Ecotoxicological effects of commercial herbicides on the reproductive system of aquatic arthropod Limnocoris submontandoni (Hemiptera: Naucoridae) / Efeitos ecotoxicológicos de herbicidas comerciais no sistema reprodutivo do artrópode aquático Limnocoris submontandoni (Hemiptera: Naucoridae)

Abstract Worldwide, conventional agriculture makes extensive use of pesticides. Although the effects of herbicides are relatively well known in terms of environmental impacts on non-target organisms, there is very little scientific evidence regarding the impacts of herbicide residues on aquatic arthropods from tropical conservation areas. This study evaluates for the first time the toxicity of the herbicides ametryn, atrazine, and clomazone on the aquatic insect Limnocoris submontandoni (Hemiptera: Naucoridae). The lethal concentration (LC50) of herbicides was evaluated for these insects, as well as the effect of the herbicides on the insects' tissues and testicles. The estimated LC50 was 1012.41, 192.42, and 46.09 mg/L for clomazone, atrazine, and ametryn, respectively. Spermatocyte and spermatid changes were observed under the effect of atrazine, and effects on spermatogenesis were observed for some concentrations of clomazone, with apparent recovery after a short time. Our results provide useful information on the effects of herbicide residues in aquatic systems. This information can help minimize the risk of long-term reproductive effects in non-target species that have been previously overlooked in ecotoxicology studies.

Resumo Em todo o mundo, a agricultura convencional faz uso extensivo de pesticidas. Embora os efeitos dos herbicidas sejam relativamente bem conhecidos em termos de impactos ambientais em organismos não-alvo, há pouca evidência científica sobre os impactos de resíduos de herbicidas em artrópodes aquáticos de áreas de conservação tropicais. Este estudo avalia pela primeira vez a toxicidade dos herbicidas ametryn, atrazine e clomazone sobre o inseto aquático Limnocoris submontandoni (Hemiptera: Naucoridae). A concentração letal (LC50) de herbicidas foi avaliada para esses insetos, bem como o efeito dos herbicidas nos tecidos e testículos dos insetos. A LC50 estimada foi de 1012,41, 192,42 e 46,09 mg/L para clomazone, atrazine e ametryn, respectivamente. Alterações nos espermatócitos e espermátides foram observadas sob o efeito de atrazine, e efeitos na espermatogênese foram observados para algumas concentrações de clomazone, com aparente recuperação após um curto período de tempo. Nossos resultados fornecem informações úteis sobre os efeitos de resíduos de herbicidas em sistemas aquáticos. Essas informações podem ajudar a minimizar o risco de efeitos reprodutivos de longo prazo em espécies não-alvo que foram negligenciadas anteriormente em estudos de ecotoxicologia.

Monocrotaline presence in the Crotalaria (Fabaceae) plant genus and its influence on arthropods in agroecosystems / Presença de monocrotalina em plantas do gênero Crotalaria (Fabaceae) e a sua influência sobre artrópodes nos agroecossistemas

Abstract Crotalaria (Fabaceae) occurs abundantly in tropical and subtropical regions and has about 600 known species. These plants are widely used in agriculture, mainly as cover plants and green manures, in addition to their use in the management of phytonematodes. A striking feature of these species is the production of pyrrolizidine alkaloids (PAs), secondary allelochemicals involved in plant defense against herbivores. In Crotalaria species, monocrotaline is the predominant PA, which has many biological activities reported, including cytotoxicity, tumorigenicity, hepatotoxicity and neurotoxicity, with a wide range of ecological interactions. Thus, studies have sought to elucidate the effects of this compound to promote an increase in flora and fauna (mainly insects and nematodes) associated with agroecosystems, favoring the natural biological control. This review summarizes information about the monocrotaline, showing such effects in these environments, both above and below ground, and their potential use in pest management programs.

Resumo Crotalaria (Linnaeus, 1753) (Fabaceae) ocorre abundantemente em regiões tropicais e subtropicais e tem cerca de 600 espécies conhecidas. Estas plantas são amplamente utilizadas na agricultura, principalmente como cobertura e adubos verdes, além da sua utilização no manejo de fitonematoides. Uma característica marcante destas espécies é a produção de alcalóides pirrolizidinicos (APs), aleloquímicos secundários envolvidos na defesa das plantas contra os herbívoros. Nas espécies de Crotalaria, a monocrotalina é a AP predominante, que tem muitas atividades biológicas relatadas, incluindo citotoxicidade, tumorigenicidade, hepatotoxicidade e neurotoxicidade, além de uma vasta gama de interações ecológicas. Assim, estudos têm procurado elucidar os efeitos desse composto para promover um incremento na flora e fauna (principalmente insetos e nematoides) associados aos agroecossistemas, favorecendo o controle biológico natural. Esta revisão compila informações sobre a monocrotalina, mostrando tais efeitos nesses ambientes, tanto acima como abaixo do solo e a sua potencial utilização em programas de manejo de pragas.

Do arthropods and diseases affect the production of fruits on Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae)? / Artrópodes e doenças afetam a produção de frutos em Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae)?

Frequencies, magnitudes, and distributions of occurrence can affect the events. The problem can be worse or the solution better if greater frequencies and magnitudes are presented with aggregated distribution in the production system. Indices, hence, are used to assist in decision-making on certain issues. The system formed by Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae), a typical and economically important Brazilian Cerrado tree species, and its several arthropods are adequate to evaluate a new index. This study aimed to test an index to identify the loss and solution sources and their importance in the system's loss or income gain. The index is: Percentage of Importance Indice [...] separated the loss sources [e.g., Edessa rufomarginata De Geer, 1773 (Hemiptera: Pentatomidae) on fruits = 41.90%)] on the percentage of reduction of fruit production (e.g., 0.13%), calculated the attention level (e.g., 0.10/fruit), with a total lost production of 1.35% (≈ 307 total lost fruits). The % I.I. also separated the solution sources [e.g., Zelus armillatus (Lep. and Servi., 1825) (Hemiptera: Reduviidae) = 55.48%), the non-attention level (e.g., Z. armillatus: 0.394 for E. rufomarginata on fruit), with total income gain of 0.56% (≈ 128 total saved fruits) on the natural system (e.g., C. brasiliense trees). This index can calculate losses or the effectiveness of the solutions monetarily. Here I test the % I.I., an index that can detect the key loss and solution sources on the system, which can be applied in some knowledge areas.

Frequências, magnitudes e distribuição de ocorrência pode afetar os eventos. O problema pode ser pior ou a solução melhor se maiores frequências e magnitudes forem apresentadas com distribuição agregada no sistema de produção. Índices, então, são usados para assistir na decisão de certas questões. O sistema formado pelo Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae), uma espécie arbórea típica e economicamente importante do Cerrado brasileiro, e seus diversos artrópodes são adequados para avaliar um novo índice. A motivação deste trabalho foi testar um índice capaz de identificar as fontes de perda e de soluções, e suas importâncias em termos de perdas ou ganhos no sistema. O índice é: percentagem de importância [...] separou as fontes de perda [ex., Edessa rufomarginata De Geer, 1773 (Hemiptera: Pentatomidae) em frutos = 41,90%)] na percentagem de redução na produção de frutos (ex., 0,13%), calculando o nível de atenção (ex., 0,10/fruto), com um total de perda de produção de 1,35% (≈ 307 frutos totais perdidos). O % I.I. também separou as fontes de solução [ex., Zelus armillatus (Lep. and Servi., 1825) (Hemiptera: Reduviidae) = 55,48%)], o nível de não atenção (ex., Z. armillatus: 0,394 para E. rufomarginata em fruto), com total de ganho de 0,56% (≈ 128 total de frutos salvos) no sistema natural (ex., árvores de C. brasiliense). Esse índice pode calcular essas perdas ou a eficácia das soluções monetariamente. Aqui eu testo o % I.I., um índice capaz de detectar fatores chaves de perda e de soluções no sistema, capaz de ser aplicado em algumas áreas do conhecimento.

ICTV Virus Taxonomy Profile: Phenuiviridae 2023.

The family Phenuiviridae comprises viruses with 2-8 segments of negative-sense or ambisense RNA, comprising 8.1-25.1 kb in total. Virions are typically enveloped with spherical or pleomorphic morphology but can also be non-enveloped filaments. Phenuivirids infect animals including livestock and humans, birds, plants or fungi, as well as arthropods that serve as single hosts or act as biological vectors for transmission to animals or plants. Phenuivirids include important pathogens of humans, livestock, seafood and agricultural crops. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Phenuiviridae, which is available at ictv.global/report/phenuiviridae.

Larvicidal activity of Stemona collinsiae root extract against Musca domestica and Chrysomya megacephala.

