Insect Host Research Articles

Preference and performance in an herbivorous coccinellid beetle: a comparative study of host plant defensive traits, insect preference, and survival

Preference and performance in an herbivorous coccinellid beetle: a comparative study of host plant defensive traits, insect preference, and survival

Prospects for Biological Control of Macadamia Felted Coccid in Hawaii with Metaphycus macadamiae Polaszek & Noyes, a New Encyrtid Wasp Native to New South Wales, Australia.

Macadamia felted coccid (MFC), Acanthococcus ironsidei (Williams) (Hemiptera: Eriococcidae), was first discovered in 2005 on the Island of Hawaii. Host plants are restricted to Macadamia species, with Macadamia integrifolia Maiden & Betche (Proteaceae) being grown in Hawaii for nut production. Approximately 6839 hectares macadamia nuts are harvested in Hawaii with an estimated farm value of USD 48.8 million (2019-2020 records). Exploration in Australia started in November 2013 for the evaluation of potential parasitoids being host specific for introduction into Hawaii. A dominant solitary endoparasitoid of MFC from New South Wales was discovered and described as Metaphycus macadamiae Polaszek & Noyes sp. n (Hymenoptera: Encyrtidae: Encyrtinae). Biology and host specificity testing were conducted at the Hawaii Department of Agriculture, Insect Containment Facility, on nine hemipteran and three lepidopteran eggs. Results indicated that M. macadamiae is host specific to MFC. There has been no evidence of parasitism or host feeding on any of the non-target insect hosts that were tested. Parasitoid emergence from the control (MFC) averaged 30.2% compared to 0% on non-target hosts. A low rate of parasitoid emergence in the laboratory (average 30.2%) and an increased rate of MFC nymphal mortality was due to adult feeding. Field parasitism reached up to 32.7% emergence in Alstonville, New South Wales, Australia. We report on the parasitoid performance in native Australia, rearing biology, host specificity testing, and the extant natural enemies associated with MFC in Hawaii. A petition to release this parasitoid for the biocontrol of MFC in Hawaii is pending. Once permitted for release, the colony will be shared with South African Mac Nut Association for their biocontrol program of this invasive pest. They will conduct their own testing before approval for release.

Arsenophonus symbiosis with louse flies: multiple origins, coevolutionary dynamics, and metabolic significance.

Arsenophonus is a widespread insect symbiont with life strategies that vary from parasitism to obligate mutualism. In insects living exclusively on vertebrate blood, mutualistic Arsenophonus strains are presumed to provide B vitamins missing in the insect host diet. Hippoboscidae, obligate blood feeders related to tsetse flies, have been previously suggested to have acquired Arsenophonus symbionts in several independent events. Based on comparative genomic analyses of 11 Hippoboscidae-associated strains, 9 of them newly assembled, we reveal a wide range of their genomic characteristics and phylogenetic affiliations. Phylogenetic patterns and genomic traits split the strains into two different types. Seven strains display characteristics of obligate mutualists with significantly reduced genomes and long phylogenetic branches. The remaining four strains cluster on short branches, and their genomes resemble those of free-living bacteria or facultative symbionts. Both phylogenetic positions and genomic traits indicate that evolutionary history of the Hippoboscidae-Arsenophonus associations is a mixture of short-term coevolutions with at least four independent origins. The comparative approach to a reconstruction of B vitamin pathways across the available Arsenophonus genomes has produced two kinds of patterns. On one hand, it indicates the different importance of individual B vitamins in the host-symbiont interaction. While some (riboflavin, pantothenate, and folate) seem to be synthesized by all Hippoboscidae-associated obligate symbionts, pathways for others (thiamine, nicotinamide, and cobalamin) are mostly missing. On the other hand, the broad comparison has produced patterns that can serve as bases for further assessments of the pathways' completeness and functionality. IMPORTANCE Insects that live exclusively on vertebrate blood utilize symbiotic bacteria as a source of essential compounds, e.g., B vitamins. In louse flies, the most frequent symbiont originated in genus Arsenophonus, known from a wide range of insects. Here, we analyze genomic traits, phylogenetic origins, and metabolic capacities of 11 Arsenophonus strains associated with louse flies. We show that in louse flies, Arsenophonus established symbiosis in at least four independent events, reaching different stages of symbiogenesis. This allowed for comparative genomic analysis, including convergence of metabolic capacities. The significance of the results is twofold. First, based on a comparison of independently originated Arsenophonus symbioses, it determines the importance of individual B vitamins for the insect host. This expands our theoretical insight into insect-bacteria symbiosis. The second outcome is of methodological significance. We show that the comparative approach reveals artifacts that would be difficult to identify based on a single-genome analysis.

Host-associated transmission favors transition of a commensal towards antagonism.

The impacts of host-associated microbes for their hosts varies along a continuum of antagonistic, neutral, and beneficial interactions. Transmission mode is predicted to contribute to transitions along the continuum by altering opportunities for the alignment of host and microbe fitness interests. Under vertical transmission, microbial evolution is tightly coupled to the host environment, which may facilitate fitness alignment. In contrast, environmentally transmitted microbes spend time in the external environment, outside of hosts, partially decoupling their evolution from the host. This decoupling may misalign host and microbe fitness interests, potentially favoring antagonistic microbial traits. Here, we tested whether transmission environment alters microbial evolution by manipulating the interaction between a commensal Serratia marcescens bacteria and their insect host Anasa tristis, which are the primary vector of these bacteria into plants, where they cause disease. We experimentally evolved S. marcescens through several selection environments. The bacteria were passaged between A. tristis hosts, between A. tristis hosts and soil, through soil, or through standard culture media. We observed rapid evolution of virulence toward hosts across treatments when bacterial evolution occurred within the host environment, indicating that direct host-to-host transmission can increase opportunities for microbes to adapt to hosts and evolve antagonistic traits.

Comparative transcriptome analysis to unveil genes affecting the host cuticle destruction in Metarhizium rileyi.

Insect pathogenic fungi, also known as entomopathogenic fungi, are one of the largest insect pathogenic microorganism communities, represented by Beauveria spp. and Metarhizium spp. Entomopathogenic fungi have been proved to be a great substitute for chemical pesticide in agriculture. In fact, a lot of functional genes were also already characterized in entomopathogenic fungi, but more depth of exploration is still needed to reveal their complicated pathogenic mechanism to insects. Metarhizium rileyi (Nomuraea rileyi) is a great potential biocontrol fungus that can parasitize more than 40 distinct species (mainly Lepidoptera: Noctuidae) to cause large-scale infectious diseases within insect population. In this study, a comparative analysis of transcriptome profile was performed with topical inoculation and hemolymph injection to character the infectious pattern of M. rileyi. Appressorium and multiple hydrolases are indispensable constituents to break the insect host primary cuticle defense in entomopathogenic fungi. Within our transcriptome data, numerous transcripts related to destruction of insect cuticle rather growth regulations were obtained. Most importantly, some unreported ribosomal protein genes and novel unannotated protein (hypothetical protein) genes were proved to participate in the course of pathogenic regulation. Our current data provide a higher efficiency gene library for virulence factors screen in M. rileyi, and this library may be also useful for furnishing valuable information on entomopathogenic fungal pathogenic mechanisms to host.

Composition and diversity of gut microbiota across developmental stages of Spodoptera frugiperda and its effect on the reproduction.

Spodoptera frugiperda is a serious world-wide agricultural pest. Gut microorganisms play crucial roles in growth, development, immunity and behavior of host insects. Here, we reported the composition of gut microbiota in a laboratory-reared strain of S. frugiperda using 16S rDNA sequencing and the effects of gut microbiota on the reproduction. Proteobacteria and Firmicutes were the predominant bacteria and the taxonomic composition varied during the life cycle. Alpha diversity indices indicated that the eggs had higher bacterial diversity than larvae, pupae and adults. Furthermore, eggs harbored a higher abundance of Ralstonia, Sediminibacterium and microbes of unclassified taxonomy. The dynamics changes in bacterial communities resulted in differences in the metabolic functions of the gut microbiota during development. Interestingly, the laid eggs in antibiotic treatment groups did not hatch much due to the gut dysbacteriosis, the results showed gut microbiota had a significant impact on the male reproduction. Our findings provide new perspectives to understand the intricate associations between microbiota and host, and have value for the development of S. frugiperda management strategies focusing on the pest gut microbiota.

Impact of gut microbiota composition on black cutworm, Agrotis ipsilon (hufnagel) metabolic indices and pesticide degradation

Endosymbionts are known to have significant effects on their insect hosts, including nutrition, reproduction, and immunity. Insects gut microbiota is a critical component that affects their physiological and behavioral characteristics. The black cutworm (BCW), Agrotis ipsilon, is an economically important lepidopteran pest that has a diverse gut microbiome composed of nine species belonging to three phyla: Proteobacteria, Actinobacteria, and Firmicutes. This study was conducted to investigate the diversity of gut bacteria isolated from BCW larvae and moths and their effects on metabolism and pesticide degradation. The bacterial isolates were identified using the 16 S rRNA gene. The study showed that the gut microbiome composition significantly affected the metabolism of BCW larvae. Based on the screening results of synthesis of digestive enzymes and pesticide degradation, Brachybacterium conglomeratum and Glutamicibacter sp were selected to perform the remaining experiments as single isolates and consortium. The consortium-fed larvae showed high metabolic indices compared to antibiotic-fed larvae and the control. The gut bacteria were also shown to degrade three pesticide groups. Concerns regarding the health risk of chlorpyrifos have been raised due to its extensive use in agriculture. The isolated B. conglomeratum was more effective in chlorpyrifos degradation than the consortium. Furthermore, the study also examined the presence of sex related endosymbionts (Wolbachia, Spiroplasma, and Rickettsia) in the reproductive tissues of adults. The outcomes demonstrated that none of the examined endosymbionts existed. In conclusion, the study highlights the importance of the gut microbiome in insect physiology and behavior and its potential applications in biotechnology. It provides insights into developing eco-friendly pest control and bioremediation strategies using gut bacteria.

Transcriptome and gut microbiota analyses reveal a possible mechanism underlying rifampin-mediated interruption of the larval development of chironomid Propsilocerus akamusi (Diptera: Chironomidae)

Chironomids, the most abundant insect group found in freshwater habitats, are known to be pollution tolerate and serve as important bioindicators of contaminant stress. Gut microbiota has recently been shown to potentially provide a number of beneficial services to insect hosts. However, the antibiotic-mediated interruption of chironomid gut microbial community and its subsequent influence on host body are still unclear. In the present study, the effects of rifampin on chironomid larvae were investigated at both transcriptome and microbiome level to assess the relationship between gut bacteria and associated genes. Our data indicated that the rifampin-induced imbalance of gut ecosystem could inhibit the development of chironomid larvae via decreasing the body weight, body length and larval eclosion rate during 96-h treatment. Both the community structure and taxonomic composition were significantly altered due to the invasion of rifampin in digestive tracts. The relative abundance of phylum Deferribacterota and Bacteroidota were dramatically increased with rifampin exposure. A set of genes involved in amino acid synthesis as well as xenobiotic metabolism pathways were greatly changed and proved to have tight correlation with certain genus. Bacterial genus Tyzzerella was positively correlated with detoxifying PaCYP6GF1 and PaCYP9HL1 genes. This study provides a reference for understanding the environmental risks of antibiotic and aims to accelerate new biological insights into the effects of antibiotic on the fitness of chironomids and into the microbe mediated-regulatory mechanism of aquatic insects.

Oviposition fluids from adult wasps mediate interspecific competition between parasitoid larvae

Abstract Parasitoid wasp larvae engage in intense interspecific competition when sharing a host insect, with lethal consequences for the losers. Larval parasitoid competition is generally thought to be resolved by physical traits, such as enlarged mandibles. Although solitary parasitoid larvae are typically superior competitors against gregarious larvae, such physical traits are unlikely to be effective against large numbers of competitors. Larval competition may instead be mediated by maternal factors that increase the survival of offspring facing interspecific competition, thus increasing parental fitness. When laying eggs inside a host, many female parasitoids also inject oviposition fluids that are known to suppress host immune responses, permitting successful offspring development. We explored whether the oviposition fluids of two wasp species in the genus Cotesia (Cotesia rubecula, a strong competitor that almost always wins interspecific competition against a weaker competitor, Cotesia glomerata) might also represent maternal factors that improve the interspecific competitive ability of their offspring. We demonstrate that injections of both venom and calyx fluid from C. rubecula can inhibit egg hatching and larval development of C. glomerata. Venom from C. rubecula decreased C. glomerata egg development by 2.7 times, and calyx fluid injections caused deformities in 23% of developing C. glomerata. In contrast, reciprocal injections of the oviposition fluids from C. glomerata did not inhibit the development of C. rubecula. Our results show that maternal factors can improve the interspecific competitive ability of parasitoid larvae, challenging the previous assumptions that larval competition was resolved primarily through physical combat or larval secretions.

What Is More Important to Host-Seeking Entomopathogenic Nematodes, Innate or Learned Preference?

Entomopathogenic nematodes (EPNs), small soil-dwelling non-segmented roundworms, are obligate parasites of insects and commonly used in agriculture for biological control of insect pests. For successful reproduction, EPNs must identify, move towards, and successfully infect a suitable insect host in a chemically complex soil environment. EPNs can have innate host insect preferences and can be attracted to semiochemicals associated with that host. They can also develop strong learned preferences for chemical signals associated with the presence of a host, such as herbivory-induced volatiles. We hypothesized that simultaneous manipulation of innate and learned preferences could result in increased biological control services of EPNs in agriculture. Separate cohorts of the EPN Steinernema diaprepesi were raised on two insect hosts, Galleria mellonella and Tenebrio molitor, for multiple generations until the nematodes in a dual-choice olfactometer exhibited preference for the host they were reared on. Subsequently, the two strains of nematodes were imprinted on three plant-produced terpenoids of agricultural significance: pregeijerene, β-caryophyllene, and α-pinene. After exposure to one of the plant compounds, the behavior of the EPNs was assayed in an olfactometer where the two host insects were presented with and without the plant compounds. We found that plant volatile exposure increased the infection rate of the nematodes, and some host–compound combinations proved to be attractive, but other combinations appeared to become repellent. These results indicate that learned preference is neither subordinate nor superior to innate preference, and that infection efficiency can vary with compound exposure and insect host.

Species diversity of environmentally-transmitted bacteria colonizing Riptortus pedestris (Hemiptera: Alydidae) and symbiotic effects of the most dominant bacteria

Riptortus pedestris (Hemiptera: Alydidae) establish endosymbiosis with specific bacteria from extremely diverse microbiota in soil. To better understand ecology and evolution of the symbiosis, it is important to characterize bacterial species diversity colonizing R. pedestris and evaluate their symbiotic effects. Nonetheless, previous research was limited to a few bacteria strains such as Caballeronia insecticola. In this study, second-instar nymphs were provided with field soils and reared to adult. Then, bacteria colonizing the midgut M4 region of R. pedestris were analyzed for bacterial species identification based on the 16S rRNA gene. First, a total of 15 bacterial species were detected belonging to Burkholderiaceae. Most of R. pedestris were found to harbor single bacterial species, whereas several insects harbored at most two bacterial species simultaneously. Among the total insects harboring single bacterial species, 91.2% harbored genus Caballeronia. The most dominant species was C. jiangsuensis, not previously documented for symbiotic associations with R. pedestris. Second, in laboratory conditions, C. jiangsuensis significantly enhanced the development, body size, and reproductive potentials of R. pedestris, compared to individuals with no symbiotic bacteria. These results add novel information to better understand symbiotic bacteria community establishing in R. pedestris and symbiotic effects on the host insects.

The man, the plant, and the insect: shooting host specificity determinants in Serratia marcescens pangenome.

Serratia marcescens is most commonly known as an opportunistic pathogen causing nosocomial infections. It, however, was shown to infect a wide range of hosts apart from vertebrates such as insects or plants as well, being either pathogenic or growth-promoting for the latter. Despite being extensively studied in terms of virulence mechanisms during human infections, there has been little evidence of which factors determine S. marcescens host specificity. On that account, we analyzed S. marcescens pangenome to reveal possible specificity factors. We selected 73 high-quality genome assemblies of complete level and reconstructed the respective pangenome and reference phylogeny based on core genes alignment. To find an optimal pipeline, we tested current pangenomic tools and obtained several phylogenetic inferences. The pangenome was rich in its accessory component and was considered open according to the Heaps' law. We then applied the pangenome-wide associating method (pan-GWAS) and predicted positively associated gene clusters attributed to three host groups, namely, humans, insects, and plants. According to the results, significant factors relating to human infections included transcriptional regulators, lipoproteins, ABC transporters, and membrane proteins. Host preference toward insects, in its turn, was associated with diverse enzymes, such as hydrolases, isochorismatase, and N-acetyltransferase with the latter possibly exerting a neurotoxic effect. Finally, plant infection may be conducted through type VI secretion systems and modulation of plant cell wall synthesis. Interestingly, factors associated with plants also included putative growth-promoting proteins like enzymes performing xenobiotic degradation and releasing ammonium irons. We also identified overrepresented functional annotations within the sets of specificity factors and found that their functional characteristics fell into separate clusters, thus, implying that host adaptation is represented by diverse functional pathways. Finally, we found that mobile genetic elements bore specificity determinants. In particular, prophages were mainly associated with factors related to humans, while genetic islands-with insects and plants, respectively. In summary, functional enrichments coupled with pangenomic inferences allowed us to hypothesize that the respective host preference is carried out through distinct molecular mechanisms of virulence. To the best of our knowledge, the presented research is the first to identify specific genomic features of S. marcescens assemblies isolated from different hosts at the pangenomic level.

Deconstructing taxa x taxa x environment interactions in the microbiota: A theoretical examination

A major objective of microbial ecology is to identify how the composition of microbial taxa shapes host phenotypes. However, most studies focus on pairwise interactions and ignore the potentially significant effects of higher-order microbial interactions.Here, we quantify the effects of higher-order interactions among taxa on host infection risk. We apply our approach to an in silico dataset that is built to resemble a population of insect hosts with gut-associated microbial communities at risk of infection from an intestinal parasite across a breadth of nutrient environmental contexts.We find that the effect of higher-order interactions is considerable and can change appreciably across environmental contexts. Furthermore, we show that higher-order interactions can stabilize community structure thereby reducing host susceptibility to parasite invasion.Our approach illustrates how incorporating the effects of higher-order interactions among gut microbiota across environments can be essential for understanding their effects on host phenotypes.

Investigation on Flavescence Dorée in North-Western Italy Identifies Map-M54 (16SrV-D/Map-FD2) as the Only Phytoplasma Genotype in Vitis vinifera L. and Reveals the Presence of New Putative Reservoir Plants.

Flavescence dorée (FD) is the most important phytoplasma-associated disease of the grapevine yellows complex in Europe. Recent studies highlighted a great genetic diversity within FD phytoplasma (FDp) strains and demonstrated that their diffusion is not related exclusively to the pathosystem including Vitis vinifera L. and Scaphoideus titanus but involves additional vectors and reservoir plants. This study aimed to investigate FD epidemiology in north-western Italy, with a particular focus on FDp hosts. During field surveys, leaf samples were collected from symptomatic grapevines and other symptomless plant species, and insects were collected within and around vineyards. Phytoplasmas belonging to the ribosomal group 16SrV were detected and typed using nested-PCR-based amplification and nucleotide sequence analyses of the map gene. All symptomatic grapevines were found to be infected by the FDp genotype M54, prevalent in S. titanus and also identified in other known and newly reported hosts. Interestingly, other FDp strains (M38, M50, M51, M121) and FDp-related strains (M39, M43, M48), never detected in grapevines, were largely identified in several known and newly reported host plants and insects including S. titanus. Such evidence confirmed the complexity of FD ecology, expanding the knowledge on the range of FDp host plants putatively involved in the disease spread.

Symbiotic Bacteria Regulating Insect-Insect/Fungus/Virus Mutualism.

Bacteria associated with insects potentially provide many beneficial services and have been well documented. Mutualism that relates to insects is widespread in ecosystems. However, the interrelation between "symbiotic bacteria" and "mutualism" has rarely been studied. We introduce three systems of mutualism that relate to insects (ants and honeydew-producing Hemiptera, fungus-growing insects and fungi, and plant persistent viruses and vector insects) and review the species of symbiotic bacteria in host insects, as well as their functions in host insects and the mechanisms underlying mutualism regulation. A deeper understanding of the molecular mechanisms and role of symbiotic bacteria, based on metagenomics, transcriptomics, proteomics, metabolomics, and microbiology, will be required for describing the entire interaction network.

Correlation of fruit tree rhizosphere soils with entomopathogenic fungi

AbstractEntomopathogenic fungi are microorganisms that control the density of host insects in nature; they are being studied as environmentally friendly alternatives to chemical insecticides for controlling insect pests. The main habitat of entomopathogenic fungi is soil, and the correlation between the distribution of entomopathogenic fungi and the physicochemical characteristics of soils planted with different trees, including vine (outdoor, greenhouse, and greenhouse shine musket), apple, peach, and pear, were analyzed. The entomopathogenic fungi of the genera Beauveria, Metarhizium, and Purpureocillium investigated in this study were all found in soil samples from vine‐greenhouse, apple, and peach trees. Purpureocillium and Beauveria abundances were positively correlated with soil properties; however, Metarhizium abundances were not correlated with soil properties. The Metarhizium isolates discovered in this study showed pathogenicity to cotton aphids (an agricultural pest) and can be employed as sources for biological studies in the future. This study provides data on the diversity and abundance of entomopathogenic fungi related with soil properties, as well as the molecular, biological, and insecticidal characteristics of Metarhizium isolates.

A 'Candidatus Liberibacter solanacearum' Haplotype B-Specific Family of Candidate Bacterial Effectors.

'Candidatus Liberibacter solanacearum' (Lso) is a phloem-limited pathogen associated with devastating diseases in members of the Solanaceae and Apiaceae and vectored by several psyllid species. Different Lso haplotypes have been identified, and LsoA and LsoB are responsible for diseases in Solanaceae crops. Our efforts are aimed at identifying pathogenicity factors used by this bacterium to thrive in different hosts. Bacterial secreted proteins can play a role in host colonization or the manipulation of the host immune responses; these proteins are called effectors. In this study, we identified six LsoB-specific proteins with a conserved secretion motif as well as a conserved N-terminal domain in the mature protein. These proteins had different expression and secretion patterns but a similar subcellular localization in Nicotiana benthamiana leaves, suggesting that they play different roles regardless of their conserved secretion motif. One of these proteins, CKC_04425, was expressed at high levels in the insect vector and the host plant, indicating that it could play a role in both the plant and insect hosts, whereas the others were mainly expressed in the plant. One protein, CKC_05701, was able to efficiently suppress programmed cell death and reactive oxygen species production, suggesting that it may have a virulence role in LsoB-specific pathogenesis.

Insect Mortality Caused by Baculovirus: a Model of Second-Order Phase Transitions

Baculoviruses, especially prevalent in Lepidoptera, have attracted the most attention as biological insect control agents. Infection with baculoviruses is usually fatal and therefore can affect host population density, especially if virus transmission increases with host density. Lepidoptera larvae show a strong dose-dependent response to pathogens such as baculoviruses, so their response to various pathogen exposures was studied in the present work. Models of virus exposure to insect hosts are usually judged by whether or not they generate cyclical population dynamics of multiple host generations. However, the existing theoretical models based on systems of differential equations are of little use for practical application due to the large number of variables and free parameters. In this regard, the possibility of using a mathematical model for describing the epizootic Malacosoma neustria L. and Lymantria dispar L. under the influence of nuclear polyhedrosis virus is considered. To assess the sensitivity of insects to the effects of baculoviruses, laboratory experiments were carried out on the mortality of caterpillars under various infectious loads. In this paper, we consider the possibility of constructing a model for the lifetime of insects after exposure to baculoviruses as an analogue of a second-order phase transition in physical systems and give estimates of the model parameters for two insect species at different titers of baculoviruses and at different ages of caterpillars. The dependence of the parameters of the proposed model on nuclear polyhedrosis virus strains is shown. The importance of the applied parameters for the organization of forest protection measures is substantiated.

