Medical and Veterinary Entomology

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/700930v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@177a6b4org.highwire.dtl.DTLVardef@6186a3org.highwire.dtl.DTLVardef@ce6196org.highwire.dtl.DTLVardef@168bf43_HPS_FORMAT_FIGEXP M_FIG C_FIG The kangaroo soft tick, Australpavlovskyella gurneyi (Warburton, 1926), is found in sandy depressions ( wallows), under desert shade trees, formed by the activity of the red kangaroo, Osphranter rufus, resting under shade trees (https://youtu.be/AYLoqqPsifc). The field biology of the tick was examined on Moralana Station in arid mid-north, South Australia, between February 1969 and March 1971. The age of kangaroo dung in wallows showed that kangaroos visited wallows regularly during the hot summer and infrequently during the cooler months. All nymphal instars and adults were present at all times of the year in kangaroo wallows, but only a small proportion of the ticks present was trapped on any one occasion. Ticks were abundant in large kangaroo wallows under trees with dense shade, but scarce under smaller trees with sparse shade. The short-lived larvae were present only during spring and early summer, indicating that the long-lived female ticks bred only during spring and early summer. Laboratory tests showed that field-collected adult female ticks entered reproductive diapause from January to August (mid-summer to late-winter). