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Insect outbreaks can cause large scale defoliation of forest trees or destruction of crops, leading to ecosystem degradation and economic losses. Some outbreaks occur simultaneously across large geographic scales and some outbreaks occur periodically every few years across space. Parasitoids are a natural enemy of these defoliators and could help mitigate these pest outbreaks. A holistic understanding of the host-parasitoid interactions in a spatial context would thus enhance our ability to understand, predict and prevent these outbreaks. We use a discrete time deterministic model of the host parasitoid system with populations migrating between 2 patches to elucidate features of spatial host outbreaks. We show that whenever populations persist indefinitely, host outbreaks in both patches can occur alternatively (out of phase) at low migration between patches whereas host outbreaks always occur simultaneously (in phase) in both patches at high migration between patches. We show that our results are robust across a large range of parameters across different modelling approaches used typically to model intraspecific competition among hosts and parasitism, in the host-parasitoid literature. We give an analytical expression for the period of oscillations when the migration is low i.e., when host outbreaks in both patches are out of phase, show it is in agreement with numerical results. We end our paper by showing that we get the same results whether we include the biologically rooted formulations from May et al. (1981) or a general cellular automata model with qualitative rules., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The protozoan parasites Plasmodium, Leishmania, and Trypanosoma are transmitted by hematophagous insects and cause severe diseases in humans. These infections pose a global threat, particularly in low-resource settings, and are increasingly extending beyond the current endemic regions. Tropism of parasites is crucial for their development, and recent studies have revealed colonization of noncanonical tissues, aiding their survival and immune evasion. Despite receiving limited attention, cumulative evidence discloses the respiratory system as a significant interface for host-pathogen interactions, influencing the course of (co)infection and disease onset. Due to its pathophysiological and clinical implications, we emphasize that further research is needed to better understand the involvement of the respiratory system and its potential to improve prevention, diagnosis, treatment, and interruption of the chain of transmission., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Insects are frequently infected with heritable bacterial endosymbionts. Some of them confer resistance to parasitoids. Such defensive symbionts are sensitive to variation in temperature. Drawing predominantly from the literature on aphids and flies, we show that temperature can affect the reliability of maternal transmission and the strength of protection provided by defensive symbionts. Costs of infection with defensive symbionts can also be temperature-dependent and may even turn into benefits under extreme temperatures, for example, when defensive symbionts increase heat tolerance. Alone or in combination, these mechanisms can drive temperature-associated (latitudinal) clines of infection prevalence with defensive symbionts. This has important consequences for host-parasitoid coevolution, as the relative importance of host-encoded vs. symbiont-provided defenses will shift along such clines., Competing Interests: Declaration of Competing Interest We declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This review focuses on biological control interactions in arid areas and is motivated by the need to devise sustainable agricultural practices for a warming and drying world. Parasitoids, important natural enemies of crop pests, are diverse and abundant in natural arid habitats. Dryland croplands, which are usually irrigated, are also rich in local parasitoids. Nevertheless, biological control projects in arid croplands mostly involve imported parasitoids (classical biological control) rather than the conservation of native species. Dryland parasitoids experience heat, drought, low relative humidity, sparse vegetation, and low host densities. Heat resistance combines local genetic adaptations, behavioral and physiological flexibility, and microbial symbioses, but how parasitoids cope with other aridity-related challenges is insufficiently understood. How dryland conditions impact host-parasitoid population dynamics also requires further study., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Ongoing climate change is increasing the frequency and magnitude of high-temperature events (HTEs), causing heat stress in parasitoids and their hosts. We argue that HTEs and heat stress should be viewed in terms of the intersecting life cycles of host and parasitoid. Recent studies illustrate how the biological consequences of a given HTE may vary dramatically depending on its timing within these lifecycles. The temperature sensitivity of host manipulation by parasitoids, and by viral endosymbionts of many parasitoids, can contribute to differing responses of hosts and parasitoids to HTEs. In some cases, these effects can result in reduced parasitoid success and increased host herbivory and may disrupt the ecological interactions between hosts and parasitoids. Because most studies to date involve endoparasitoids of aphid or lepidopteran hosts in agricultural systems, our understanding of heat responses of host-parasitoid interactions in natural systems is quite limited., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Anthropogenic climate change, including temperature extremes, is having a major impact on insect physiology, phenology, behavior, populations, and communities. Hyperparasitoids (insects whose offspring develop in, or on, the body of a primary parasitoid host) are expected to be especially impacted by such effects due to their typical life history traits (e.g. low fecundity and slow development), small populations (being high on the food chain), and cascading effects mediated via lower trophic levels. We review evidence for direct and indirect temperature and climate-related effects mediated via plants, herbivores, and the primary parasitoid host species on hyperparasitoid populations, focusing on higher temperatures. We discuss how hyperparasitoid responses may feed back to the community and affect biological control programs. We conclude that despite their great importance, very little is known about the potential effects of climate change on hyperparasitoids and make a plea for additional studies exploring such responses., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

In nature, most parasitoids attack more than one host species, and nearly all hosts are attacked by several species of parasitoids. This opens many potential opportunities for interactions of invasive species with native parasitoid-host association networks in invaded communities. Despite this, few studies have examined the direct and indirect impacts of biological invasion on parasitoid-host associations. This review examines what is known of these relationships from the most recent literature and suggests future research priorities. We conclude that parasitoid-host association networks in invaded communities are complex, dynamic, and subject to trophic intrusions from invasive plants, herbivores, plant pathogens, parasitoids, and hyperparasitoids. Future studies should take a holistic systems approach to understanding the impact of biological invasion and its consequences in shaping community structure through altering existing native, coevolved parasitoid-host association networks., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. No artifical intellegence assistance was used in writting, reviewing, and editing the manuscript., (Published by Elsevier Inc.)

The most important aim of the integrated management of forest insect pests remains the prevention of insect outbreaks, which are a consequence of the interaction of many factors in forest ecosystems, including species composition, age and health of the forest, soil type, the presence of natural enemies, and climatic factors. Integrated pest management until now has been achieved using measures aimed at shaping the functioning of stands in a changing environment. The aim of this review is to summarize research on the use of entomopathogens (microorganisms and nematodes) in the management of forest insect pests and to identify the principal knowledge gaps. We briefly describe the main research directions on the use of pathogens and nematodes to control insect pests and discuss limitations affecting their implementation. Research on entomopathogens for the biocontrol of forest insects has provided a wealth of knowledge that can be used effectively to reduce insect populations. Despite this, few entomopathogens are currently used in integrated pest management in forestry. They are applied in inoculation or inundation biocontrol strategies. While the use of entomopathogens in forest pest management shows great promise, practical implementation remains a distant goal. Consequently, sustainable reduction of forest pests, mainly native species, will be largely based on conservation biological control, which aims to modify the environment to favor the activity of natural enemies that regulate pest populations. This type of biocontrol can be supported by a range of silvicultural measures to increase the resilience of stands to insect infestations. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Parasitoids - insects that parasitize other insects - have fascinating biologies that have made them darlings of the science fiction genre, owing to their wide array of innovative and often gruesome strategies for living off other organisms. These insects do not sting, but rather lay eggs on or inside their hosts, typically another insect or spider. Unlike parasites, which feed off a host without killing it, parasitoids kill their hosts - and they typically do it slowly. Parasitoids carefully keep their hosts alive for extended periods while they feed on host hemolymph and/or tissues until they are close to completing their own development. The techniques parasitoids use to feed on and manipulate their hosts are wide ranging, demonstrating multiple evolutionary pathways to achieve successful development from egg to adult., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Trypanosomatids are obligatory parasites, some of which are responsible for important human and animal diseases, but the vast majority of trypanosomatids are restricted to invertebrate hosts. Isolation and in vitro cultivation of trypanosomatids from insect hosts enable their description, characterization, and subsequently genetic and genomic studies. However, exact nutritional requirements are still unknown for most trypanosomatids and thus very few defined media are available. This mini review provides information about the role of different ingredients, recommendations and advice on essential supplements and important physicochemical parameters of culture media with the aim of facilitating first attempts to cultivate insect-infesting trypanosomatids, with a focus on monoxenous trypanosomatids., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

Entomopathogenic nematodes (EPNs) are soil-dwelling parasitic roundworms commonly used as biocontrol agents of insect pests in agriculture. EPN dauer juveniles locate and infect a host in which they will grow and multiply until resource depletion. During their free-living stage, EPNs face a series of internal and environmental stresses. Their ability to overcome these challenges is crucial to determine their infection success and survival. In this review, we provide a comprehensive overview of EPN response to stresses associated with starvation, low/elevated temperatures, desiccation, osmotic stress, hypoxia, and ultra-violet light. We further report EPN defense strategies to cope with biotic stressors such as viruses, bacteria, fungi, and predatory insects. By comparing the genetic and biochemical basis of these strategies to the nematode model Caenorhabditis elegans, we provide new avenues and targets to select and engineer precision nematodes adapted to specific field conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Inc.)

The mass production of insects is rapidly expanding globally, supporting multiple industrial needs. However, parasite infections in insect mass-production systems can lower productivity and can lead to devastating losses. High rearing densities and artificial environmental conditions in mass-rearing facilities affect the insect hosts as well as their parasites. Environmental conditions such as temperature, gases, light, vibration, and ionizing radiation can affect productivity in insect mass-production facilities by altering insect development and susceptibility to parasites. This review explores the recent literature on environment-host-parasite interactions with a specific focus on mass-reared insect species. Understanding these complex interactions offers opportunities to optimise environmental conditions for the prevention of infectious diseases in mass-reared insects., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Trypanosoma cruzi is a digenetic unicellular parasite that alternates between a blood-sucking insect and a mammalian, host causing Chagas disease or American trypanosomiasis. In the insect gut, the parasite differentiates from the non-replicative trypomastigote forms that arrive upon blood ingestion to the non-infective replicative epimastigote forms. Epimastigotes develop into infective non-replicative metacyclic trypomastigotes in the rectum and are delivered via the feces. In addition to these parasite stages, transitional forms have been reported. The insect-feeding behavior, characterized by few meals of large blood amounts followed by long periods of starvation, impacts the parasite population density and differentiation, increasing the transitional forms while diminishing both epimastigotes and metacyclic trypomastigotes. To understand the molecular changes caused by nutritional restrictions in the insect host, mid-exponentially growing axenic epimastigotes were cultured for more than 30 days without nutrient supplementation (prolonged starvation). We found that the parasite population in the stationary phase maintains a long period characterized by a total RNA content three times smaller than that of exponentially growing epimastigotes and a distinctive transcriptomic profile. Among the transcriptomic changes induced by nutrient restriction, we found differentially expressed genes related to managing protein quality or content, the reported switch from glucose to amino acid consumption, redox challenge, and surface proteins. The contractile vacuole and reservosomes appeared as cellular components enriched when ontology term overrepresentation analysis was carried out, highlighting the roles of these organelles in starving conditions possibly related to their functions in regulating cell volume and osmoregulation as well as metabolic homeostasis. Consistent with the quiescent status derived from nutrient restriction, genes related to DNA metabolism are regulated during the stationary phase. In addition, we observed differentially expressed genes related to the unique parasite mitochondria. Finally, our study identifies gene expression changes that characterize transitional parasite forms enriched by nutrient restriction. The analysis of the here-disclosed regulated genes and metabolic pathways aims to contribute to the understanding of the molecular changes that this unicellular parasite undergoes in the insect vector., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Smircich, Pérez-Díaz, Hernández, Duhagon and Garat.)

Background: Trypanosomatid parasites are widely distributed in nature and can have a monoxenous or dixenous life-cycle. These parasites thrive in a wide number of insect orders, some of which have an important economic and environmental value, such as bees. The objective of this study was to develop a robust and sensitive real-time quantitative PCR (qPCR) assay for detecting trypanosomatid parasites in any type of parasitized insect sample., Methods: A TaqMan qPCR assay based on a trypanosomatid-conserved region of the α-tubulin gene was standardized and evaluated. The limits of detection, sensitivity and versatility of the α-tubulin TaqMan assay were tested and validated using field samples of honeybee workers, wild bees, bumblebees and grasshoppers, as well as in the human infective trypanosomatid Leishmania major., Results: The assay showed a detection limit of 1 parasite equivalent/µl and successfully detected trypanosomatids in 10 different hosts belonging to the insect orders Hymenoptera and Orthoptera. The methodology was also tested using honeybee samples from four apiaries (n = 224 worker honeybees) located in the Alpujarra region (Granada, Spain). Trypanosomatids were detected in 2.7% of the honeybees, with an intra-colony prevalence of 0% to 13%. Parasite loads in the four different classes of insects ranged from 40.6 up to 1.1 × 10 8 cell equivalents per host., Conclusions: These results show that the α-tubulin TaqMan qPCR assay described here is a versatile diagnostic tool for the accurate detection and quantification of trypanosomatids in a wide range of environmental settings., (© 2023. The Author(s).)