A Taxonomic Study of Some Species of Hyperparasitoids Attacking the Primary Parasitoid Microterys nietneri of the Citricola Scale Insect, Coccus pseudomagnoliarum in Syria

Saleh, A.T. and A.M. Basheer. 2023. A Taxonomic Study of Some Species of Hyperparasitoids Attacking the Primary Parasitoid Microterys nietneri of the Citricola Scale Insect, Coccus pseudomagnoliarum in Syria. Arab Journal of Plant Protection, 41(3): 292-305. https://doi.org/10.22268/AJPP-41.3.292305 The citricola scale insect, Coccus pseudomagnoliarum, (Kuwana) (Hemiptera: Coccomorpha: Coccidae) is an economically important pest that occurs on citrus trees along the Syrian coast. The samples of host insects and infested plant parts were collected from April to June during 2016 and 2017 from two locations (Al-Sanobar, Dabba) in Lattakia Province and brought to the Biological Control Studies and Research Center (BCSRC), Faculty of Agriculture, Damascus University. Based on the information gathered, Microterys nietneri (Motschulsky) (Hymenoptera: Encyrtidae) may play an important role as a biological control agent of citricola scale insect, but high hyperparasitoids levels reduced M. nietneri efficiency as a citricola scale parasitoid. The objective of this study was to describe and identify naturally occurring hyperparasitoids. The following parasitoids were identified and reported for the first time in Syria: Cheiloneurus claviger (Thomson), Pachyneuron muscarum (Linnaeus), and Marietta leopardine (Motschulsky). Microscopic images were provided to illustrate the morphological and morphometric characteristics of these species. Keywords: Hyperparasitoids, Citricola scale, Microterys, Syria

Fungal co-expression network analyses identify pathogen gene modules associated with host insect invasion.

The broad host range fungal insect pathogen, Beauveria bassiana, has been commercialized as an alternative to chemical insecticides for pest control worldwide. B. bassiana represents a unique model system with which to examine host-pathogen interactions, and a wide range of genes and processes have been studied. However, significant aspects of virulence, particularly on the genomic scale, remain poorly studied. Here, we have combined available transcriptomes with three newly generated data sets for a combined total analysis of 76 deep-sequenced samples covering growth, development, stress responses, and infection during the life cycle of B. bassiana. Co-expression network analyses resulted in the identification of gene modules enriched during two critical stages of the infection process, namely (i) cuticle penetration and (ii) in vivo hyphal body (dimorphic transition) growth capable of avoiding innate and humoral immune defenses. These analyses identify unique signatures of metabolism, signaling, secondary metabolite production, host defense suppression, membrane reorganization, effector production, and secretion for each stage, including genetic regulators and epigenetic patterns. These data provide a comprehensive framework for understanding and probing fungal adaptations to its pathogenic life cycle and expand the candidate repertoire for continued dissection of the host-pathogen interaction. IMPORTANCE Insect fungal pathogens have evolved unique strategies for overcoming host structural and immunological defenses that span from the sclerotized cuticle to innate and humoral cellular responses. Two critical stages of the infection process involve (i) cuticle penetration and (ii) immune evasion within the insect hemocoel. A set of 76 global transcriptomic data for B. bassiana that include the cuticle penetration and hemocoel growth stages were analyzed for patterns (gene modules) of expression, yielding unique insights into these different life stages. These analyses integrate gene networks involved in fungal development, stress response and pathogenesis to further the systematic understanding of the global processes integral to the unique adaptation employed by fungal pathogens of insects.