Artemisia frigida (Asterales: Asteraceae) Improves the Growth of Grasshopper Calliptamus abbreviatus and Increases the Risk of Damaging Populations

The grasshopper Calliptamus abbreviatus Ikonn is a significant pest species distributed across the northern Asian grasslands. Grasshopper plagues often result in significant loss to plant biomass and subsequent deterioration of grass quality that leads to economic depletion. To better understand the close relationship between C. abbreviatus and host plant species, a 2-yr study was conducted. Results showed that the relative density of C. abbreviatus was positively correlated with aboveground biomass of the plant Artemisia frigida. We hypothesized that A. frigida, the most favorable food resource, was optimal for growth performance and that the presence of this plant species led to C. abbreviatus plagues. A controlled feeding trial showed that C. abbreviatus had better growth performance (i.e., survival rate, body mass, and growth rate) when fed on A. frigida and this host was preferred over other plant species since the consumption and food utilization efficiency on plant was comparatively greater. These results were consistent with the distribution of C. abbreviatus in the grassland and suggested that the presence of A. frigida significantly improved C. abbreviatus growth performance. These findings will be useful for designing improved pest management strategies in response to grassland vegetation succession due to grazing, climate change, or human interference.

Host Range and Effects of Plant Species on Preference and Fitness of Tuta absoluta (Lepidoptera: Gelechiidae)

Tuta absoluta (Meyrick) is one of the most devastating pests of tomato in both open field and greenhouse production settings that significantly reduce yield and quality of the fruit. Being a new invasive pest, information on the pest bio-ecology, including host-rage and effects of plant species on its various fitness traits are virtually lacking. This study involved a field survey to establish the realized host range and laboratory experiments to evaluate the preference for, and fitness effects of T. absoluta on different plant species. In the field, T. absoluta was recovered from only four solanaceous plant species: tomato (Solanum lycopersicum L.), eggplant (S. melongena L.), black nightshade (S. nigrum L.), and gubbain (S. dubium Fr.). In choice and no-choice tests, tomato was the most preferred host of T. absoluta having the highest number of eggs deposited, followed by black nightshade, French bean Phaseolus vulgaris L., and chilli pepper Capsicum frutescens. Larvae developed quickest on tomato followed by black nightshade and French bean. The percentage survival to adulthood was significantly higher on tomato, compared to survival on black nightshade and French bean. Rearing of T. absoluta on tomato or black nightshade had no significant effect on pupal mass and length as well as adult size for both sexes. Fecundity and longevity, as well as oviposition preference of T. absoluta, were not affected by rearing on different plants. These findings confirm the oligophagous nature of the pest with high preference to tomato.

Biology, Ecology, and Management of Erthesina fullo (Hemiptera: Pentatomidae): A Review

The yellow spotted stink bug (YSSB), Erthesina fullo Thunberg, is one of the most widely distributed phytophagous insect pests in Asia. YSSB is highly polyphagous and in China it feeds on over 57 host plants in 29 families, including some economically important fruit crops such as kiwifruit, pear, peach, apple, and pomegranate. With a primarily r-selected life history strategy, reproductive diapause, aggregation behavior, wide host range, high dispersal capacity, and close association with human-modified ecosystems, YSSB is a potentially invasive species that poses significant biosecurity threats to other countries outside its native range. This review summarizes basic and applied knowledge on the biology, ecology, and management of YSSB in China, with specific emphasis on its life history, host range, damage and impacts on economically important horticulture crops, and integrated pest management (IPM) approaches. The insights from the Chinese literature on this pest will help the countries outside its native range to conduct appropriate biosecurity risk assessments, develop a sound surveillance program, and develop an emergency response plan before its invasion of new geographic areas.