Parasite proliferations within/on the host form the basis of the outcome of all infectious diseases. However, within-host dynamics are difficult to study in vertebrates, as it requires regularly following pathogen proliferation from the start of the infection and at the organismal level. Invertebrate models allow for this monitoring under controlled conditions using population approaches. These approaches offer the possibility to describe many parameters of the within-host dynamics, such as rate of proliferation, probability to control the infection, and average time at which the pathogen is controlled. New parameters such as the Pathogen Load Upon Death and the Set-Point Pathogen Load have emerged to characterize within-host dynamics and better understand disease outcome. While contextualizing the potential of studying within-host dynamics in insects to build fundamental knowledge, we review what we know about within-host dynamics using insect models, and what it can offer to our knowledge of infectious diseases., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The prevalence and intensity of parasitism can have different fitness costs between sexes, and across species and developmental stages. This variation could arise because of species specific sexual and developmental differences in body condition, immunity, and resistance. Theory predicts that the prevalence of parasitism will be greater in individuals with poor body condition and the intensity of parasitism will be greater in individuals with larger body size. These predictions have been tested and verified in vertebrates. In insects, however, contradictory evidence has been found in different taxa. Here, we tested these predictions on two species of Agriocnemis (Agriocnemis femina and Agriocnemis pygmaea) damselflies, which are parasitized by Arrenurus water mite ectoparasites. We measured body weight, total body length, abdomen area and thorax area of non-parasitized damselflies and found body condition varied between males and females, between immature females and mature females and between A. femina and A. pygmaea. Then, we calculated the parasite prevalence, i.e., the absence or presence of parasites and intensity, i.e., the number of parasites per infected damselfly in eleven natural populations of both species. In line to our predictions, we observed greater prevalence in immature females than mature females but found no difference in parasite prevalence between males and females. Furthermore, we found that parasite intensity was higher in females than males and in immature females than mature females. Our result also showed that the frequency and intensity of parasitism varied between the two studied species, being higher in A. pygmaea than A. femina. Our study provides evidence that parasitism impacts sexes, developmental stages and species differentially and suggests that variation may occur due to sex, developmental stage, and species-specific resistance and tolerance mechanism., Competing Interests: The authors have declared that no competing interests exist.

Recent advances in insect-pathogen interactions have started to reveal the role of insect tissues and organs as natural infection routes for parasites and microbial pathogens. Here we summarize this information highlighting the micro- and macro-parasites that enter insects through distinct infection routes and link them to innate immune activity. We also examine whether the infection route determines the insect immune response and if the resulting immunological and physiological processes underpinning these different routes of infection are clearly distinct. Understanding how the infection route is associated with the robustness in insect host defense will help us identify conserved evolutionary and ecological patterns in order to design novel strategies for the management of destructive agricultural pests and disease vectors., (Copyright © 2022 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.)

Vertebrate-parasitic nematodes cause debilitating, chronic infections in millions of people worldwide. The burden of these so-called 'neglected tropical diseases' is often carried by poorer socioeconomic communities in part because research on parasitic nematodes and their vertebrate hosts is challenging and costly. However, complex biological and pathological processes can be modeled in simpler organisms. Here, we consider how insight into the interactions between entomopathogenic nematodes (EPN), their insect hosts and bacterial symbionts may reveal novel treatment targets for parasitic nematode infections. We argue that a combination of approaches that target nematodes, as well as the interaction of pathogens with insect vectors and bacterial symbionts, offer potentially effective, but underexplored opportunities.

Insect-associated microbes, including pathogens, parasites, and symbionts, influence the interactions of herbivorous insects and pollinators with their host plants. Moreover, herbivory-induced changes in plant resource allocation and defensive chemistry can influence pollinator behavior. This suggests that the outcomes of interactions between herbivores, their microbes and host plants could have implications for pollinators. As epizootic diseases occur at high population densities, pathogen and parasite-mediated effects on plants could have landscape-level impacts on foraging pollinators. The goal of this minireview is to highlight the potential for an herbivore's multitrophic interactions to trigger plant-mediated effects on the immunity and health of pollinators. We highlight the importance of plant quality and gut microbiomes in bee health, and how caterpillars as model herbivores interact with pathogens, parasites, and symbionts to affect plant quality, which forms the centerpiece of multitrophic interactions between herbivores and pollinators. We also discuss the impacts of other herbivore-associated factors, such as agricultural inputs aimed at decreasing herbivorous pests, on pollinator microbiomes., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The complex nature of climate change-mediated multitrophic interaction is an underexplored area, but has the potential to dramatically shift transmission and distribution of many insects and their pathogens, placing some populations closer to the brink of extinction. However, for individual insect-pathogen interactions climate change will have complicated hard-to-anticipate impacts. Thus, both pathogen virulence and insect host immunity are intrinsically linked with generalized stress responses, and in both pathogen and host have extensive trade-offs with nutrition (e.g., host plant quality), growth and reproduction. Potentially alleviating or exasperating these impacts, some pathogens and hosts respond genetically and rapidly to environmental shifts. This review identifies many areas for future research including a particular need to identify how altered global warming interacts with other environmental changes and stressors, and how consistent these impacts are across pathogens and hosts. With that achieved we would be closer to producing an overarching framework to integrate knowledge on all environmental interplay and infectious disease events., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Entomopathogenic nematodes (EPNs) have been successfully applied as biological control agents against above ground and soil stages of insect pests. However, for commercial application, it is crucial to mass culture these nematodes using in vitro liquid culture technology, as it is not attainable when using susceptible insects as hosts. Lobesia vanillana (Lepidoptera: Tortricidae) is regarded a sporadic pest of wine grapes in South Africa. The in vivo- and in vitro-cultured South African EPNs, Steinernema yirgalemense and Steinernema jeffreyense (Rhabditida: Steinernematidae), were evaluated against larvae and pupae of L. vanillana in laboratory bioassays. For larvae, high mortality was observed for all treatments: In vitro-cultured S. yirgalemense (98%) performed better than S. jeffreyense (73%), while within in vivo cultures, there was no difference between nematode species (both 83%). No significant difference was detected between in vivo- and in vitro cultures of the same nematode species. The LD50 of the in vitro-cultured S. yirgalemense, was 7.33 nematodes per larva. Mortality by infection was established by dissecting L. vanillana cadavers and confirming the presence of nematodes, which was > 90% for all treatments. Within in vitro cultures, both S. yirgalemense and S. jeffreyense were able to produce a new cohort of infective juveniles from L. vanillana larvae. Pupae, however, were found to be considerably less susceptible to EPN infection. This is the first study on the use of EPNs to control L. vanillana. The relative success of in vitro-cultured EPN species in laboratory assays, without any loss in pathogenicity, is encouraging for further research and development of this technology., Competing Interests: The authors have declared that no competing interests exist.

