a week over the temperature range evaluated. First instars, which were the smallest, survived the longest and their survival exponentially decreased as temperature increased. This suggests that more attention to first instar movement may be warranted. The data presented here will provide a basis for assessing the risk of survival of transported spotted lanternfly active life stages along various pathways.

Predator-Prey Interaction Between Xylocoris sordidus (Hemiptera: Anthocoridae) and Enneothrips enigmaticus (Thysanoptera: Thripidae).

The peanut thrips, Enneothrips enigmaticus (Thysanoptera: Thrypidae), is an important pest of the peanut (Arachis hypogaea) in South America. Due to concerns about the environment and human health induced by the extensive use of pesticides in the management control of pests, environmentally and friendlier tactics must be targeted. Thus, this study investigates, for the first time, the behavior of Xylocoris sordidus (Hemiptera: Anthocoridae) as a biological control agent for E. enigmaticus. The methodology included no-choice tests to assess whether the predation rate varies according to the developmental stage of the prey, as well as the predator's developmental stage with the highest predation capacity. Additionally, an analysis of the functional response of adult and 5th instar nymphs of X. sordidus exposed to different densities of E. enigmaticus nymphs (1, 2, 4, 8, 16, and 32) was conducted. The results confirm the predation of peanut thrips by X. sordidus, with a higher predation rate in the nymphal stages of the prey. There was no difference in predation capacity between predator nymphs and adults, and exhibiting a type II functional response. Therefore, the potential of X. sordidus as a biological control agent for E. enigmaticus is confirmed, showing the importance of adopting measures to preserve this predator in peanut crops.

The inappropriate application of imidacloprid destroys the ability of predatory natural enemies to control pests in the food chain: A case study of the feeding behavior of Orius similis on Frankliniella occidentalis

Insecticides are an indispensable and important tool for agricultural production. However, the inappropriate application of insecticides can cause damage to the food chain and ecosystem. Orius similis is an important predatory and natural enemy of Frankliniella occidentalis. Imidacloprid is widely used to control pests, but will inevitably exert adverse effects on O. similis. In order to determine the effect of different imidacloprid treatments on the ability of O. similis to prey on the 2nd-instar nymphs of F. occidentalis, we determined the toxicity and predation of imidacloprid on different stages of O. similis under contact and ingestion treatments. In addition, we used the Holling disc equation to evaluate the ability of O. similis to search and exhibit predatory activity following contact and ingestion treatments. Analysis showed that the highest LC10 and LC20 values for imidacloprid contact and ingestion toxicity treatment were 17.06 mg/L and 23.74 mg/L, respectively. Both imidacloprid treatments led toa reduction in the predatory of O. similis on prey. The functional responses of the 3rd to 5th instar nymphs, along with female and male O. similis adults to the 2nd-instar nymphs of F. occidentalis were consistent with the Holling type II response following contact and ingestion with imidacloprid. However, following imidacloprid treatment, the handing time (Th) of O. similis with single F. occidentalis was prolonged and the instantaneous attack rate (a) was reduced after imidacloprid treatment. The predatory capacity (a/Th) of female O. similis adults when treated with the LC10 concentration of imidacloprid by ingestion was 52.85; this was lower than that of the LC10 concentration of imidacloprid in the contact treatment (57.67). The extent of predation of O. similis on the 2nd-instar nymphs of F. occidentalis was positively correlated with prey density, although the search effect was negatively correlated with prey density. The most extensive search effect was exhibited by adult O. similis females. Simulations with the Hessell-Varley interference model showed that an increase in the number of O. similis would reduce search efficiency regardless of whether they were treated with imidacloprid or not. Thus, O. similis, especially female adults, exhibited strong potential for controlling the 2nd-instar nymphs of F. occidentalis. The toxicity of ingestion following treatment with the same concentration of imidacloprid in O. similis was greater than that of contact treatment. When using O. similis to control F. occidentalis in the field, we should increase the number of female adults released, and prolong the interval between imidacloprid treatment and O. similis exposure. This strategy will improve the control ability of O. similis, coordinate both chemical and biological control, reduce the impact of pesticides on the environment, and improve the efficiency of agricultural production.

Aleurotrachelus trachoides Back’s (Hemiptera: Aleyrodidae) preference on different host plants

One invasive pest that has affected vegetable crops is the whitefly. Aleurotrachelus trachoides Back is a newly discovered whitefly pest that affects a number of horticultural crops. This study assessed Aleurotrachelus trachoides Back.’s preference (antixenosis) for eggplant, tomato, chili, okra, and cucumber. It also analyzed at the relationship between the quantity of eggs and early instar nymphs per plant and the morphology of the leaves (trichome, epidermis, palisade, and thickness). In January 2018, A. trachoides was taken from the Bambu Kuning Greenhouse at the National University in Jakarta. This study was carried out in June and July of 2018 at the Cikabayan Greenhouse, IPB University, Bogor, using a randomized complete block design with three replications (@2 plants/genotype). Eggplant (cv. Ratih Ungu) had the highest amount of A. trachoides eggs and early instar nymphs, followed by okra (cv. Nayla), tomato (cv. New Mutiara), cucumber (cv. Maestro), chili (cv. Kastilo), and chili (cv. Yuni). A. trachoides had a preference for tomatoes, chilies, and eggplant (Solanaceae family). The number of eggs and early instar nymphs per plant did not correlate with the different host plants’ leaf morphology. A. trachoides favored the genotype on chilies that had more non-glandular trichomes.