Musca domestica and Chrysomya megacephala, considered synanthropic insects, are medically important flies, as they transmit vector-borne diseases to humans and animals. In Thailand, Stemona (Stemonaceae) plants have been traditionally used as insecticides. This study was designed to determine the larvicidal activity of S. collinsiae root extract against M. domestica and C. megacephala larvae. A 70% ethanol crude extract from S. collinsiae roots was tested against the third-instar larvae of both species using direct and indirect contact methods. The development and mortality rates of the insects were observed, and the LC values were calculated. The extract caused irregular development in both species, shown as segmental puparia that could not emerge as adult flies. The LC50 values of the extract against M. domestica tested by direct and indirect contact methods were 0.0064 ± 0.0005 mg/larva and 0.0165 ± 0.0002 mg/cm2/larva, respectively. In the case of C. megacephala, the LC50 value determined by the indirect contact method was 1.0500 ± 0.0001 mg/cm2/larva. The ethanolic root extract of S. collinsiae was able to kill the larvae of both species after dermal administration. It is of interest to develop S. collinsiae root extract as a natural fly control biopesticide.

Genome-wide DNA methylation patterns in bumble bee (Bombus vosnesenskii) populations from spatial-environmental range extremes.

Unraveling molecular mechanisms of adaptation to complex environments is crucial to understanding tolerance of abiotic pressures and responses to climatic change. Epigenetic variation is increasingly recognized as a mechanism that can facilitate rapid responses to changing environmental cues. To investigate variation in genetic and epigenetic diversity at spatial and thermal extremes, we use whole genome and methylome sequencing to generate a high-resolution map of DNA methylation in the bumble bee Bombus vosnesenskii. We sample two populations representing spatial and environmental range extremes (a warm southern low-elevation site and a cold northern high-elevation site) previously shown to exhibit differences in thermal tolerance and determine positions in the genome that are consistently and variably methylated across samples. Bisulfite sequencing reveals methylation characteristics similar to other arthropods, with low global CpG methylation but high methylation concentrated in gene bodies and in genome regions with low nucleotide diversity. Differentially methylated sites (n = 2066) were largely hypomethylated in the northern high-elevation population but not related to local sequence differentiation. The concentration of methylated and differentially methylated sites in exons and putative promoter regions suggests a possible role in gene regulation, and this high-resolution analysis of intraspecific epigenetic variation in wild Bombus suggests that the function of methylation in niche adaptation would be worth further investigation.

A detoxification pathway initiated by a nuclear receptor TcHR96h in Tetranychus cinnabarinus (Boisduval).

Understanding the mechanism of detoxification initiation in arthropods after pesticide exposure is crucial. Although the identity of transcription factors that induce and regulate the expression of detoxification genes in response to pesticides is beginning to emerge, whether transcription factors directly interact with xenobiotics is unclear. The findings of this study revealed that a nuclear hormone receptor, Tetranychus cinnabarinus hormone receptor (HR) TcHR96h, regulates the overexpression of the detoxification gene TcGSTm02, which is involved in cyflumetofen resistance. The nuclear translocation of TcHR96h increased after cyflumetofen exposure, suggesting direct binding with cyflumetofen. The direct binding of TcHR96h and cyflumetofen was supported by several independent proteomic assays that quantify interactions with small molecules. Together, this study proposes a model for the initiation of xenobiotic detoxification in a polyphagous agricultural pest. These insights not only provide a better understanding of the mechanisms of xenobiotic detoxification and metabolism in arthropods, but also are crucial in understanding adaptation in polyphagous herbivores.

The macrophage genetic cassette inr/dtor/pvf2 is a nutritional status checkpoint for developmental timing.

A small number of signaling molecules, used reiteratively, control differentiation programs, but the mechanisms that adapt developmental timing to environmental cues are less understood. We report here that a macrophage inr/dtor/pvf2 genetic cassette is a developmental timing checkpoint in Drosophila, which either licenses or delays biosynthesis of the steroid hormone in the endocrine gland and metamorphosis according to the larval nutritional status. Insulin receptor/dTor signaling in macrophages is required and sufficient for production of the PDGF/VEGF family growth factor Pvf2, which turns on transcription of the sterol biosynthesis Halloween genes in the prothoracic gland via its receptor Pvr. In response to a starvation event or genetic manipulation, low Pvf2 signal delays steroid biosynthesis until it becomes Pvr-independent, thereby prolonging larval growth before pupariation. The significance of this developmental timing checkpoint for host fitness is illustrated by the observation that it regulates the size of the pupae and adult flies.

