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Symbiont-mediated nutritional mutualisms can contribute to the host fitness of insects, especially for those that feed exclusively on nutritionally unbalanced diets. Here, we elucidate the importance of B group vitamins in the association of endosymbiotic bacteria Wolbachia with two plant-sap feeding insects, the small brown planthopper, Laodelphax striatellus (Fallén), and the brown planthopper, Nilaparvata lugens (Stål). Infected planthoppers of both species laid more eggs than uninfected planthoppers, while the experimental transfer of Wolbachia into uninfected lines of one planthopper species rescued this fecundity deficit. The genomic analysis showed that Wolbachia strains from the two planthopper species encoded complete biosynthesis operons for biotin and riboflavin, while a metabolic analysis revealed that Wolbachia -infected planthoppers of both species had higher titers of biotin and riboflavin. Furthermore, experimental supplementation of food with a mixture of biotin and riboflavin recovered the fecundity deficit of Wolbachia -uninfected planthoppers. In addition, comparative genomic analysis suggested that the riboflavin synthesis genes are conserved among Wolbachia supergroups. Biotin operons are rare in Wolbachia , and those described share a recent ancestor that may have been horizontally transferred from Cardinium bacteria. Our research demonstrates a type of mutualism that involves a facultative interaction between Wolbachia and plant-sap feeding insects involving vitamin Bs.

Two new planthopper species of the family Issidae, tribe Sarimini are described from Central Vietnam. Dactylissus sinuatus Constant & Pham, sp. nov . from Hon Ba Nature Reserve in Khanh Hoa Province, represents the second species of the genus Dactylissus Gnezdilov & Bourgoin, 2014 so far known only from Hon Ba, and Tetrichina honbana Constant & Pham, sp. nov . from Hon Ba Nature Reserve, Nui Chua National Park in Khanh Hoa Province and Ta Kou Nature Reserve in Binh Thuan Province, represents the first record of the genus Tetrichina Chang & Chen, 2020 in Vietnam. Illustrations of habitus and terminalia of the new species are given as well as a distribution map and photographs of live specimens and their habitat.

The new genus is described to accommodate a new species, from Pu Mat National Park in Vietnam. The new genus is placed in the subtribe Parahiraciina of the Parahiraciini. It is compared with the genera Constant, 2021, Che, Zhang et Wang, 2012, Che, Zhang et Wang, 2011, and Che, Zhang et Wang, 2020 with which it shares possessing an elongate head. Illustrations of habitus, details, and male genitalia are given as well as a distribution map and photographs of the habitat. Constant, 2021 is recorded for the first time from Vietnam, Pu Luong National Park; living specimens and habitat are illustrated, and the distribution map updated. The Parahiraciini fauna of Vietnam now comprises 14 species belonging to 11 genera.

Food quality is a critical environmental condition that impacts an animal’s growth and development. Many insects facing this challenge have evolved a phenotypically plastic, adaptive response. For example, many species of insect exhibit facultative wing growth, which reflects a physiological and evolutionary trade-off between dispersal and reproduction, triggered by environmental conditions. What the environmental cues are and how they are transduced to produce these alternative forms, and their associated ecological shift from dispersal to reproduction, remains an important unsolved problem in evolutionary ecology. In this study, we investigated the role that host quality has on the induction of wing development in a wing polyphenic insect exhibiting strong tradeoffs in investment between dispersal and reproduction, the brown planthopper, a serious rice pest in Asia. As rice plants grow, the short-winged brown planthopper dominates the population, but a shift occurs as the plants mature and senesce in the field such that long-winged brown planthoppers emerge and migrate. It remains unknown how changes in the rice plant induce development of the long-winged morph, despite recent discoveries on the role of the insulin and JNK signaling pathways in wing development. We found that by mimicking the glucose concentration of senescing rice plants, we significantly increased the proportion of long-winged female planthoppers. The effects of glucose on wing morph are additive with previously described effects of density. Our results show that host quality both directly regulates phenotypic plasticity and interacts with other factors such as density to produce the appropriate phenotype for specific environmental conditions.