Host Plant and Antibiotic Effects on Scent Bouquet Composition of Anastrepha ludens and Anastrepha obliqua Calling Males, Two Polyphagous Tephritid Pests

In insects, the quality of sex pheromones plays a critical role in mating success and can be determined by the ability of larvae/adults to accrue chemical precursors. We tested the host-quality-effect hypothesis by analyzing the chemical composition of scent bouquets emitted by calling males of two polyphagous tephritid species (Anastrephaludens and A. obliqua) that originated from 13 fruit species representing diverse plant families. In A. ludens, we worked with an ancestral host (Rutaceae), nine exotic ones (Rutaceae, Anacardiaceae, Rosaceae, Solanaceae, Lythraceae), and two species never attacked in nature but that represent candidates for host-range expansion (Solanaceae, Myrtaceae). In A. obliqua, we tested an ancestral, a native, and an exotic host (Anacardiaceae), one occasional (Myrtaceae), and one fruit never attacked in nature (Solanaceae). We identified a core scent bouquet and significant variation in the bouquet’s composition depending on the fruit the larvae developed in. We also tested the possible microbial role on the scent bouquet by treating adults with antibiotics, finding a significant effect on quantity but not composition. We dwell on plasticity to partially explain our results and discuss the influence hosts could have on male competitiveness driven by variations in scent bouquet composition and how this could impact insect sterile technique programs.

Her Majesty's Desert Throne: The Ecology of Queen Butterfly Oviposition on Mojave Milkweed Host Plants

Butterfly-host plant relationships can inform our understanding of ecological and trophic interactions that contribute to ecosystem function, resiliency, and services. The ecology of danaid-milkweed (Apocynaceae) host plant interactions has been studied in several biomes but is neglected in deserts. Our objective was to determine effects of plant traits, seasonality, and landscape-level host plant availability on selection of Mojave milkweed (Asclepias nyctaginifolia A. Gray) by ovipositing monarch butterflies (Danaus plexippus plexippus) and queen butterflies (Danaus gilippus thersippus) in the Californian Mojave Desert. We surveyed all known Mojave milkweed locations in the Ivanpah Valley, California (n = 419) during early, mid-, and late spring in 2017. For each survey, we counted monarch and queen butterfly eggs on each Mojave milkweed plant. We also measured canopy cover, height, volume, and reproductive stage of each Mojave milkweed plant. We counted a total of 276 queen butterfly eggs and zero monarch butterfly eggs on Mojave milkweed host plants. We determined that count of queen butterfly eggs significantly increased with increasing Mojave milkweed canopy cover. Additionally, count of queen butterfly eggs was: (1) greater on adult Mojave milkweed plants than on juvenile and seedling plants and greater on juvenile Mojave milkweed plants than on seedling plants; and (2) greater during early spring than mid-spring-we recorded no eggs during late spring. Based on aggregation indices, queen butterfly eggs occurred on Mojave milkweed plants in a nonrandom, clustered pattern throughout the Ivanpah Valley. We provide the first evidence of trophic interactions between queen butterflies and Mojave milkweed at multiple spatial scales in the Mojave Desert, suggesting that conservation and management practices for both species should be implemented concurrently. Given its role as an herbivore, pollinator and prey, the queen butterfly may serve as a model organism for understanding effects of anthropogenic disturbance (e.g., solar energy development) on "bottom-up" and trophic interactions among soils, plants and animals in desert ecosystems.

Host Plants Influence the Symbiont Diversity of Eriosomatinae (Hemiptera: Aphididae)

Eriosomatinae is a particular aphid group with typically heteroecious holocyclic life cycle, exhibiting strong primary host plant specialization and inducing galls on primary host plants. Aphids are frequently associated with bacterial symbionts, which can play fundamental roles in the ecology and evolution of their host aphids. However, the bacterial communities in Eriosomatinae are poorly known. In the present study, using high-throughput sequencing of the bacterial 16S ribosomal RNA gene, we surveyed the bacterial flora of eriosomatines and explored the associations between symbiont diversity and aphid relatedness, aphid host plant and geographical distribution. The microbiota of Eriosomatinae is dominated by the heritable primary endosymbiont Buchnera and several facultative symbionts. The primary endosymbiont Buchnera is expectedly the most abundant symbiont across all species. Six facultative symbionts were identified. Regiella was the most commonly identified facultative symbiont, and multiple infections of facultative symbionts were detected in the majority of the samples. Ordination analyses and statistical tests show that the symbiont community of aphids feeding on plants from the family Ulmaceae were distinguishable from aphids feeding on other host plants. Species in Eriosomatinae feeding on different plants are likely to carry different symbiont compositions. The symbiont distributions seem to be not related to taxonomic distance and geographical distance. Our findings suggest that host plants can affect symbiont maintenance, and will improve our understanding of the interactions between aphids, their symbionts and ecological conditions.