Taeniosis/cysticercosis and echinococcosis are neglected zoonotic helminth infections with high disease burden caused by tapeworms which circulate between definitive and intermediate host reflecting a predator-prey interaction. Taeniid eggs can remain vital for months, allowing arthropods to mechanically transport them to intermediate hosts. However, the multiple routes that arthropods provide as carriers of taeniid eggs are still often unregarded or not considered. This review focuses on the prevalence and importance of arthropods as carriers and spreaders of taeniid eggs in the epidemiology of taeniosis/cysticercosis and echinococcosis. Current scientific knowledge showed a relevant role of houseflies (Muscidae), blowflies (Calliphoridae), dung beetles (Scarabaeoidea), darkling beetles (Tenebrionidae), ground beetles (Carabidae) and skin beetles (Dermestidae) in the spread of taeniid eggs in the environment, which may favor the infection of new hosts through the direct ingestion of an insect or of contaminated food and water. At last, key research challenges are highlighted, illustrating that further knowledge on the topic is needed to develop and improve guidelines and actions to prevent taeniid infections worldwide., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this review, we summarize the current data on development of monoxenous trypanosomatids and phytomonads in various insects. Of these, Diptera and Hemiptera are the main host groups, and, consequently, most available information concerns their parasites. Within the insect body, the midgut and hindgut are the predominant colonization sites; in addition, some trypanosomatids can invade the foregut, Malpighian tubules, hemolymph, and/or salivary glands. Differences in the intestinal structure and biology of the host determine the variety of parasites' developmental and transmission strategies. Meanwhile, similar mechanisms are used by unrelated trypanosomatids, reflecting the limited range of options to achieve the same goal., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Insect parasitoids have evolved symbiotic interactions with several viruses and thousands of parasitoid species have established mutualistic associations with polydnaviruses (PDVs). While PDVs have often been described as virulence factors allowing development of immature parasitoids inside their herbivore hosts, there is increasing awareness that PDVs can affect plant-insect interactions. We review recent literature showing that PDVs alter not only host physiology, but also feeding patterns and composition of herbivore's oral secretions. In turn PDV-induced changes in herbivore phenotype affect plant responses to herbivory with consequences ranging from differential expression of plant defense-related genes to wider ecological effects across multiple trophic levels. In this opinion paper we also highlight important missing gaps to fully understand the role of PDVs and other parasitoid-associated viral symbionts in a plant-insect interaction perspective. Because PDVs negatively impact performance and survival of herbivore pests, we conclude arguing that PDV genomes offer potential opportunities for biological control., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In Arabidopsis (Arabidopsis thaliana), a hypersensitive-like response (HR-like response) is triggered underneath the eggs of the large white butterfly Pieris brassicae (P. brassicae), and this response is dependent on salicylic acid (SA) accumulation and signaling. Previous reports indicate that the clade I L-type LECTIN RECEPTOR KINASE-I.8 (LecRK-I.8) is involved in early steps of egg recognition. A genome-wide association study was used to better characterize the genetic structure of the HR-like response and discover loci that contribute to this response. We report here the identification of LecRK-I.1, a close homolog of LecRK-I.8, and show that two main haplotypes that explain part of the variation in HR-like response segregate among natural Arabidopsis accessions. Besides, signatures of balancing selection at this locus suggest that it may be ecologically important. Disruption of LecRK-I.1 results in decreased HR-like response and SA signaling, indicating that this protein is important for the observed responses. Furthermore, we provide evidence that LecRK-I.1 functions in the same signaling pathway as LecRK-I.8. Altogether, our results show that the response to eggs of P. brassicae is controlled by multiple LecRKs., (© American Society of Plant Biologists 2020. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Xenorhabdus nematophila bacteria are mutualists of Steinernema carpocapsae nematodes and pathogens of insects. Xenorhabdus nematophila exhibits phenotypic variation between insect virulence (V) and the mutualistic (M) support of nematode reproduction and colonization initiation in the infective juvenile (IJ) stage nematode that carries X. nematophila between insect hosts. The V and M phenotypes occur reciprocally depending on levels of the transcription factor Lrp: high-Lrp expressors are M+V- while low-Lrp expressors are V+M-. We report here that variable (wild type) or fixed high-Lrp expressors also are optimized, relative to low- or no-Lrp expressors, for colonization of additional nematode stages: juvenile, adult and pre-transmission infective juvenile (IJ). In contrast, we found that after the bacterial population had undergone outgrowth in mature IJs, the advantage for colonization shifted to low-Lrp expressors: fixed low-Lrp expressors (M-V+) and wild type (M+V+) exhibited higher average bacterial CFU per IJ than did high-Lrp (M+V-) or no-Lrp (M-V-) strains. Further, the bacterial population becomes increasingly low-Lrp expressing, based on expression of an Lrp-dependent fluorescent reporter, as IJs age. These data support a model that virulent X. nematophila have a selective advantage and accumulate in aging IJs in advance of exposure to insect hosts in which this phenotype is necessary., (© 2020 Society for Applied Microbiology and John Wiley & Sons Ltd.)

