Urban living can rescue Darwin's finches from the lethal effects of invasive vampire flies.

Human activity changes multiple factors in the environment, which can have positive or negative synergistic effects on organisms. However, few studies have explored the causal effects of multiple anthropogenic factors, such as urbanization and invasive species, on animals and the mechanisms that mediate these interactions. This study examines the influence of urbanization on the detrimental effect of invasive avian vampire flies (Philornis downsi) on endemic Darwin's finches in the Galápagos Islands. We experimentally manipulated nest fly abundance in urban and non-urban locations and then characterized nestling health, fledging success, diet, and gene expression patterns related to host defense. Fledging success of non-parasitized nestlings from urban (79%) and non-urban (75%) nests did not differ significantly. However, parasitized, non-urban nestlings lost more blood, and fewer nestlings survived (8%) compared to urban nestlings (50%). Stable isotopic values (δ15 N) from urban nestling feces were higher than those from non-urban nestlings, suggesting that urban nestlings are consuming more protein. δ15 N values correlated negatively with parasite abundance, which suggests that diet might influence host defenses (e.g., tolerance and resistance). Parasitized, urban nestlings differentially expressed genes within pathways associated with red blood cell production (tolerance) and pro-inflammatory response (innate immunological resistance), compared to parasitized, non-urban nestlings. In contrast, parasitized non-urban nestlings differentially expressed genes within pathways associated with immunoglobulin production (adaptive immunological resistance). Our results suggest that urban nestlings are investing more in pro-inflammatory responses to resist parasites but also recovering more blood cells to tolerate blood loss. Although non-urban nestlings are mounting an adaptive immune response, it is likely a last effort by the immune system rather than an effective defense against avian vampire flies since few nestlings survived.

Unveiling the hidden dangers: enteropathogens carried by flies in Pudong New Area.

BACKGROUND: Flies are acknowledged as vectors of diseases transmitted through mechanical means and represent a significant risk to human health. The study aimed to determine the prevalence of enteropathogens carried by flies in Pudong New Area to inform strategies for preventing and controlling flies. METHODS: Samples were collected from various locations in the area using cage trapping techniques between April and November 2021, encompassing various habitats such as parks, residential areas, restaurants, and farmers' markets. The main fly species were identified using cryomicrography and taxonomic enumeration, with 20 samples per tube collected from different habitats. Twenty-five enteropathogens were screened using GI_Trial v3 TaqManTM microbial arrays. RESULTS: A total of 3,875 flies were collected from 6,400 placements, resulting in an average fly density of 0.61 flies per cage. M. domestica were the most common species at 39.85%, followed by L. sericata at 16.57% and B. peregrina at 13.14%. Out of 189 samples, 93 tested positive for enteropathogens, with nine different pathogens being found. 12.70% of samples exclusively had parasites, a higher percentage than those with only bacteria or viruses. The study found that M. domestica had fewer enteropathogens than L. sericata and B. peregrina, which primarily harbored B. hominis instead of bacteria and viruses such as E. coli, Astrovirus, and Sapovirus. During spring testing, all three fly species exhibited low rates of detecting enteropathogens. M. domestica were found in residential areas with the highest number of pathogen species, totaling six. In contrast, L. sericata and B. peregrina were identified in farmers' markets with the highest number of pathogen species, totaling six and seven, respectively. CONCLUSIONS: Flies have the potential to serve as vectors for the transmission of enteropathogens, thereby posing a substantial risk to public health.

Evaluation of mechanical transmission of Trypanosoma vivax by Stomoxys calcitrans in a region without a cyclic vector.