Recent advances in insect thermoregulation.

Ambient temperature (Ta) is a critical abiotic factor for insects that cannot maintain a constant body temperature (Tb). Interestingly, Ta varies during the day, between seasons and habitats; insects must constantly cope with these variations to avoid reaching the deleterious effects of thermal stress. To minimize these risks, insects have evolved a set of physiological and behavioral thermoregulatory processes as well as molecular responses that allow them to survive and perform under various thermal conditions. These strategies range from actively seeking an adequate environment, to cooling down through the evaporation of body fluids and synthesizing heat shock proteins to prevent damage at the cellular level after heat exposure. In contrast, endothermy may allow an insect to fight parasitic infections, fly within a large range of Ta and facilitate nest defense. Since May (1979), Casey (1988) and Heinrich (1993) reviewed the literature on insect thermoregulation, hundreds of scientific articles have been published on the subject and new insights in several insect groups have emerged. In particular, technical advancements have provided a better understanding of the mechanisms underlying thermoregulatory processes. This present Review aims to provide an overview of these findings with a focus on various insect groups, including blood-feeding arthropods, as well as to explore the impact of thermoregulation and heat exposure on insect immunity and pathogen development. Finally, it provides insights into current knowledge gaps in the field and discusses insect thermoregulation in the context of climate change.

Exploring the antimicrobial peptidome of nematodes through phylum-spanning in silico analyses highlights novel opportunities for pathogen control.

Antimicrobial Peptides (AMPs) are key constituents of the invertebrate innate immune system and provide critical protection against microbial threat. Nematodes display diverse life strategies where they are exposed to heterogenous, microbe rich, environments highlighting their need for an innate immune system. Within the Ecdysozoa, arthropod AMPs have been well characterised, however nematode-derived AMP knowledge is limited. In this study the distribution and abundance of putative AMP-encoding genes was examined in 134 nematode genomes providing the most comprehensive profile of AMP candidates within phylum Nematoda. Through genome and transcriptome analyses we reveal that phylum Nematoda is a rich source of putative AMP diversity and demonstrate (i) putative AMP group profiles that are influenced by nematode lifestyle where free-living nematodes appear to display enriched putative AMP profiles relative to parasitic species; (ii) major differences in the putative AMP profiles between nematode clades where Clade 9/V and 10/IV species possess expanded putative AMP repertoires; (iii) AMP groups with highly restricted profiles (e.g. Cecropins and Diapausins) and others [e.g. Nemapores and Glycine Rich Secreted Peptides (GRSPs)] which are more widely distributed; (iv) complexity in the distribution and abundance of CSαß subgroup members; and (v) that putative AMPs are expressed in host-facing life stages and biofluids of key nematode parasites. These data indicate that phylum Nematoda displays diversity in putative AMPs and underscores the need for functional characterisation to reveal their role and importance to nematode biology and host-nematode-microbiome interactions.

Ultrastructure of the female pedal gonad in Phoxichilidium femoratum (Chelicerata, Pycnogonida).

Phoxichilidium femoratum is a common species of sea spiders - a small and unique group of chelicerates with unusual adult anatomy. In particular, substantial parts of the reproductive system in pycnogonids (unlike euchelicerates) are located in the appendages. Existing studies of pycnogonid gonads are often limited to light-microscopic level, cover a small range of species, and focus on the contents of the gonad diverticula. Ultrastructural data are rare and contradictory, and the organisation of the gonad wall and the gonoducts is unknown. Here we present a detailed light and transmission electron microscopy-based examination of the pedal portion of the adult female reproductive system in Phoxichilidium femoratum Rathke, 1799. We describe its gross anatomy and the ultrastructure of the gonad diverticulum, oviduct and gonopore, as well as development of the oocytes. Each gonad diverticulum is enclosed in the extracellular matrix of the horizontal septum and bears some internal cellular lining. However, neither the gonad lining, nor the septum sheath cells, ever form a continuous epithelial layer. Oocytes, which undergo maturation in the diverticulum, remain, until very late in the process, attached to the gonad wall though specialised stalk cells. Interestingly, stalk cells do not participate in egg envelope or yolk formation: both are synthesized endogenously in the oocytes. The oviduct is supplied with musculature, which assists in egg transport to the gonopore, whereas the gonopore itself is surrounded by specialised glands.