The over-prescription of antibiotics for treatment of infections is primarily to blame for the increase in bacterial resistance. Added to the problem is the slow rate at which novel antibiotics are discovered and the many processes that need to be followed to classify antimicrobials safe for medical use. Xenorhabdus spp. of the family Enterobacteriaceae, mutualistically associated with entomopathogenic nematodes of the genus Steinernema, produce a variety of antibacterial peptides, including bacteriocins, depsipeptides, xenocoumacins and PAX (peptide antimicrobial-Xenorhabdus) peptides, plus additional secondary metabolites with antibacterial and antifungal activity. The secondary metabolites of some strains are active against protozoa and a few have anti-carcinogenic properties. It is thus not surprising that nematodes invaded by a single strain of a Xenorhabdus species are not infected by other microorganisms. In this review, the antimicrobial compounds produced by Xenorhabdus spp. are listed and the gene clusters involved in synthesis of these secondary metabolites are discussed. We also review growth conditions required for increased production of antimicrobial compounds.

The global spread of a parasitic mite ( Varroa destructor) has resulted in Deformed wing virus (DWV), a previously rare pathogen, now dominating the viromes in honey bees and contributing to large-scale honey bee colony losses. DWV can be found in diverse insect taxa and has been implicated in spilling over from honey bees into associated ("apiary") and other ("non-apiary") insects. Here we generated next generation sequence data from 127 insect samples belonging to diverse taxa collected from Hawaiian islands with and without Varroa to identify whether the mite has indirectly affected the viral landscapes of key insect taxa across bees, wasps, flies and ants. Our data showed that, while Varroa was associated with a dramatic increase in abundance of (predominantly recombinant) DWV in honey bees (and no other honey bee-associated RNA virus), this change was not seen in any other taxa sampled. Honey bees share their environment with other insect populations and exist as a homogenous group, frequently sharing common viruses, albeit at low levels. Our data suggest that the threat of Varroa to increase viral load in an apiary does not automatically translate to an increase in virus load in other insects living in the wider community.

O -Acetylation of polysaccharides predominantly modifies plant cell walls by changing the physicochemical properties and, consequently, the structure and function of the cell wall. Expression regulation and specific function of cell wall-acetylating enzymes remain to be fully understood. In this report, we cloned a previously identified stunted growth mutant named sucrose uncoupled1 ( sun1 ) in Arabidopsis ( Arabidopsis thaliana ). SUN1 encodes a member of the TRICHOME BIREFRINGEN-LIKE family, AtTBL37 AtTBL37 is highly expressed in fast-growing plant tissues and encodes a Golgi apparatus-localized protein that regulates secondary cell wall thickening and acetylation. In sun1 , jasmonate signaling and expression of downstream chemical defense genes, including VEGETATIVE STORAGE PROTEIN1 and BRANCHED-CHAIN AMINOTRANSFERASE4 , are increased but, unexpectedly, sun1 is more susceptible to insect feeding. The central transcription factor in jasmonate signaling, MYC2, binds to and induces AtTBL37 expression. MYC2 also promotes the expression of many other TBLs Moreover, MYC activity enhances cell wall acetylation. Overexpression of AtTBL37 in the myc2-2 background reduces herbivore feeding. Our study highlights the role of O- acetylation in controlling plant cell wall properties, plant development, and herbivore defense., (© 2020 American Society of Plant Biologists. All Rights Reserved.)

Endosymbiotic bacteria that obligately associate with entomopathogenic nematodes as a complex are a unique model system to study competition. These nematodes seek an insect host and provide entry for their endosymbionts. Through their natural products, the endosymbionts nurture their nematodes by eliminating secondary infection, providing nutrients through bioconversion of the insect cadaver, and facilitating reproduction. On one hand, they cooperatively colonize the insect host and neutralize other opportunistic biotic threats. On the other hand, inside the insect cadaver as a fighting pit, they fiercely compete for the fittest partnership that will grant them the reproductive dominance. Here, we review the protective and nurturing nature of endosymbiotic bacteria for their nematodes and how their selective preference shapes the superior nematode-endosymbiont pairs as we know today., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Different model systems have, over the years, contributed to our current understanding of the molecular mechanisms underpinning the various types of interaction between bacteria and their animal hosts. The genus Photorhabdus comprises Gram-negative insect pathogenic bacteria that are normally found as symbionts that colonize the gut of the infective juvenile stage of soil-dwelling nematodes from the family Heterorhabditis . The nematodes infect susceptible insects and release the bacteria into the insect haemolymph where the bacteria grow, resulting in the death of the insect. At this stage the nematodes feed on the bacterial biomass and, following several rounds of reproduction, the nematodes develop into infective juveniles that leave the insect cadaver in search of new hosts. Therefore Photorhabdus has three distinct and obligate roles to play during this life-cycle: (1) Photorhabdus must kill the insect host; (2) Photorhabdus must be capable of supporting nematode growth and development; and (3) Photorhabdus must be able to colonize the gut of the next generation of infective juveniles before they leave the insect cadaver. In this review I will discuss how genetic analysis has identified key genes involved in mediating, and regulating, the interaction between Photorhabdus and each of its invertebrate hosts. These studies have resulted in the characterization of several new families of toxins and a novel inter-kingdom signalling molecule and have also uncovered an important role for phase variation in the regulation of these different roles.

Parasitoids depend on other insects for the development of their offspring. Their eggs are laid in or on a host insect that is consumed during juvenile development. Parasitoids harbor a diversity of microbial symbionts including viruses, bacteria, and fungi. In contrast to symbionts of herbivorous and hematophagous insects, parasitoid symbionts do not provide nutrients. Instead, they are involved in parasitoid reproduction, suppression of host immune responses, and manipulation of the behavior of herbivorous hosts. Moreover, recent research has shown that parasitoid symbionts such as polydnaviruses may also influence plant-mediated interactions among members of plant-associated communities at different trophic levels, such as herbivores, parasitoids, and hyperparasitoids. This implies that these symbionts have a much more extended phenotype than previously thought. This review focuses on the effects of parasitoid symbionts on direct and indirect species interactions and the consequences for community ecology.