This work investigated the mechanical transmission of Trypanosoma vivax by Stomoxys calcitrans to cattle in a region without a cyclic vector. The study involved two experiments, one with calves experimentally infected with T. vivax, in the acute phase of trypanosomosis (Experiment 1) and the other in the chronic phase (Experiment 2). In both experiments, two transmission methods were used with flies that had not fed for 24 h or had never fed: (i) Method 1: flies released freely in cattle pens (≈3,300 flies/pen for 10 days); and (ii) Method 2: flies placed in a feeding chamber (12 flies/animal). To develop Method 1 in the two experiments (acute and chronic phases), T. vivax-positive animals were kept with T. vivax-negative animals. Periodically, the Brener method, Woo method, blood smears, cPCR, ELISA, IFAT, and Imunoteste® were performed to detect T. vivax in the animals. We also recorded the animals' head tossing and hoof stomping and the number of flies near the pens' inner walls. Subsequently, biological testing was performed using lambs. For Method 2 in both experiments, flies inside the feeding chamber first fed on T. vivax-positive animals and later on negative animals. In both experiments and methods, we examined the flies for the presence of T. vivax through blood smears and cPCR of the proboscis and abdomen. In Experiment 2 (chronic phase), a test was conducted to determine how long trypomastigotes forms could survive on the blood of animals with different levels of parasitemia. None of the animals (calves and lambs) became infected with T. vivax or showed antibodies against it. During the evaluation period, the animals in the presence of the flies exhibited more hoof stomping and head tossing compared to those without flies (control). Additionally, there was an increase in the number of flies in the pens during the experiment. Only in Experiment 1 (acute phase) were T. vivax trypomastigotes and DNA found in the abdomen of the flies but not in the proboscis. In Experiment 2 (chronic phase), higher concentrations of trypomastigotes per milliliter of blood were associated with a shorter the lifespan of this stage of the parasite. In conclusion, under the variable conditions of the experiments (hosts, number of flies, and level of parasitemia), S. calcitrans was unable to mechanically transmit T. vivax to cattle.

Molecular detection and genotyping of Dientamoeba fragilis and Blastocystis sp. in housefly Musca domestica (Diptera: Muscidae): first report for Dientamoeba fragilis.

Dientamoeba fragilis and Blastocystis sp. are single-celled protozoan parasites of humans and animals. Although they are found in the intestines of healthy hosts, the pathogenicity of them is still unclear. To date, there is no report on D. fragilis and only two studies (without subtyping) on the occurrence of Blastocystis sp. in Musca domestica. In this study, fly samples were collected from livestock farms and their surroundings in the Kirsehir province (Central Anatolia Region) of Türkiye from May to August 2023. A total of 150 microscopically identified M. domestica samples were analyzed for the detection of D. fragilis and Blastocystis sp. molecularly. The overall prevalence of Blastocystis sp. and D. fragilis in M. domestica was determined to be 3.3% (5/150) and 8.0% (12/150), respectively. The SSU rRNA gene sequences of the isolates indicated genotype 1 of D. fragilis. Eleven isolates were identical and represented a single isolate (KAU-Dfrag1). BLAST analysis of KAU-Dfrag1 indicated identity with the isolates reported from humans, cattle, sheep, and budgerigars. The other isolate (KAU-Dfrag2) was polymorphic at two nucleotides from KAU-Dfrag1 and three nucleotides from known genotypes from GenBank and represented a variant of genotype 1. The Blastocystis sp. isolates were found to be identical and represent a single genotype (KAU-Blast1). BLAST analysis revealed that the KAU-Blast1 genotype belonged to the potentially zoonotic subtype 5 (ST5) and exhibited the highest genetic identity (ranging from 99.4 to 99.6%) with pigs, cattle, and sheep from different countries. Our study provides the first data on the molecular prevalence, epidemiology, and genotypic characterization of D. fragilis and Blastocystis sp. in M. domestica.

Black blow fly (Diptera: Calliphoridae) bacterial symbionts inform oviposition site selection by stable flies (Diptera: Muscidae).

Larval habitats of blood-feeding stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), overlap with foraging sites of black blow flies, Phormia regina (Meigen) (Diptera: Calliphoridae). We tested the hypothesis that bacteria in blow fly excreta inform oviposition decisions by female stable flies. In laboratory 2-choice bioassays, we offered gravid female stable flies fabric-covered agar plates as oviposition sites that were kept sterile or inoculated with either a blend of 7 bacterial strains isolated from blow fly excreta (7-isolate-blend) or individual bacterial isolates from that blend. The 7-isolate-blend deterred oviposition by female stable flies, as did either of 2 strains of Morganella morganii subsp. sibonii. Conversely, Exiguobacterium sp. and Serratia marcescens each prompted oviposition by flies. The flies' oviposition decisions appear to be guided by bacteria-derived semiochemicals as the bacteria could not be physically accessed. Oviposition deterrence caused by semiochemicals of the 7-isolate-blend may help stable flies avoid competition with blow flies. The semiochemicals of bioactive bacterial strains could be developed as trap lures to attract and capture flies and deter their oviposition in select larval habitats.

The Acquisition and Retention of Lumpy Skin Disease Virus by Blood-Feeding Insects Is Influenced by the Source of Virus, the Insect Body Part, and the Time since Feeding.

Lumpy skin disease virus (LSDV) is a poxvirus that causes severe systemic disease in cattle and is spread by mechanical arthropod-borne transmission. This study quantified the acquisition and retention of LSDV by four species of Diptera (Stomoxys calcitrans, Aedes aegypti, Culex quinquefasciatus, and Culicoides nubeculosus) from cutaneous lesions, normal skin, and blood from a clinically affected animal. The acquisition and retention of LSDV by Ae. aegypti from an artificial membrane feeding system was also examined. Mathematical models of the data were generated to identify the parameters which influence insect acquisition and retention of LSDV. For all four insect species, the probability of acquiring LSDV was substantially greater when feeding on a lesion compared with feeding on normal skin or blood from a clinically affected animal. After feeding on a skin lesion LSDV was retained on the proboscis for a similar length of time (around 9 days) for all four species and for a shorter time in the rest of the body, ranging from 2.2 to 6.4 days. Acquisition and retention of LSDV by Ae. aegypti after feeding on an artificial membrane feeding system that contained a high titer of LSDV was comparable to feeding on a skin lesion on a clinically affected animal, supporting the use of this laboratory model as a replacement for some animal studies. This work reveals that the cutaneous lesions of LSD provide the high-titer source required for acquisition of the virus by insects, thereby enabling the mechanical vector-borne transmission. IMPORTANCE Lumpy skin disease virus (LSDV) is a high consequence pathogen of cattle that is rapidly expanding its geographical boundaries into new regions such as Europe and Asia. This expansion is promoted by the mechanical transmission of the virus via hematogenous arthropods. This study quantifies the acquisition and retention of LSDV by four species of blood-feeding insects and reveals that the cutaneous lesions of LSD provide the high titer virus source necessary for virus acquisition by the insects. An artificial membrane feeding system containing a high titer of LSDV was shown to be comparable to a skin lesion on a clinically affected animal when used as a virus source. This promotes the use of these laboratory-based systems as replacements for some animal studies. Overall, this work advances our understanding of the mechanical vector-borne transmission of LSDV and provides evidence to support the design of more effective disease control programmes.

Effect of urbanization and parasitism on the gut microbiota of Darwin's finch nestlings.

Host-associated microbiota can be affected by factors related to environmental change, such as urbanization and invasive species. For example, urban areas often affect food availability for animals, which can change their gut microbiota. Invasive parasites can also influence microbiota through competition or indirectly through a change in the host immune response. These interacting factors can have complex effects on host fitness, but few studies have disentangled the relationship between urbanization and parasitism on an organism's gut microbiota. To address this gap in knowledge, we investigated the effects of urbanization and parasitism by the invasive avian vampire fly (Philornis downsi) on the gut microbiota of nestling small ground finches (Geospiza fuliginosa) on San Cristóbal Island, Galápagos. We conducted a factorial study in which we experimentally manipulated parasite presence in an urban and nonurban area. Faeces were then collected from nestlings to characterize the gut microbiota (i.e. bacterial diversity and community composition). Although we did not find an interactive effect of urbanization and parasitism on the microbiota, we did find main effects of each variable. We found that urban nestlings had lower bacterial diversity and different relative abundances of taxa compared to nonurban nestlings, which could be mediated by introduction of the microbiota of the food items or changes in host physiology. Additionally, parasitized nestlings had lower bacterial richness than nonparasitized nestlings, which could be mediated by a change in the immune system. Overall, this study advances our understanding of the complex effects of anthropogenic stressors on the gut microbiota of birds.

Molecular evidence of Anaplasma spp. in blood-sucking flies from China and identification of a putative novel Anaplasma species.

Tabanids and stomoxes are important mechanical vectors for the transmission of pathogens. Although the agents they transmitted have been well studied, bacteria of the genus Anaplasma harbored by these flies have never been reported in China. In this study, 262 blood-sucking flies (128 Stomoxys calcitrans, 45 Tabanus birmanicus, 69 Tabanus hypomacros, and 20 Tabanus taiwanus) were collected from the Wuhan and Nanping cities of China. Anaplasma marginale, Anaplasma bovis, and Candidatus Anaplasma cinensis are detected in S. calcitrans from Wuhan City, with positive rates of 15.63%, 1.56%, and 7.81%, respectively. Out of our expectations, a putative novel Anaplasma species was identified in all three tabanid species (40.00% in T. birmanicus, 15.94% in T. hypomacros, and 10.00% in T. taiwanus) from Nanping City. The 16 S rRNA and groEL gene sequences have highest 99.37-99.75% and 91.46% identities to A. marginale, while the gltA gene sequences have highest 88.34% identity to Anaplasma centrale. In the phylogenetic trees, these strains form a distinct clade. Herein we name it "Candidatus Anaplasma nanpingensis". The present study shows the existence of multiple Anaplasma species in blood-sucking flies in China. This may be the first report that blood-sucking flies harbor Anaplasma in China.

Stable flies sense and behaviorally respond to the polarization of light.

Insects use their polarization-sensitive photoreceptors in a variety of ecological contexts including host-foraging. Here, we investigated the effect of polarized light on host foraging by the blood-feeding stable fly, Stomoxys calcitrans, a pest of livestock. Electroretinogram recordings with chromatic adaptation demonstrated that the spectral sensitivity of stable flies resembles that of other calyptrate flies. Histological studies of the flies' compound eye revealed differences in microvillar arrangement of ommatidial types, assumed to be pale and yellow, with the yellow R7 and pale R8 photoreceptors having the greatest polarization sensitivity. In behavioural experiments, stable flies preferred to alight on horizontally polarized stimuli with a high degree of linear polarization. This preferential response disappeared when either ultraviolet (UV) or human-visible wavelengths were omitted from light stimuli. Removing specific wavelength bands further revealed that the combination of UV (330-400 nm) and blue (400-525 nm) wavelength bands was sufficient to enable polarized light discrimination by flies. These findings enhance our understanding of polarization vision and foraging behavior among hematophagous insects and should inform future trap designs.

Global population genetic structure and lineage differentiation of the stable fly, Stomoxys calcitrans.