Transcription and Activity of Digestive Enzymes of Nezara viridula Maintained on Different Plant Diets

Nezara viridula is a polyphagous stink bug that feeds on crops of economic importance such as corn, soybean and cotton. To increase understanding of the ability of this pest insect to feed on such diverse cropping systems, we analyzed the impact of an exclusive diet of corn or green bean on the enzymatic activity and transcriptomic profile of digestive enzymes. Growth rate and survival were reduced when insects were reared exclusively on green bean compared to corn. However, the overall protease and nuclease activity profiles were comparable between the two treatments. Distinct differences in inhibitor sensitivity and activity were seen in some cases, particularly for serine proteases in some regions of the midgut. The transcription profiles from N. viridula fed on corn versus green bean were distinct on principal component analysis of RNA-seq data. While specific transcripts differentially transcribed according to diet and across several tissues were identified, a large number of these transcripts remain unannotated. Further annotation for identification of these genes will be important for improved understanding of the remarkable polyphagy of N. viridula.

Taxonomic study of the genus Townesia Ozols (Hymenoptera, Ichneumonidae, Pimplinae) with description of a new species from China and a key to world species

Five species of the genus Townesia Ozols are reported. One, Townesiasulcata Sheng & Li, sp. nov. collected from Liaoning province, China, is new to science. In addition, digital images and a taxonomic key to the all species of Townesia are presented.

The Cassidinae beetles of Longnan County (Jiangxi, China): overview and community composition

There are few reports on the community composition and diversity pattern of the Cassidinae species of China. Compared to the neighbouring provinces of Guangdong, Fujian and Zhejiang, the Cassidinae richness in Jiangxi Province is under-reported. Longnan City, a biodiversity hotspot in Jiangxi Province, was chosen to obtain the first overview of the Cassidinae beetles. The sample coverage curves for the three sample sites reached an asymptote which indicated sampling was sufficient for data analysis. A total of eight tribes, 16 genera, 59 species and 1590 individuals of Cassidinae beetles were collected. Most belonged to the tribe Hispini (1121 individuals; 70.5%), followed by the tribe Cassidini (161 individuals; 10.13%) and the tribe Oncocephalini (159 individuals; 10.0%). The remainder (149 individuals) belonged to five tribes (Gonophorini, Basiprionotini, Callispini, Notosacanthini and Aspidimorphini). The tribes Notosacanthini, Aspidimorphini and Oncocephalini were newly recorded for Jiangxi Province. There were 14 families, 27 genera and 39 species of host plants of Cassidinae beetles in Longnan County. Cassidinae larvae mainly feed on the plant families Poaceae, Rosaceae, Lamiaceae and Rubiaceae. Most host-plant associations are new reords for the beetle species. This research, together with our planned future work in China, may help to explain the geographical distribution, diversity patterns and host plant associations of these beetles.

[Advances in mechanisms of nutrient exchange between mycorrhizal fungi and host plants]

Mycorrhizae, formed through the colonization of soil mycorrhizal fungi into the roots of host plants, are common symbiosis in the terrestrial ecosystems. The establishment of mycorrhizae is mainly based on the bidirectional nutrient exchanges between the symbiotic partners. Mycorrhizal fungi can absorb mineral nutrients, such as nitrogen and phosphorus, from soil and transport them to the host plants for their growth. As an exchange, host plants supply mycorrhizal fungi with the carbohydrates in the form of lipids or sugars, which are essential for fungal growth. In recent years, the mechanism of nutrient exchange between the mycorrhizal fungi and host plants has been a hot research topic. Important progresses have been achieved in mechanisms of host plants nutrient uptake and transport mediated by the mycorrhizal fungi. In this review, recent advances in nutrient exchange between arbuscular mycorrhizal fungi, ectomycorrhizal fungi and host plants were summarized, especially in the absorption and bidirectional transfer mechanisms of important nutrients, such as carbon, nitrogen and phosphorus. The potential regulatory effects of nutrient exchange in the mycorrhizal development were also reviewed. In addition, key problems and prospects of related researches were analyzed. This paper would be meaningful for the establishment of mycorrhizal model and the optimization of mycorrhizal effects.