Entomopathogenic nematodes are parasitic organisms with an exceptional capacity to infect rapidly and efficiently a wide range of insect species. Their distinct pathogenic properties have established entomopathogenic nematodes as supreme biocontrol agents of insects as well as excellent models to simulate and dissect the molecular and physiological bases of conserved strategies employed by parasitic nematodes that cause infectious diseases in humans. The extreme infectivity of entomopathogenic nematodes is due in part to the presence of certain species of Gram-negative bacteria that live in mutualistic symbiosis during the infective juvenile stage, which forms the central part of the nematode life cycle. Both nematodes and their mutualistic bacteria are capable of interfering and undermining several aspects of the insect host innate immune system during the infection process. The mutualistic bacteria are also able to modulate other biological functions in their nematode host including growth, development, and reproduction. In this review, we will focus our attention on the mutualistic relationship between entomopathogenic nematodes and their associated bacteria to discuss the nature and distinct characteristics of the regulatory mechanisms, and their molecular as well as physiological components that control this specific biological partnership.

Tobacco is one of the major industrial crops cultivated worldwide. Chemical control is the main method employed to reduce damage by insect pests. The use of entomopathogenic fungi represents an alternative to replace insecticides. The search for effective strains in the field constitutes a first step when developing a formulation. The objective of this work was to study genetic differences among isolates of entomopathogenic fungi obtained from tobacco grown soils using ISSR markers. The pathogenicity of the strains towards Helicoverpa gelotopoeon and Diabrotica speciosa was also assessed in order to search for a relationship between virulence and genetic diversity. Nineteen isolates were identified according to morphological features and molecular techniques as Beauveria bassiana (11) and Purpureocillium lilacinum (8). The diversity tree generated by ISSR analysis showed a high diversity among the strains. The pathogenicity towards H. gelotopoeon and D. speciosa was assessed and the logistic models generated showed that B. bassiana isolates LPSc1215 and LPSc1364 were the most pathogenic against both insect pests tested. In the diversity tree, these strains were grouped in a same cluster with a similarity level of approximately 85%, indicating a possible relationship between virulence and the band pattern generated.

Monoxenous (one host) trypanosomatids from insects and other invertebrates can be introduced into axenic culture relatively easily and efficiently, allowing for their transfer from the field into the laboratory. Here we describe simple methods and alternative cultivation protocols, the wider application of which will allow substantial expansion of trypanosomatids available for research.

Mass spectrometry based proteomics allows for the identification and quantification of protein and phosphorylation site abundance on a proteome wide scale. Here we describe the metabolic labeling of cultured Trypanosoma brucei cells in either the bloodstream or procyclic life cycle stage using stable isotope labeling of amino acids in cell culture (SILAC), and the production of samples suitable for analysis by liquid chromatography tandem mass spectrometry. The protocols require little specialist equipment, and they typically enable quantification of over 4500 proteins and 9000 phosphorylation sites.

The extreme biological diversity of Oceanian archipelagos has long stimulated research in ecology and evolution. However, parasitic protists in this geographic area remained neglected and no molecular analyses have been carried out to understand the evolutionary patterns and relationships with their hosts. Papua New Guinea (PNG) is a biodiversity hotspot containing over 5% of the world's biodiversity in less than 0.5% of the total land area. In the current work, we examined insect heteropteran hosts collected in PNG for the presence of trypanosomatid parasites. The diversity of insect flagellates was analysed, to our knowledge for the first time, east of Wallace's Line, one of the most distinct biogeographic boundaries of the world. Out of 907 investigated specimens from 138 species and 23 families of the true bugs collected in eight localities, 135 (15%) were infected by at least one trypanosomatid species. High species diversity of captured hosts correlated with high diversity of detected trypanosomatids. Of 46 trypanosomatid Typing Units documented in PNG, only eight were known from other geographic locations, while 38 TUs (~83%) have not been previously encountered. The widespread trypanosomatid TUs were found in both widely distributed and endemic/sub-endemic insects. Approximately one-third of the endemic trypanosomatid TUs were found in widely distributed hosts, while the remaining species were confined to endemic and sub-endemic insects. The TUs from PNG form clades with conspicuous host-parasite coevolutionary patterns, as well as those with a remarkable lack of this trait. In addition, our analysis revealed new members of the subfamilies Leishmaniinae and Strigomonadinae, potentially representing new genera of trypanosomatids., (Copyright © 2019 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.)

Current understanding of flagellum/cilium length regulation focuses on a few model organisms with flagella of uniform length. Leptomonas pyrrhocoris is a monoxenous trypanosomatid parasite of firebugs. When cultivated in vitro , L. pyrrhocoris duplicates every 4.2 ± 0.2 h, representing the shortest doubling time reported for trypanosomatids so far. Each L. pyrrhocoris cell starts its cell cycle with a single flagellum. A new flagellum is assembled de novo , while the old flagellum persists throughout the cell cycle. The flagella in an asynchronous L. pyrrhocoris population exhibited a vast length variation of ∼3 to 24 μm, casting doubt on the presence of a length regulation mechanism based on a single balance point between the assembly and disassembly rate in these cells. Through imaging of live L. pyrrhocoris cells, a rapid, partial disassembly of the existing, old flagellum is observed upon, if not prior to, the initial assembly of a new flagellum. Mathematical modeling demonstrated an inverse correlation between the flagellar growth rate and flagellar length and inferred the presence of distinct, cell cycle-dependent disassembly mechanisms with different rates. On the basis of these observations, we proposed a min-max model that could account for the vast flagellar length range observed for asynchronous L. pyrrhocoris. This model may also apply to other flagellated organisms with flagellar length variation. IMPORTANCE Current understanding of flagellum biogenesis during the cell cycle in trypanosomatids is limited to a few pathogenic species, including Trypanosoma brucei , Trypanosoma cruzi , and Leishmania spp. The most notable characteristics of trypanosomatid flagella studied so far are the extreme stability and lack of ciliary disassembly/absorption during the cell cycle. This is different from cilia in Chlamydomonas and mammalian cells, which undergo complete absorption prior to cell cycle initiation. In this study, we examined flagellum duplication during the cell cycle of Leptomonas pyrrhocoris With the shortest duplication time documented for all Trypanosomatidae and its amenability to culture on agarose gel with limited mobility, we were able to image these cells through the cell cycle. Rapid, cell cycle-specific flagellum disassembly different from turnover was observed for the first time in trypanosomatids. Given the observed length-dependent growth rate and the presence of different disassembly mechanisms, we proposed a min-max model that can account for the flagellar length variation observed in L. pyrrhocoris ., (Copyright © 2019 He et al.)