The bloodsucking fly, Stomoxys calcitrans (Diptera: Muscidae), is a cosmopolitan pest that transmits potential pathogens mechanically. We conduct phylogeographic analyses of S. calcitrans to resolve its global population genetic structure for establishing baseline of molecular studies. Results from mitochondrial gene suggested that the major divergence of S. calcitrans predominantly occurred 0.32-0.47 million years ago (Mya) and the subsequent diversifications took place during 0.13-0.27 Mya. The Ethiopian region was deduced as the most likely origin of S. calcitrans and the Nearctic lineages were considered to have originated from Oriental or Palaearctic regions. Our results further revealed that each biogeographic region of S. calcitrans likely maintains its genetic specialty, and yet, those non-monophyletic relationships were possibly caused by ancestral retention, dispersal with mammals, long-distance migration, and the international livestock industries. Moreover, the three highly diverged Ethiopian lineages may be putative cryptic species that require clarification of their veterinary importance. Unravelling the genetic structure of stable fly and preventing gene flow among biogeographic regions through anthropogenic activities are thus pivotal in livestock industry administration, particularly genetic exchange among differentiated lineages that might lead to the consequence of ecological trait alterations.

Machine learning analysis of wing venation patterns accurately identifies Sarcophagidae, Calliphoridae and Muscidae fly species.

In medical, veterinary and forensic entomology, the ease and affordability of image data acquisition have resulted in whole-image analysis becoming an invaluable approach for species identification. Krawtchouk moment invariants are a classical mathematical transformation that can extract local features from an image, thus allowing subtle species-specific biological variations to be accentuated for subsequent analyses. We extracted Krawtchouk moment invariant features from binarised wing images of 759 male fly specimens from the Calliphoridae, Sarcophagidae and Muscidae families (13 species and a species variant). Subsequently, we trained the Generalized, Unbiased, Interaction Detection and Estimation random forests classifier using linear discriminants derived from these features and inferred the species identity of specimens from the test samples. Fivefold cross-validation results show a 98.56 ± 0.38% (standard error) mean identification accuracy at the family level and a 91.04 ± 1.33% mean identification accuracy at the species level. The mean F1-score of 0.89 ± 0.02 reflects good balance of precision and recall properties of the model. The present study consolidates findings from previous small pilot studies of the usefulness of wing venation patterns for inferring species identities. Thus, the stage is set for the development of a mature data analytic ecosystem for routine computer image-based identification of fly species that are of medical, veterinary and forensic importance.

Larval morphology of the avian parasitic genus Passeromyia: playing hide and seek with a parastomal bar.

The enigmatic larvae of the Old World genus Passeromyia Rodhain & Villeneuve, 1915 (Diptera: Muscidae) inhabit the nests of birds as saprophages or as haematophagous agents of myiasis among nestlings. Using light microscopy, confocal laser scanning microscopy and scanning electron microscopy, we provide the first morphological descriptions of the first, second and third instar of P. longicornis (Macquart, 1851) (Diptera: Muscidae), the first and third instar of P. indecora (Walker, 1858) (Diptera: Muscidae), and we revise the larval morphology of P. heterochaeta (Villenueve, 1915) (Diptera: Muscidae) and P. steini Pont, 1970 (Diptera: Muscidae). We provide a key to the third instar of examined species (excluding P. steini and P. veitchi Bezzi, 1928 (Diptera: Muscidae)). Examination of the cephaloskeleton revealed paired rod-like sclerites, named 'rami', between the lateral arms of the intermediate sclerite in the second and third instar larva. We reveal parastomal bars fused apically with the intermediate sclerite, the absence of which has so far been considered as apomorphic for second and third instar muscid larvae. Examination of additional material suggests that modified parastomal bars are not exclusive features of Passeromyia but occur widespread in the Muscidae, and rami may occur widespread in the Cyclorrhapha.

Pasture dragging fails to reliably suppress the emergence of horn flies (Haematobia irritans) and face flies (Musca autumnalis) from dung pats in a Mid-Atlantic North American climate.