Cleonis pigra (Scopoli, 1763) (Coleoptera: Curculionidae: Lixinae): Morphological Re-Description of the Immature Stages, Keys, Tribal Comparisons and Biology

Mature larvae and pupae of Cleonis pigra (Scopoli, 1763) (Curculionidae: Lixinae: Cleonini) are morphologically described in detail for the first time and compared with known larvae and pupae of other Cleonini species. The results of measurements and characteristics most typical for larvae and pupae of Cleonini are newly extracted and critically discussed, along with some records given previously. Keys for the determination of selected Cleonini species based on their larval and pupal characteristics are attached. Dyar’s law was used for the estimation of a number of larval instars of C. pigra. Descriptions of habitats, adult behavior, host plants, life cycle, and biotic interactions are reported here. Adults and larvae feed on plants from the Asteraceae family only (genera Carduus, Cirsium, Centaurea, and Onopordum). Oviposition occurs on the base of the plant stem or the root neck. In the process of larval development, a fusiform gall forms. C. pigra and Cyphocleonus achates can coexist in the same locality. In open habitats, the weevils become the prey of carnivorous animals.

EAG Responses of Adult Lobesia botrana Males and Females Collected from Vitis vinifera and Daphne Gnidium to Larval Host-Plant Volatiles and Sex Pheromone

We analysed electroantennogram (EAG) responses of male and female adults of the European grapevine moth Lobesia botrana (Denis et Schiffermüller) (Lepidoptera: Tortricidae) collected as larvae from grapevine (Vitis vinifera L.) and flax-leaved daphne (Daphne gnidium L.). The host-plant odorants tested were either V. vinifera-specific [1-octen-3-ol, (E)-β-farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene], D. gnidium-specific (2-ethyl-hexan-1-ol, benzothiazole, linalool-oxide, ethyl benzanoate), or were shared by both host-plants (linalool, methyl salicylate). Sex pheromone compounds were also tested. The male response to the major pheromone component (E7,Z9-12:Ac) was higher than to any other stimuli, whereas the response to the minor pheromone components (E7,Z9-12:OH and Z9-12:Ac) was not different from the response to the plant odorants. The female response to pheromone was lower or not different from that to plant odorants. Methyl salicylate elicited a higher response in females and (E)-β-farnesene elicited a higher response than several other plant odorants in both sexes. Non-significant interactions between host-plant odorant and sex indicated an absence of sex specialization for host-plant volatile detection. The lack of a significant interaction between plant volatiles and larval host-plants suggested that there was no specialization for plant-volatile detection between V. vinifera and D. gnidium individuals.

Expression Patterns, Molecular Characterization, and Response to Host Stress of CYP Genes from Phenacoccus solenopsis (Hemiptera: Pseudococcidae)

The quarantine insect pest Phenacoccus solenopsis (Hemiptera: Pseudococcidae) has a broad host range and is distributed worldwide. Each year, P. solenopsis causes significant crop losses. The detoxification of various xenobiotic compounds involves the cytochrome P450 monooxygenase (CYP) superfamily of enzymes. However, the functions of CYPs in P. solenopsis are poorly understood. In the present study, P. solenopsis was reared from the egg to the adult stage on three host plants: Tomato, cotton, and hibiscus. Thirty-seven P. solenopsis CYP genes were identified and their phylogenetic relationships were analyzed. Eleven CYP genes (PsCYP4NT1, PsCYP4G219, PsCYP6PZ1, PsCYP6PZ5, PsCYP301B1, PsCYP302A1, PsCYP305A22, PsCYP315A1, PsCYP353F1, PsCYP3634A1, and PsCYP3635A2) were selected for quantitative real-time PCR analysis. The results demonstrated marked differences in CYP expression levels in P. solenopsis grown on different host plants. The results will aid the molecular characterization of CYPs and will increase our understanding of CYP expression patterns in P. solenopsis during development and growth on different hosts.

The Effects of Locality and Host Plant on the Body Size of Aeolothrips intermedius (Thysanoptera: Aeolothripidae) in the Southwest of Poland

Aeolothrips intermedius is a thrips predator often found in phytocoenoses worldwide. Both the adults and larvae of this species prey on small invertebrates, including phytophagous species from Thysanoptera group. The aim of this study was to determine the morphological variability of the A. intermedius relative to the locality and, indirectly, to the species of host plant. Insects were collected from five localities in southwest Poland and five different host plants. For each of the sexes, six morphometric features were assessed: body length, length of antennae, wing length, head length, head width and length of pronotum. Additionally, the body mass for each individual was estimated. The findings revealed that in females, both the locality and host plant had a significant impact on almost all of these features. In males, the morphometric features under study correlated strongly with locality and only moderately with the host plant. Certain differences were observed between males and females, mainly in terms of antennae length. The results show that A. intermedius exhibits significant variability in this respect, which is indicative of the species’ phenotypic plasticity. The body length was the trait with the most distinct response to the locality and host plant.