Site-specific length-biomass relationships of arctic arthropod families are critical for accurate ecological inferences.

Arthropods play a crucial role in terrestrial ecosystems, for instance in mediating energy fluxes and in forming the food base for many organisms. To better understand their functional role in such ecosystem processes, monitoring of trends in arthropod biomass is essential. Obtaining direct measurements of the body mass of individual specimens is laborious. Therefore, these data are often indirectly acquired by utilizing allometric length-biomass relationships based on a correlative parameter, such as body length. Previous studies have often used such relationships with a low taxonomic resolution and/or small sample size and/or adopted regressions calibrated in different biomes. Despite the scientific interest in the ecology of arctic arthropods, no site-specific family-level length-biomass relationships have hitherto been published. Here we present 27 family-specific length-biomass relationships from two sites in the High Arctic: Zackenberg in northeast Greenland and Knipovich in north Taimyr, Russia. We show that length-biomass regressions from different sites within the same biome did not affect estimates of phenology but did result in substantially different estimates of arthropod biomass. Estimates of daily biomass at Zackenberg were on average 24% higher when calculated using regressions for Knipovich compared to using regressions for Zackenberg. In addition, calculations of daily arthropod biomass at Zackenberg based on order-level regressions from frequently cited studies in literature revealed overestimations of arthropod biomass ranging from 69.7% to 130% compared to estimates based on regressions for Zackenberg. Our results illustrate that the use of allometric relationships from different sites can significantly alter the biological interpretation of, for instance, the interaction between insectivorous birds and their arthropod prey. We conclude that length-biomass relationships should be locally established rather than being based on global relationships.

Identification and characterization of ecdysis-related neuropeptides in the lone star tick Amblyomma americanum.

Introduction: The lone star tick, Amblyomma americanum, is an important ectoparasite known for transmitting diseases to humans and animals. Ecdysis-related neuropeptides (ERNs) control behaviors crucial for arthropods to shed exoskeletons. However, ERN identification and characterization in A. americanum remain incomplete. Methods: We investigated ERNs in A. americanum, assessing their evolutionary relationships, protein properties, and functions. Phylogeny, sequence alignment, and domain structures of ERNs were analyzed. ERN functionality was explored using enrichment analysis, and developmental and tissue-specific ERN expression profiles were examined using qPCR and RNAi experiments. Results and discussion: The study shows that ERN catalogs (i.e., eclosion hormone, corazonin, and bursicon) are found in most arachnids, and these ERNs in A. americanum have high evolutionary relatedness with other tick species. Protein modeling analysis indicates that ERNs primarily consist of secondary structures and protein stabilizing forces (i.e., hydrophobic clusters, hydrogen bond networks, and salt bridges). Gene functional analysis shows that ENRs are involved in many ecdysis-related functions, including ecdysis-triggering hormone activity, neuropeptide signaling pathway, and corazonin receptor binding. Bursicon proteins have functions in chitin binding and G protein-coupled receptor activity and strong interactions with leucine-rich repeat-containing G-protein coupled receptor 5. ERNs were expressed in higher levels in newly molted adults and synganglia. RNAi-mediated knockdown of burs α and burs ß expression led to a significant decrease in the expression of an antimicrobial peptide, defensin, suggesting they might act in signaling or regulatory pathways that control the expression of immune-related genes. Arthropods are vulnerable immediately after molting because new cuticles are soft and susceptible to injury and pathogen infections. Bursicon homodimers act in prophylactic immunity during this vulnerable period by increasing the synthesis of transcripts encoding antimicrobial peptides to protect them from microbial invasion. Collectively, the expression pattern and characterization of ERNs in this study contribute to a deeper understanding of the physiological processes in A. americanum.

Spider dynamics under vertical vibration and its implications for biological vibration sensing.

Often overlooked, vibration transmission through the entire body of an animal is an important factor in understanding vibration sensing in animals. To investigate the role of dynamic properties and vibration transmission through the body, we used a modal test and lumped parameter modelling for a spider. The modal test used laser vibrometry data on a tarantula, and revealed five modes of the spider in the frequency range of 20-200 Hz. Our developed and calibrated model took into account the bounce, pitch and roll of the spider body and bounce of all the eight legs. We then performed a parametric study using this calibrated model, varying factors such as mass, inertia, leg stiffness, damping, angle and span to study what effect they had on vibration transmission. The results support that some biomechanical parameters can act as physical constraints on vibration sensing. But also, that the spider may actively control some biomechanical parameters to change the signal intensity it can sense. Furthermore, our analysis shows that the parameter changes in front and back legs have a greater influence on whole system dynamics, so may be of particular importance for active control mechanisms to facilitate biological sensing functions.