Mermithids (phylum Nematoda) and hairworms (phylum Nematomorpha) somehow drive their arthropod hosts into water, which is essential for the worms' survival after egression. The mechanisms behind this behavioural change have been investigated in hairworms, but not in mermithids. Establishing a similar mechanistic basis for host behavioural change between these two distantly related parasitic groups would provide strong convergent evidence for adaptive manipulation and insight into how these parasites modify and/or create behaviour. Here, we search for this convergence, and also contrast changes in physiology between hosts infected with immature and mature mermithids to provide the first ontogenetic evidence for adaptive manipulation by disentangling host response and pathology from the parasite's apparent manipulative effects. We used SWATH-mass spectrometry on brains of Forficula auricularia (earwig) and Bellorchestia quoyana (sandhopper), infected with the mermithids Mermis nigrescens and Thaumamermis zealandica , respectively, at both immature and mature stages of infection, to quantify proteomic changes resulting from mermithid infection. Across both hosts (and hairworm-infected hosts, from earlier studies), the general function of dysregulated proteins was conserved. Proteins involved in energy generation/mobilization were dysregulated, corroborating reports of erratic/hyperactive behaviour in infected hosts. Dysregulated proteins involved in axon/dendrite and synapse modulation were also common to all hosts, suggesting neuronal manipulation is involved in inducing positive hydrotaxis. Furthermore, downregulation of CamKII and associated proteins suggest manipulation of memory also contributes to the behavioural shift.

The defence reactions of insects to parasitic invaders are both varied and complex. Melanisation of pathogens is often an important step in insect immunity and can play a key role in isolating parasites. Within samples collected from a subalpine stream in New Zealand during two consecutive seasons (i.e., winter and spring), we observed and categorised different levels of melanotic encapsulation by aquatic insect larvae to dormant Gordius sp. hairworm (Phylum Nematomorpha) cysts, a relatively obscure group of parasites. Some of these insect species act as intermediate transport hosts in the complex life cycle of hairworms. Based on these new observations, we calculated the melanisation response for an abundant species of caddisfly larvae (Olinga sp.) using the proportion of non-melanised cysts per individual host. We tested the hypothesis that season and total number of cysts in an infected host impact its melanisation response. Also, we explored the effect of host body size on the total number of cysts it carries. We found that the total number of cysts does not affect the melanisation response of the host. Season did have an impact on the melanisation response in Olinga sp., with lower levels observed in the spring. Additionally, larger caddisfly larvae harboured more cysts than smaller ones. Since little is known about the cryptic interactions between hairworms and their intermediate hosts, this new information adds some complexity to this poorly understood group of parasites., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Certain species of parasites have the apparent ability to alter the behaviour of their host in order to facilitate the completion of their own life cycle. While documented in hairworms (phylum Nematomorpha), the ability for mermithid parasites (from the sister phylum Nematoda) to force hosts to enter water remains more enigmatic. Here, we present the first experimental evidence in a laboratory setting that an insect which normally never enters open water (the European earwig Forficula auricularia) will readily enter the water when infected with a mermithid nematode (Mermis nigrescens). Only adult mermithids appear capable of inducing this polarising shift in behaviour, with mermithid length being a very strong predictor of whether their host enters water. However, mermithid length was only weakly associated with how long it took an earwig to enter water following the beginning of a trial. Considering the evidence presented here and its alignment with a proteomic investigation on the same host-parasite system, this study provides strong evidence for adaptive behavioural manipulation and a foundational system for further behavioural and mechanistic exploration.

Many animals depend on microbial symbionts to provide nutrition, defence or other services. Holometabolous insects, as well as other animals that undergo metamorphosis, face unique constraints on symbiont maintenance. Microbes present in larvae encounter a radical transformation of their habitat and may also need to withstand chemical and immunological challenges. Metamorphosis also provides an opportunity, in that symbiotic associations can be decoupled over development. For example, some holometabolous insects maintain the same symbiont as larvae and adults, but house it in different tissues; in other species, larvae and adults may harbour entirely different types or numbers of microbes, in accordance with shifts in host diet or habitat. Such flexibility may provide an advantage over hemimetabolous insects, in which selection on adult-stage microbial associations may be constrained by its negative effects on immature stages, and vice versa. Additionally, metamorphosis itself can be directly influenced by symbionts. Across disparate insect taxa, microbes protect hosts from pathogen infection, supply nutrients essential for rebuilding the adult body and provide cues regulating pupation. However, microbial associations remain completely unstudied for many families and even orders of Holometabola, and future research will undoubtedly reveal more links between metamorphosis and microbiota, two widespread features of animal life. This article is part of the theme issue 'The evolution of complete metamorphosis'.

Xenorhabdus spp., entomopathogenic bacteria symbiotically associated with the nematodes of the Steinernematid family, are known to produce several toxic proteins that interfere with the cellular immune responses of insects. In order to identify novel cytotoxins from Xenorhabdus spp., a fosmid library of X. stockiae HN_xs01 strain was constructed and the cytotoxicity of fosmid clones was tested against insect midgut CF-203 cells. An FS2 clone bearing the srfABC operon, originally identified in Salmonella enterica, exhibited excellent cytotoxicity against CF-203 cells. The srfABC operon alone exhibited cytotoxic effects and all three components of SrfABC toxin were essential for full cytotoxicity. Immunofluorescence studies showed that SrfABC toxin could depolymerize microtubules and disrupt mitochrondria. Flow cytometer analysis demonstrated that SrfABC toxin significantly induced G2/M phase arrest and apoptosis in CF-203 cells. Furthermore, SrfABC toxin exhibits highly injectable insecticidal activity against Helicoverpa armigera larvae. As is often found in host-associated microorganisms, SrfABC toxin is thought to play an important role in host colonization., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Insect phenology is affected by climate change and main responses are driven by phenotypic plasticity and evolutionary changes. Any modification in seasonal activity in one species can have consequences on interacting species, within and among trophic levels. In this overview, we focus on synchronisation mismatches that can occur between tightly interacting species such as hosts and parasitoids or preys and predators. Asynchronies happen because species from different trophic levels can have different response rates to climate change. We show that insect species alter their seasonal activities by modifying their life-cycle through change in voltinism or by altering their development rate. We expect strong bottom-up effects for phenology adjustments rather than top-down effects within food-webs. Extremely complex outcomes arise from such trophic mismatches, which make consequences at the community or ecosystem levels tricky to predict in a climate change context. We explore a set of potential consequences on population dynamics, conservation of species interactions, with a particular focus on the provision of ecosystem services by predators and parasitoids, such as biological pest control., (Copyright © 2019. Published by Elsevier Inc.)