The beef industry endures major economic losses from a complex of flies that feed on bovine blood and mucus. For cattle on pasture, the most important of these pests are horn flies (Haematobia irritans [L.] [Diptera: Muscidae]) and face flies (Musca autumnalis [Diptera: Muscidae] De Geer). Pasture dragging to spread manure pats has been promoted as a management tactic for these species because their larvae inhabit bovine manure pats, but the efficacy of this practice has not been empirically validated. Spreading pats might promote fly mortality through desiccation or overheating, but these processes are weather-dependent and warrant testing in disparate climates. We evaluated pasture dragging effects while monitoring for weather interactions throughout nine experiment rounds in summers of 2018 and 2020 in Pennsylvania, USA. The manure spreading treatments increased pat surface area up to 300% but failed to significantly reduce emergence of horn flies and face flies as compared to controls. In contrast, precipitation and temperature were significant predictors in fly emergence models. Surprisingly, face fly emergence was significantly elevated in dragged pats twice in 2020. These data call for a reevaluation of pasture dragging as a management technique for horn flies and face flies across a range of climates.

Imidacloprid-induced mortality, histopathology and biochemical impairments in the larvae of oriental latrine fly (Chrysomya megacephala).

The concentration-mortality response of third instar larvae of Chrysomya megacephala (Diptera: Calliphoridae) to a synthetic insecticide, imidacloprid, and its impact on histopathological, histochemical, and biochemical parameters were determined in laboratory assays. Larvae displayed a concentration and time-dependent mortality response for the insecticide. Histopathological studies exhibited quite noticeable modifications in the epithelial cells, peritrophic membrane, basement membrane and muscular layer of the larval midgut. The ultrastructural analysis demonstrated alterations in nuclei, lipid spheres, microvilli, mitochondria, rough endoplasmic reticulum and lysosomes. In addition, histochemical tests on the midgut were performed, which revealed a strong reaction for proteins and carbohydrates in the control group and a weak reaction in the group exposed to imidacloprid in a dose and time-dependent manner. Imidacloprid also caused a significant reduction in the total midgut content of carbohydrates, proteins, lipids and cholesterol. Larvae treated with imidacloprid also showed a reduction in the activities of acid and alkaline phosphatases at all concentrations compared to untreated larvae.

Presence of the toxigenic fungi Aspergillus spp. and Fusarium spp. in Musca domestica L. (Diptera: Muscidae) collected from dairy farms.

The objective of the study was to identify the presence of toxigenic fungi Aspergillus spp. and Fusarium spp. in domestic flies collected from dairy farms. We selected 10 dairy farms distributed in the central valley of the state of Aguascalientes, México. The flies were trapped using entomological traps with an olfactory attractant in 7 sites of the farm (silo-cutting surface, feed store, milking parlor, 3 feeders, and the rearing room). The fungi were cultivated in Sabouraud agar through direct sowing by serial dilutions to obtain the isolates, and a taxonomical identification was carried out under the microscope. The aflatoxins and zearalenone production capacity of the pure isolates were quantified using the ELISA test. The flies were present in all of the capture sites (45.3 flies, 567 mg, trap per day). We obtained 50 isolates of Aspergillus spp. genus, 12 of which produced aflatoxins (327 ± 143 µg/kg), whereas from 56 of the Fusarium spp. isolates, 10 produced large quantities of zearalenone (3,132 ± 665 µg/kg). These results suggest that the presence of domestic flies on dairy farms can constitute a source of dissemination for toxigenic fungi that can eventually contaminate grains and forage that are part of the daily cattle diet.

Seasonal variation in tsetse fly apparent density and Trypanosoma spp. infection rate and occurrence of drug-resistant trypanosomes in Lambwe, Kenya.