Uncovering the Host Range for Maize Pathogen Magnaporthiopsis maydis

The fungus Magnaporthiopsis maydis is a soil-borne, seed-borne vascular wilt pathogen that causes severe damage to sensitive Zea mays L. (maize) hybrids throughout Egypt, Israel, India, Spain, and other countries. It can undergo virulence variations and survive as spores, sclerotia, or mycelia on plant residues. Maize, Lupinus termis L. (lupine) and Gossypium hirsutum L. (cotton) are the only known hosts of M. maydis. Identification of new plant hosts that can assist in the survival of the pathogen is an essential step in restricting disease outbreak and spread. Here, by field survey and growth chamber pathogenicity test, accompanied by real-time PCR analysis, the presence of the fungal DNA inside the roots of cotton (Pima cv.) plants was confirmed in infested soil. Moreover, we identified M. maydis in Setaria viridis (green foxtail) and Citrullus lanatus (watermelon, Malali cv.). Infected watermelon sprouts had delayed emergence and development, were shorter, and had reduced root and shoot biomass. M. maydis infection also affected root biomass and phenological development of cotton plants but caused only mild symptoms in green foxtail. No M. maydis DNA was detected in Hordeum vulgare (barley, Noga cv.) and the plants showed no disease symptoms except for reduced shoot weight. These findings are an important step towards uncovering the host range and endophytic behavior of M. maydis, encouraging expanding this evaluation to other plant species.

Male pheromone composition depends on larval but not adult diet in Heliconius melpomene

1. Condition-dependent traits can act as honest signals of mate quality, with fitter individuals being able to display preferred phenotypes. Nutrition is known to be an important determinant of individual condition, with diet known to affect many secondary sexual traits. 2. In Heliconius butterflies, male chemical signalling plays an important role in female mate choice. Potential male sex pheromone components have been identified previously, although it is unclear what information they convey to the female. 3. In the present study, the effect of diet on androconial and genital compound production is tested in male Heliconius melpomene rosina. To manipulate larval diet, larvae are reared on three different Passiflora host plants: Passiflora menispermifolia, the preferred host plant, Passiflora vitifolia and Passiflora platyloba. To manipulate adult diet, adult butterflies are reared with and without access to pollen, a key component of their diet. 4. No evidence is found to suggest that adult pollen consumption affects compound production in the first 10 days after eclosion. There is also a strong overlap in the chemical profiles of individuals reared on different larval host plants. The most abundant compounds produced by the butterflies do not differ between host plant groups. However, some compounds found in small amounts differ both qualitatively and quantitatively. Some of these compounds are predicted to be of plant origin and the others synthesised by the butterfly. Further electrophysiological and behavioural experiments will be needed to determine the biological significance of these differences.

A biotrophic fungal infection of the great burnet Sanguisorba officinalis indirectly affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius

Interactions between ecological communities of herbivores and microbes are commonly mediated by a shared plant. A tripartite interaction between a pathogenic fungus-host plant-herbivorous insect is an example of such mutual influences. In such a system a fungal pathogen commonly has a negative influence on the morphology and biochemistry of the host plant, with consequences for insect herbivore performance. Here we studied whether the biotrophic fungus Podosphaera ferruginea, attacking the great burnet Sanguisorba officinalis, affects caterpillar performance of the endangered scarce large blue butterfly Phengaris teleius. Our results showed that the pathogenic fungus affected the number and size of inflorescences produced by food-plants and, more importantly, had indirect, plant-mediated effects on the abundance, body mass and immune response of caterpillars. Specifically, we found the relationship between caterpillar abundance and variability in inflorescence size on a plant to be positive among healthy food-plants, and negative among infected food-plants. Caterpillars that fed on healthy food-plants were smaller than those that fed on infected food-plants in one studied season, while there was no such difference in the other season. We observed the relationship between caterpillar immune response and the proportion of infected great burnets within a habitat patch to be positive when caterpillars fed on healthy food-plants, and negative when caterpillars fed on infected food-plants. Our results suggest that this biotrophic fungal infection of the great burnet may impose a significant indirect influence on P. teleius caterpillar performance with potential consequences for the population dynamics and structure of this endangered butterfly.