From 1 January 2018 came into force Regulation (EU) 2015/2238 of the European Parliament and of the Council of 25 November 2015, introducing the concept of "novel foods", including insects and their parts. One of the most commonly used species of insects are: mealworms (Tenebrio molitor), house crickets (Acheta domesticus), cockroaches (Blattodea) and migratory locusts (Locusta migrans). In this context, the unfathomable issue is the role of edible insects in transmitting parasitic diseases that can cause significant losses in their breeding and may pose a threat to humans and animals. The aim of this study was to identify and evaluate the developmental forms of parasites colonizing edible insects in household farms and pet stores in Central Europe and to determine the potential risk of parasitic infections for humans and animals. The experimental material comprised samples of live insects (imagines) from 300 household farms and pet stores, including 75 mealworm farms, 75 house cricket farms, 75 Madagascar hissing cockroach farms and 75 migrating locust farms. Parasites were detected in 244 (81.33%) out of 300 (100%) examined insect farms. In 206 (68.67%) of the cases, the identified parasites were pathogenic for insects only; in 106 (35.33%) cases, parasites were potentially parasitic for animals; and in 91 (30.33%) cases, parasites were potentially pathogenic for humans. Edible insects are an underestimated reservoir of human and animal parasites. Our research indicates the important role of these insects in the epidemiology of parasites pathogenic to vertebrates. Conducted parasitological examination suggests that edible insects may be the most important parasite vector for domestic insectivorous animals. According to our studies the future research should focus on the need for constant monitoring of studied insect farms for pathogens, thus increasing food and feed safety., Competing Interests: The authors have declared that no competing interests exist.

Microbial pesticides based on bacteria, fungi and viruses or their bioactive compounds have long been developed as alternatives for synthetic pesticides to control invertebrate pests. However, concern for environmental and human health from excessive reliance on chemical pesticides, changes in residue standards, and increased demand for organically grown produce has contributed to a considerable growth in their use in recent years. There are currently 356 registered biopesticide active ingredients in the U.S., including 57 species and/or strains of microbes or their derivatives, labelled for use against pestiferous insects, mites and nematodes. Strains of Bacillus thuringiensis for Lepidoptera remain the most popular products, but newer bacterial strains and their metabolites have been developed against a wider range of arthropods for use on fruit, vegetable and ornamental crops. Currently, ten fungal species/strains are registered against thrips, whiteflies, aphids, or other sucking pests and plant parasitic nematodes in greenhouse, nursery and field crops, while five nucleopolyhedroviruses and three granuloviruses are registered for Lepidoptera in field and greenhouse grown vegetables and ornamentals, tree fruit and nuts, forestry, and stored products. Many of these products are organic listed and most have 4 h or less reentry and no pre-harvest restrictions. Investment by multinational companies, advances in screening, industrial fermentation and storage of new microorganisms, are increasing the market share for microbials. Here, we summarize the market for microbial-based pesticides labelled for invertebrates in the U.S. We cover current uses and recent advances that further advance their use in additional markets in the coming decades., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Biopesticides are needed for control of endemic and invasive pests impacting New Zealand's primary sectors including pests that are emerging as a result of climate change and farming intensification. Products developed in New Zealand are usually based on endemic strains of microorganisms, including new species/strains with novel modes of action. For example, Invade and BioShield were developed using endemic strains of the bacterium Serratia entomophila, for use in New Zealand only. To date, most of these home-grown products have either struggled for market share or have remained in small niche markets. However, the number of products registered for use has been steadily increasing in response to consumer demand. Factors limiting past use of biopesticides in New Zealand include market size, registration costs and limited efficacy over a range of climatic zones. Many promising new agents are currently under development as biopesticides with international applications and the launch of several new start-up companies suggests a brighter future for biopesticide use in New Zealand., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The biopesticide industry in India is undergoing rapid change, reflecting increased global trade in agricultural commodities, a changing regulatory environment and evolving consumer preferences. Currently biopesticides comprise ≈ 5% of the Indian pesticide market, with at least 15 microbial species and 970 microbial formulations registered through the Central Insecticides Board and Registration Committee (CIBRC). As of 2017, over 200 products based on entomopathogenic fungi (Beauveria bassiana, B. brongniartii, Metarhizium anisopliae s.l., Lecanicillium lecanii and Hirsutella thompsonii) and nematicidal fungi (Purpureocillium lilacinum and Pochonia chlamydosporia) are registered for use against various arthropods and plant parasitic nematodes. Regarding bacteria, over 30 products based on Bacillus thuringiensis (Bt) subsp. kurstaki are registered against bollworms, loopers and other lepidopterans, while 12 based on Bt subsp. israelensis and three with Bt subsp. sphaericus have been used against mosquitoes. Two viruses are registered, namely Helicoverpa armigera nucleopolyhedrovirus (22 products) and Spodoptera litura nucleopolyhedrovirus (5 products) for use against bollworms and armyworms. Four entomopathogenic nematode species are sold in Indian market. These include long-lasting wettable powder formulations of Heterorhabditis indica developed by the ICAR-National Bureau of Agricultural Insect Resources, Bengaluru which have been distributed on a large scale to control white grubs and other sugarcane pests. Biopesticide research on the subcontinent is at a relatively early stage, but evolving rapidly, and focusing on indigenous entomopathogens. Despite onerous regulation, quality-control issues and limited large-scale production facilities, investment in domestic fermentation technologies, improved delivery systems, and promotion of biological control through private and public initiative will increase the share of microbial biopesticides in the country., (Copyright © 2018 Elsevier Inc. All rights reserved.)