Tsetse flies are major arthropod vectors of trypanosomes that cause debilitating African animal trypanosomiasis. The emergence of drug-resistant trypanosomes is a common problem in sub-Saharan Africa. This study aimed to identify tsetse flies' seasonal variation in apparent densities and their infection rates and the occurrence of drug-resistant trypanosomes. Tsetse flies were collected from Lambwe, Kenya, during May and September 2021. Genomic DNA was extracted from them, and the ITS1 gene was amplified to detect Trypanosoma infection with subsequent species determination. Transporter genes DMT, E6M6, TbAT/P2, and TcoAde2 were targeted to detect polymorphisms associated with drug-resistance, using sequencing and comparison to drug-sensitive trypanosome species referenced in Genbank. A total of 498 tsetse flies and 29 non-tsetse flies were collected. The apparent density of flies was higher in wet season 6.2 fly per trap per density (FTD) than in the dry season 2.3 FTD (P = 0.001), with n = 386 and n = 141 flies caught in each season, respectively. Male tsetse flies (n = 311) were more numerous than females (n = 187) (P = 0.001). Non-tsetse flies included Tabanids and Stomoxys spp. Overall, Trypanosoma infection rate in tsetse was 5% (25/498) whereby Trypanosoma vivax was 4% (11/25), Trypanosoma congolense 36% (9/25), and Trypanosoma brucei 20% (5/25) (P = 0.186 for the distribution of the species), with infections being higher in females (P = 0.019) and during the wet season (P < 0.001). Numerous polymorphisms and insertions associated with drug resistance were detected in DMT and E6M6 genes in two T. congolense isolates while some isolates lacked these genes. T. brucei lacked TbAT/P2 genes. TcoAde2 sequences in three T. congolense isolates were related to those observed in trypanosomes from cattle blood in our previous study, supporting tsetse fly involvement in transmission in the region. We report Trypanosoma associated with trypanocidal drug-resistance in tsetse flies from Lambwe, Kenya. Female tsetse flies harbored more Trypanosoma infections than males. Tsetse transmission of trypanosomes is common in Lambwe. Risk of trypanosome infection would seem higher in the wet season, when tsetse flies and Trypanosoma infections are more prevalent than during the dry season. More efforts to control animal trypanosome vectors in the region are needed, with particular focus on wet seasons.

Efficacy of topical administration of prallethrin-permethrin-piperonyl butoxide (Bronco® Equine Fly Spray) for the treatment and control of flies and other nuisance insects of horses.

Numerous biting and nuisance insects are a noted cause of discomfort and stress to horses. Pyrethrins and pyrethroids have been used for many years in numerous formulations for the control of insect pests in animals, humans and environment. There are, however, few studies reporting their field efficacy in horses. The aim of the present study was to evaluate the repellent activity of a spray formulation based on prallethrin and permethrin synergized with piperonyl butoxide (BRONCO® Equine Fly Spray, Farnam Companies, Inc., USA) against annoying and harmful insects for horses in field conditions. Nine horses of mixed breed were divided into 2 groups (treatment and control). Pre-treatment insect counts were compared to daily counts for 4 days post-treatment (pt). One minute after the administration of the product (day 0), all the horses were negative for the presence of insects. All counts up to the 6-h pt check remained negative for Hippobosca equina, tabanid flies and Simulium spp., showing 100% efficacy. This remained above 90% throughout the study. For the H. equina, the repellent efficacy remained > 99.7% for all 4 days pt, for tabanid flies > 93.3% and for Simulium spp. > 97.4%. The efficacy against Musca spp. decreased from 82.2% at day 0 to 62.2% at day 3. Treatment was well-tolerated. In conclusion, despite the low number of tested horses, Bronco® has demonstrated high insecticide and repellent efficacy and a good persistence, maintained for up to 4 days post-treatment, against the most common species of insects harmful for horses.

Molecular analysis of acetylcholinesterase gene in field-collected populations of Musca domestica (Diptera: Muscidae) in Northwestern Iran.