Non-retroviral endogenous viral elements (nrEVEs) are widely dispersed throughout the genomes of eukaryotes. Although nrEVEs are known to be involved in host antiviral immunity, it remains an open question whether they can be domesticated as functional proteins to serve cellular innovations in arthropods. In this study, we found that endogenous toti-like viral elements (ToEVEs) are ubiquitously integrated into the genomes of three planthopper species, with highly variable distributions and polymorphism levels in planthopper populations. Three ToEVEs display exon‒intron structures and active transcription, suggesting that they might have been domesticated by planthoppers. CRISPR/Cas9 experiments revealed that one ToEVE in Nilaparvata lugens , NlToEVE14, has been co-opted by its host and plays essential roles in planthopper development and fecundity. Large-scale analysis of ToEVEs in arthropod genomes indicated that the number of arthropod nrEVEs is currently underestimated and that they may contribute to the functional diversity of arthropod genes. Non-retroviral endogenous viral elements are widely dispersed in eukaryotic genomes, but their functions remain largely unknown. Here, Huang et al show that one such element in planthoppers has been co-opted and contributes to insect fitness..

Insect wing polyphenism is characterized by its ability to produce two or more distinct wing morphs from a single genotype in response to changing environments. However, the molecular basis of this phenomenon remains poorly understood. Here, we identified a zinc finger homeodomain transcription factor Zfh1 that acts as an upstream regulator for the development of long-winged (LW) or shorted-winged (SW) morphs in planthoppers. Knockdown of Zfh1 directs SW-destined nymphs to develop into LW morphs by down-regulating the transcriptional level of FoxO , a prominent downstream effector of the insulin/IGF signaling (IIS) pathway. The balance between transcriptional regulation via the Zfh1-FoxO cascade and post-translational regulation via the IIS-FoxO cascade provides a flexible regulatory mechanism for the development of alternative wing morphs. These findings help us understand how phenotypic diversity is generated by altering the activity of conserved proteins, and provide an extended framework for the evolution of wing morphological diversity in insects. The molecular mechanisms underlying wing polyphenism remain poorly understood. Here the authors use plant hoppers to show that the development of long and short wing morphs is balanced by the relative activities of the Zfh1-FoxO and insulin signaling cascades.

The tropical bat Mops plicatus feeds primarily on planthoppers, a major pest for rice farmers in Southeast Asia. This bat may help limit the spread of planthoppers by feeding on wind-dispersed individuals at high altitudes, providing an important ecosystem service. However, its foraging behavior during peak planthopper activity remains poorly understood. Therefore, we examined the three-dimensional foraging behavior of M. plicatus using miniaturized Global Positioning System loggers during peak emergence of planthoppers. We predicted that bats would spend most foraging time at high altitudes (i.e., > 110 m above ground), and use relatively large foraging ranges. Furthermore, we predicted that low-altitude flights would occur in paddy fields and high-altitude flights above forested sites on mountain ridges. Six of the 11 tracked bats used large foraging areas, covering between 40 to 1,740 km 2 during a single night. The median distance bats traveled per foraging trip was 60 km (range 27–217 km), with a median maximum distance from the cave roost of 26 km (range 13–95 km). Bats flew at a median altitude of 146 m above ground, yet occasionally reached more than 1,600 m above ground. Our results confirmed that M. plicatus foraged primarily at high altitudes for about 57% of their time. They preferred paddy fields and forests while avoiding water bodies. With its high-altitude flights and preference for planthoppers as prey, M. plicatus could help limit the spread of a major rice pest in Southeast Asia. Protecting this bat species could help support rice harvests throughout the region.