Appendage abnormalities in spiders induced by an alternating temperature protocol in the context of recent advances in molecular spider embryology.

In the literature there are numerous reports of developmental deformities in arthropods collected in their natural habitat. Since such teratogenically affected individuals are found purely by chance, the causes of their defects are unknown. Numerous potential physical, mechanical, chemical, and biological teratogens have been considered and tested in the laboratory. Thermal shocks, frequently used in teratological research on the spider Eratigena atrica, have led to deformities on both the prosoma and the opisthosoma. In the 2020/2021 breeding season, by applying alternating temperatures (14 °C and 32 °C, changed every 12 h) for the first 10 days of embryonic development, we obtained 212 postembryos (out of 3,007) with the following anomalies: oligomely, heterosymely, bicephaly, schistomely, symely, polymely, complex anomalies, and others. From these we selected six spiders with defects on the prosoma and two with short appendages on the pedicel for further consideration. The latter cases seem particularly interesting because appendages do not normally develop on this body part, viewed as the first segment of the opisthosoma, and appear to represent examples of atavism. In view of the ongoing development of molecular techniques and recent research on developmental mechanisms in spiders, we believe the observed phenotypes may result, at least in part, from the erroneous suppression or expression of segmentation or appendage patterning genes. We consider "knockdown" experiments described in the literature as a means for generating hypotheses about the sources of temperature-induced body abnormalities in E. atrica.

Homeotic transformation in a terrestrial isopod: insights into the appendage identity in crustaceans.

In many crustacean species, an individual possesses both uniramous and biramous appendages that enable us to compare the two types on the same genetic background. Therefore, among the diverse morphologies of arthropod appendages, crustacean biramous appendages provide interesting subjects for studying the developmental mechanisms underlying appendage modifications. In this study, we report a malformed specimen of the terrestrial isopod Porcellio scaber, in which one of the pleopods was transformed into a different structure. Morphological observations of exoskeletons and musculatures by confocal scanning laser microscopy revealed that the transformed appendage was three-segmented, with at least the apical two segments having pereopod-like musculoskeletal structures. The apical segment of the transformed appendage lacked muscles, and the following segment had a pair of muscle bundles. These findings together with those of some previous studies of gene expression patterns in this species suggest that this anomaly could be caused by homeotic transformation of a flap-like pleopod into a three-segmented pereopod tip, which may be a homologous structure of the pleopod.

Methods for the Study of Ticks, Mosquitoes, and their Transmitted Pathogens: Toward a Greater Understanding of Vector Biology and Arthropod-Microbe Interactions.

ARTICLES DISCUSSED: Chen, L., Xiao, Q., Shi, M., Cheng, J., Wu, J. Detecting Wolbachia strain wAlbB in Aedes albopictus cell lines. Journal of Visualized Experiments. (184), e63662 (2022). Haziqah-Rashid, A. et al. Determining temperature preference of mosquitoes and other ectotherms. Journal of Visualized Experiments. (187), e64356 (2022). Huang, D. et al. Mosquito-associated virus isolation from field-collected mosquitoes. Journal of Visualized Experiments. (186), e63852 (2022). Khoo, B., Cull, B., Oliver, J. D. Tick artificial membrane feeding for Ixodes scapularis. Journal of Visualized Experiments. 64553 (2022). Leal-Galvan, B., Harvey, C., Thomas, D., Saelao, P., Oliva Chavez, A. S. Isolation of microRNAs from tick ex vivo salivary gland cultures and extracellular vesicles. Journal of Visualized Experiments. (182), e63618 (2022). Liang, Q. et al. Control of Aedes albopictus mosquito larvae with Carpesium abrotanoides L. Journal of Visualized Experiments. (186), e63976 (2022). Wang, F. et al. Experimental viral infection in adult mosquitoes by oral feeding and microinjection. Journal of Visualized Experiments. (185), e63830 (2022). Wang, X. R., Burkhardt, N. Y., Price, L. D., Munderloh, U. G. An electroporation method to transform Rickettsia spp. with a fluorescent protein-expressing shuttle vector in tick cell lines. Journal of Visualized Experiments. (188), e64562 (2022).