Nowadays, pyrethroid (Py) insecticides are commonly used against household insect pests and housefly. The combination of Py and organophosphates (OP) are also utilized to combat these insects. The resistance status of Iranian housefly populations to them and carbamate (CB) insecticides is uncertain. This study investigates the presence of acetylcholinesterase (AChE) mutations related to the resistance of Musca domestica to OP and/or CB insecticides in Northwestern Iran. Nucleotides 1041-1776, based on their positions in the ACE gene of aabys strain, were amplified and sequenced in houseflies collected from West Azerbaijan, Gilan, and Ardebil Provinces, Iran. Among 12 single-nucleotide polymorphisms detected, 3 mismatches were found at nucleotides 1174 (T/A, G), 1473 (G/T, C), and 1668 (T/A), leading to amino acid substitutions in V260L, G342A/V, and F407Y positions with various combinations. Genotyping results showed that 85% of specimens had at least one of these substitutions. In addition, the Iranian housefly population was composed of 5 insensitive and sensitive alleles. For the first time, the current study reports the presence of V260L, G342A, G342V, and F407Y substitutions in M. domestica specimens collected from Northwestern Iran. The selection of multiple alleles in field populations might be due to the application of various pesticides/insecticides during extended periods in the region. These molecular levels signify the presence of control problems in the area and the need for developing effective control strategies for such populations.

Insecticidal and Synergistic Potential of Three Monoterpenoids against the Yellow Fever Mosquito, Aedes aegypti (Diptera: Culicidae), and the House Fly, Musca domestica (Diptera: Muscidae).

As resistance to the limited number of insecticides available for medical and veterinary pests becomes more widespread, there is an urgent need for new insecticides and synergists on the market. To address this need, we conducted a study to assess the toxicity of three monoterpenoids-carvone, menthone, and fenchone-in comparison to permethrin and methomyl against adults of two common pests: the yellow fever mosquito (Aedes aegypti) and the house fly (Musca domestica). We also examined the potential for these monoterpenoids to enhance the effectiveness of permethrin and methomyl when used together. Finally, we evaluated the ability of each monoterpenoid to inhibit acetylcholinesterase, comparing them to methomyl. While all three monoterpenoids performed relatively poorly as topical insecticides (LD50 > 4000 ng/mg on M. domestica; >6000 ng/mg on Ae. aegypti), they synergized both permethrin and methomyl as well as or better than piperonyl butoxide (PBO). Carvone and menthone yielded synergistic co-toxicity factors (23 and 29, respectively), which were each higher than PBO at 24 h. Currently, the mechanism of action is unknown. During preliminary testing, symptoms of acetylcholinesterase inhibition were identified, prompting further testing. Acetylcholinesterase inhibition did not appear to explain the toxic or synergistic effects of the three monoterpenoids, with IC50 values greater than 1 mM for all, compared to the 2.5 and 1.7 µM for methomyl on Aedes aegypti and Musca domestica, respectively. This study provides valuable monoterpenoid toxicity and synergism data on two pestiferous insects and highlights the potential for these chemistries in future pest control formulations.

Effects of habitat and sampling time on bacterial community composition and diversity in the gut of the female house fly, Musca domestica Linnaeus (Diptera: Muscidae).

Adult house flies feed and breed in a variety of microbe-rich habitats and serve as vectors for human and animal pathogens. To better understand their role in harbouring and disseminating bacteria, we characterized the composition and diversity of bacterial communities in the gut of female house flies collected from three different habitats in Kansas: agricultural (dairy farm), urban (business area dumpsters) and mixed (business located between residential and animal agriculture areas). Bacterial community composition and diversity were influenced more by the house flies' habitat than by sampling time. The most abundant taxa were also highly prevalent in the house flies collected from all three habitats, potentially representing a 'core microbiome' attributable to the fly's trophic and reproductive associations with substrates and food sources comprised of decaying matter and/or animal waste. Bacterial taxa associated with vertebrate guts/faeces and potential pathogens were highly abundant in agricultural fly microbial communities. Interestingly, taxa of potential pathogens were highly abundant in flies from the mixed and urban sites. House flies harboured diverse bacterial communities influenced by the habitat in which they reside, including potential human and animal pathogens, further bolstering their role in the dissemination of pathogens, and indicating their utility for pathogen surveillance.