Biological control services of agroecosystems depend on the functional diversity of species traits. However, the relationship between arthropod traits and landscape heterogeneity is still poorly understood, especially in tropical rice agroecosystems, which harbor a high diversity of often specialized species. We investigated how landscape heterogeneity, measured by three metrics of landscape composition and configuration, influenced body size, functional group composition, dispersal ability, and vertical distribution of rice arthropods in the Philippines. We found that landscape composition and configuration acted to filter arthropod traits in tropical rice agroecosystems. Landscape diversity and rice habitat fragmentation were the two main gradients influencing rice-arthropod traits, indicating that different rice arthropods have distinct habitat requirements. Whereas small parasitoids and species mostly present in the rice canopy were favored in landscapes with high compositional heterogeneity, predators and medium-sized species occupying the base of the rice plant, including planthoppers, mostly occurred in highly fragmented rice habitats. We demonstrate the importance of landscape heterogeneity as an ecological filter for rice arthropods, identifying how the different components of landscape heterogeneity selected for or against specific functional traits. However, the contrasting effects of landscape parameters on different groups of natural enemies indicate that not all beneficial rice arthropods can be promoted at the same time when using a single land management strategy. Increasing compositional heterogeneity in rice landscapes can promote parasitoids but may also negatively affect predators. Future research should focus on identifying tradeoffs between fragmented rice habitats and structurally diverse landscapes to maximize the presence of multiple groups of beneficial arthropods.

Strictly heritable endosymbiotic bacteria that provide limiting nutrients to sap-sucking hemipteran insects are known for their highly reduced genomes conserved in organization and function. Here, we show how in ancestral endosymbionts of planthoppers, Sulcia and Vidania , which have been gradually losing genes during ~263 my of co-diversification with hosts, co-infections by additional microbes and host ecological switches coincided with more dramatic genomic changes. At its extremes, this has resulted in the smallest non-organellar bacterial genomes known, at barely 50-52 kb. Such minuscule Vidania genomes evolved convergently in two planthopper superfamilies, and are strikingly similar in gene contents, including the ability to produce a single amino acid (phenylalanine) for the host. Losing many additional cell-function genes places them very close to organelles of symbiotic origin in the level of host dependence, further blurring the bacteria-organelle boundary. Symbiotic bacteria can have exceedingly small genomes. This study finds that ancient bacterial symbionts of planthoppers have repeatedly evolved the smallest known genomes, losing most biosynthetic functions, revealing how extreme genome reduction shapes life at the edge of cellular complexity.

Little is known about the mitochondrial genome of the family Eurybrachidae, with only two species sequenced. This study added one more mitogenome of Loxocephala sichuanensis in this family. The mitochondrial genome length of this species was 15,605 bp, consisting of 37 genes: 13 PCGs, 2 rRNAs, 22 tRNAs, and a control region. An unusually high A + T content, reaching 94.3% at the third codon position of 13 PCGs in Loxocephala , was found in Eurybrachidae, which was the highest among all planthoppers, especially on N-strand. Three tandem repeat regions were detected in the control region. Phylogenetic analyses based on complete mitochondrial genome sequences from 145 species (encompassing 18 planthopper families and 135 species in Fulgoromorpha as ingroup, and 6 other non-planthopper families in Auchenorrhyncha as outgroup) were conducted. Six datasets (PCG123R24, PCG123R2, PCG123, PCG12R24, PCG12R2, PCG12) were established to investigate the influence of 22 tRNAs and the third codon of the 13 PCGs of mitogenome for phylogeny analyses. Both Maximum likelihood and Bayesian trees supported the monophyly of the superfamilies Delphacoidea and Fulgoroidea. Delphacoidea, consisting of Cixiidae and Delphacidae as sister group, was in the basal position of Fulgoromorpha. In Fulgoroidea, the families Meenoplidae and Kinnaridae, Dictyopharidae and Fulgoridae, Acanaloniidae and Tropiduchidae were sister groups which were strongly supported. Caliscelidae was close to the sister group Lophopidae with Eurybrachidae. The four families Flatidae, Nogodinidae, Ricaniidae and Issidae were closely related. The position of Tettigometridae was uncertain. Derbidae and Achilidae form a sister group when 22 tRNAs were included in the phylogeny. The joining of the tRNA sequences of mitochondrial genome enhanced the stability of family-level nodes and adjusted some phylogenetic positions, highlighting the significant role of joining tRNAs in phylogenetic analyses. Including or excluding the third codon position of 13 PCGs generally did not affect the overall phylogenetic structures of Fulgoromorpha.