Optogenetic cleavage of the Miro GTPase reveals the direct consequences of real-time loss of function in Drosophila.

Miro GTPases control mitochondrial morphology, calcium homeostasis, and regulate mitochondrial distribution by mediating their attachment to the kinesin and dynein motor complex. It is not clear, however, how Miro proteins spatially and temporally integrate their function as acute disruption of protein function has not been performed. To address this issue, we have developed an optogenetic loss of function "Split-Miro" allele for precise control of Miro-dependent mitochondrial functions in Drosophila. Rapid optogenetic cleavage of Split-Miro leads to a striking rearrangement of the mitochondrial network, which is mediated by mitochondrial interaction with the microtubules. Unexpectedly, this treatment did not impact the ability of mitochondria to buffer calcium or their association with the endoplasmic reticulum. While Split-Miro overexpression is sufficient to augment mitochondrial motility, sustained photocleavage shows that Split-Miro is surprisingly dispensable to maintain elevated mitochondrial processivity. In adult fly neurons in vivo, Split-Miro photocleavage affects both mitochondrial trafficking and neuronal activity. Furthermore, functional replacement of endogenous Miro with Split-Miro identifies its essential role in the regulation of locomotor activity in adult flies, demonstrating the feasibility of tuning animal behaviour by real-time loss of protein function.

Alkaline water as a potential agent for biting midge control: Managing effectiveness and non-target organism impact evaluation.

Biting midge Forcipomyia taiwana is one of the common pests in East Asia. Their nuisance and blood-sucking behavior causes problems not only for human health but also for some industries. This study aims to evaluate the effectiveness of spraying alkaline water on controlling biting midge population and potential side effects of such approach on non-target organisms. Laboratory experiments were conducted to evaluate the effect of alkaline water on oviposition site preference of female biting midges as well as crickets. Effect of alkaline water on distribution pattern of earthworms was also examined. Besides, we also performed field manipulative studies by long term spraying of alkaline water to evaluate the effects on biting midge density, microalgae abundance and ground arthropod communities. The results of laboratory experiments showed that female biting midges laid significantly fewer eggs in surface treated with alkaline water. However, alkaline water treatment did not significantly affect the oviposition site choice of crickets and distribution pattern of earthworms. Result of field manipulations showed that long-term spraying of alkaline water could significantly reduce the abundance of soil microalgae and density of biting midges, but did not affect the diversity of non-target ground arthropods. These results demonstrate that long-term spraying of alkaline water could decrease biting midge density without harming co-existing non-target organisms and therefore is a potentially eco-friendly approach to control such pest.

Invasive hematophagous arthropods and associated diseases in a changing world.

Biological invasions have increased significantly with the tremendous growth of international trade and transport. Hematophagous arthropods can be vectors of infectious and potentially lethal pathogens and parasites, thus constituting a growing threat to humans-especially when associated with biological invasions. Today, several major vector-borne diseases, currently described as emerging or re-emerging, are expanding in a world dominated by climate change, land-use change and intensive transportation of humans and goods. In this review, we retrace the historical trajectory of these invasions to better understand their ecological, physiological and genetic drivers and their impacts on ecosystems and human health. We also discuss arthropod management strategies to mitigate future risks by harnessing ecology, public health, economics and social-ethnological considerations. Trade and transport of goods and materials, including vertebrate introductions and worn tires, have historically been important introduction pathways for the most prominent invasive hematophagous arthropods, but sources and pathways are likely to diversify with future globalization. Burgeoning urbanization, climate change and the urban heat island effect are likely to interact to favor invasive hematophagous arthropods and the diseases they can vector. To mitigate future invasions of hematophagous arthropods and novel disease outbreaks, stronger preventative monitoring and transboundary surveillance measures are urgently required. Proactive approaches, such as the use of monitoring and increased engagement in citizen science, would reduce epidemiological and ecological risks and could save millions of lives and billions of dollars spent on arthropod control and disease management. Last, our capacities to manage invasive hematophagous arthropods in a sustainable way for worldwide ecosystems can be improved by promoting interactions among experts of the health sector, stakeholders in environmental issues and policymakers (e.g. the One Health approach) while considering wider social perceptions.