Feeding Specialization of Flies (Diptera: Richardiidae) in Aroid Infructescences (Araceae) of the Neotropics

Evolution and radiation between insects and flowering plants are both opportunistic and obligatory when the former feeds on the reproductive structures of the latter, whereas direct and indirect effects can influence the fitness of individuals, populations, and plant communities. The Araceae family constitutes an important element of the tropical rainforest of the Neotropics, and its morphology and floral biology provide a remarkable system for studying trophic interactions with insects, including the Richardiidae flies (Diptera). We studied the trophic interactions of the aroid-fly system, assessing infestation rates under natural conditions over an annual cycle. In the Neotropical region, we discovered for the first time that seven aroid species became infested by four richardiid species: Beebeomyia tuxtlaensis Hernández-Ortiz and Aguirre with Dieffenbachia oerstedii Schott and D. wendlandii Schott; B. palposa (Cresson) with Xanthosoma robustum Schott; Beebeomyia sp.3. in association with Philodendron radiatum Schott, P. tripartitum (Jacq.) Schott, and P. sagittifolium Liebm.; while Sepsisoma sp. only infested Rhodospatha wendlandii Schott. Infestation rates differed significantly among hosts, but comparisons with morphological traits did not provide evidence of a causal factor of the infestation. In contrast, larval density and time of development both exhibited significant differences between hosts. The findings suggest the high specialization of the flies, and that intrinsic factors of the plants, such as the presence of secondary metabolites and their maturation periods, may influence their infestation rates.

Electrophysiological and Behavioral Responses of the Kudzu Bug, Megacopta cribraria (Hemiptera: Plataspidae), to Volatile Compounds from Kudzu and Soybean Plants

The kudzu bug, Megacopta cribraria, is a key pest of soybean in the United States. Electrophysiological and behavioral responses of adult M. cribraria to kudzu and soybean volatile compounds were examined to identify semiochemicals used for host location. Headspace volatiles collected from undamaged potted plants were analyzed by gas chromatography with electroantennographic detection (GC-EAD). Subsequently, six GC-EAD-active compounds were identified by gas chromatography-mass spectrometry (GC-MS). These six compounds, along with some previously reported insect attractants, were selected for electroantennogram (EAG) assays. The four chemicals that elicited the strongest EAG responses, 1-octen-3-ol, nonanal, benzaldehyde, and ocimene, were selected for evaluation in olfactometer bioassays. Both benzaldehyde and 1-octen-3-ol exhibited dose-dependent responses at higher concentration. Our results provide insight into host location compounds used by adult M. cribraria. These results may be evaluated in future field tests and ultimately useful to develop a semiochemical-based monitoring technique and integrated pest management program for M. cribraria.

Plant Hormones in Phytoplasma Infected Plants

Phytoplasmas are bacterial plant pathogens that need a plant host and an insect vector for their spread and survival. In plants, the physiological responses that phytoplasmas trigger result in symptom development through effects on hormonal, nutritional, and stress signaling pathways, and the interactions between these. In this review, recent advances on the involvement of plant hormones together with their known and deduced roles in plants infected with phytoplasmas are discussed. Several studies have directly, or in many cases indirectly, addressed plant hormone systems in phytoplasma-infected plants. These have provided accumulating evidence that phytoplasmas extensively affect plant hormone pathways. Phytoplasmas thus, with disturbing complex plant hormone networks, suppress plant immunity and modify plant structure, while optimizing their nutrient acquisition and facilitating their colonization of the plants, and their dissemination among plants by their insect vectors.

Distinct replication and gene expression strategies of the Rice Stripe virus in vector insects and host plants

Persistent propagative plant viruses are usually transmitted between a vector insect and a host plant. To adapt to the two different organisms, viruses may show distinct genomic replication or gene expression patterns. To verify this hypothesis, we applied an aboslute real-time quantitative PCR method to measure and compare the replication levels of four genomic RNA segments and the expression levels of seven genes of rice stripe virus (RSV) according to the infection time in the small brown planthopper and rice plant, respectively. In the vector insect, RNA3 began replicating later than the other segments, and RNA2 remained nearly constant during the infection process. RNA1 was the dominant segment, and a difference of over 300-fold appeared among the four segments. In rice plants, the size of the four segments increased with infection time, but decreased to a low level in the late infection period. The ratios of the four segments varied by no more than 15-fold. In planthoppers, three expression patterns were observed for the seven viral genes during viral infection, while in rice plants, the expression patterns of the seven viral genes were similar. These results reflect distinct genomic replication and gene expression patterns in a persistent propagative plant virus in adapting to vector insects and host plants.