Bacillus thuringiensis translocation in citrus scion/rootstock combinations and binding of cry toxins with the Asian citrus psyllid gut receptors

Bacillus thuringiensis (Bt) can be effective in controlling insect pests either in spray products or by their toxins expressed in transgenic crops. The discovery of Bt as endophytic in citrus opened new perspectives for the control of Diaphorina citri Kuwayama, the vector of the bacteria Candidatus Liberibacter spp. associated with Huanglongbing. In this study, the endophytic translocation of Bt in citrus seedlings (small and large plants) and in different scion-rootstock combinations were investigated. We also assessed the lethal concentration of D. citri nymphs caused by systemic Bt in citrus and, moreover, the binding of Cry toxins with the Asian citrus psyllid (ACP) gut receptors. Endophytic translocation of Bt in citrus seedlings and nursery trees was confirmed by colony isolation, PCR detection, and Btk-GFP microscopy analyses, which demonstrated that, after Bt inoculation into the substrate, the bacteria enter through lateral root emergence sites and are localized in stem xylem vessel elements. Mean lethal concentrations for D. citri third instar nymphs were 4.92 × 104 and 2.19 × 104 spores mL−1 for S1450 and S1302 strains, respectively. Nymphal mortality induced by the bacteria was higher in citrus seedlings than in citrus nursery trees. All Cry-toxins tested were able to bind to D. citri brush border membrane vesicles, suggesting the potential pathogenicity of Bt strains against psyllid. This study clearly demonstrates the penetration and Bt translocation in the xylem of small and large citrus plants and the potential of the bacteria to cause ACP nymphs mortality that fed on shoots from Bt-treated citrus.

Endosymbiotic Fungal Diversity and Dynamics of the Brown Planthopper across Developmental Stages, Tissues, and Sexes Revealed Using Circular Consensus Sequencing.

Endosymbiotic fungi play an important role in the growth and development of insects. Understanding the endosymbiont communities hosted by the brown planthopper (BPH; Nilaparvata lugens Stål), the most destructive pest in rice, is a prerequisite for controlling BPH rice infestations. However, the endosymbiont diversity and dynamics of the BPH remain poorly studied. Here, we used circular consensus sequencing (CCS) to obtain 87,131 OTUs (operational taxonomic units), which annotated 730 species of endosymbiotic fungi in the various developmental stages and tissues. We found that three yeast-like symbionts (YLSs), Polycephalomyces prolificus, Ophiocordyceps heteropoda, and Hirsutella proturicola, were dominant in almost all samples, which was especially pronounced in instar nymphs 4-5, female adults, and the fat bodies of female and male adult BPH. Interestingly, honeydew as the only in vitro sample had a unique community structure. Various diversity indices might indicate the different activity of endosymbionts in these stages and tissues. The biomarkers analyzed using LEfSe suggested some special functions of samples at different developmental stages of growth and the active functions of specific tissues in different sexes. Finally, we found that the incidence of occurrence of three species of Malassezia and Fusarium sp. was higher in males than in females in all comparison groups. In summary, our study provides a comprehensive survey of symbiotic fungi in the BPH, which complements the previous research on YLSs. These results offer new theoretical insights and practical implications for novel pest management strategies to understand the BPH-microbe symbiosis and devise effective pest control strategies.

Wing expansion functional analysis of ion transport peptide gene in Sogatella furcifera (Horváth) (Hemiptera: Delphacidae)

Ion transport peptide (ITP), a superfamily of arthropod neuropeptides, serves a crucial role in regulating various physiological processes such as diuresis, ecdysis behavior, and wing expansion. However, the molecular characteristics, expression profile, and role of ITP in Sogatella furcifera are poorly understood. To elucidate the characteristics and biological function of ITP in S. furcifera, we employed reverse transcription-polymerase chain reaction (RT-PCR) and RNA interference (RNAi) methods. The identified SfITP gene encodes 117 amino acids. The expression of SfITP gradually increased followed the formation of 3-day-old of 5th instar nymph, peaking initially at 40 min after eclosion, and reaching another peak 24 h after eclosion, with particularly high expression levels in thorax and wing tissues. Notably, SfITP RNAi in 3rd instar nymphs of S. furcifera significantly inhibited the transcript levels of SfITP, resulting in 55% mortality and 78% wing deformity. These findings suggests that SfITP is involved in the regulation of wing expansion in S. furcifera, providing insights into the regulation of insect wing expansion and contributing to the molecular understanding of this process.