Molecular characterization and expression patterns of Phenacoccus solenopsis (Hemiptera: Pseudococcidae) heat shock protein genes and their response to host stress

As a polyphagous insect, little is known at the molecular level about the effects of different host plants on physiological changes in Phenacoccus solenopsis. In this study, four heat shock protein (Hsp) genes (PsHsp60, PsHsp70, PsHsp90, and PsHsp20.7) were identified from the transcriptome of P. solenopsis. Analysis of Hsp expression levels revealed significant differences in Hsp gene expression levels in P. solenopsis fed on different host plants. In host conversion tests, the expression levels of PsHsp90 and PsHsp60 were upregulated after transfer of second instar nymphs from tomato to cotton. The expression levels of PsHsp70 and PsHsp20.7 were, respectively, significantly upregulated at 9 and 48 hr after transfer from tomato to Hibiscus. The results of this study aid molecular characterization and understanding of the expression patterns of Hsp genes during different developmental stages and host transfer of P. solenopsis.

Size and shape analysis of Trioza erytreae Del Guercio (Hemiptera: Triozidae), vector of citrus huanglongbing disease

BACKGROUND

The African citrus triozid (ACT) Trioza erytreae Del Guercio (Hemiptera: Triozidae) is one of the most devastating pests of citrus with a well-known role as a vector of the phloem-limited bacteria (Candidatus Liberibacter africanus) associated with huanglongbing (citrus greening disease), currently considered the world's most serious disease of citrus. Although the pest can successfully develop and reproduce on non-citrus host plants, there is no documented information on the geometric morphometry of ACT. We determine the effect of host plants on ACT morphometry under controlled laboratory conditions using traditional and geometric analysis.

RESULTS

ACT reared on C. limon and Citroncirus spp. was significantly larger than when reared on the other host plant species. ACT reared on C. anisata and C. tangelo was consistently smaller than that reared on M. koenigii and C. sinensis. Based on warped outline drawings, ACT reared on Citroncirus spp. and Murraya koenigii had narrower wings than when reared on C. anisata, C. limon, and C. sinensis with slightly broader wing patterns.

CONCLUSION

This study clearly demonstrates that host plant species affect morphometric variation in ACT, which might have a direct impact on fitness parameters of the pest as well as its potential for dispersion. Wing shape and size appear to be useful in separating populations of ACT into different groups. © 2018 Society of Chemical Industry.

The morphology of the preimaginal stages of Rhinusaneta (Germar, 1821) and notes on its biology (Coleoptera, Curculionidae, Mecinini)

A detailed description of the mature larva and pupa of Rhinusaneta (Germar, 1821) and new diagnostic features of this species are presented. The development cycle of R.neta in the standard conditions lasts almost 60 days: an 11-day egg period, a 29-day larval period, and an 18-day pupal period, on average. The larvae are parasitised by hymenopterans of the superfamily Chalcidoidea. Similarities and differences with Rhinusabipustulata and other species of this genus are presented.

The morphology of the preimaginal stages of Cleopomiarusmicros (Germar, 1821) (Curculionidae, Coleoptera) and notes on its biology

As yet little is known of the bionomics of weevils of the genus Cleopomiarus Pierce, 1919; current knowledge is limited to data on the morphology and biology of the preimaginal stages of certain species. This paper includes original information on the life cycle of Cleopomiarusmicros (Germar, 1821). It presents the morphology of the egg, last larva (L₃) and pupa. Data on the host plant (Jasionemontana L.) and breeding plant (Campanulapatula L.) and on the oviposition and phenology of the species are updated. The anatomy of the third-stage larva of C.micros shares certain traits with other species of the tribe Mecinini Gistel, 1848. Comparison of the morphology of preimaginal stages of C.micros with those previously described for other species of the genera Cleopomiarus and Miarus Schönherr, 1826 - previously considered the same genus - reveals species differences in larval body length, colour of the body and epicranium, and chaetotaxy of head and body.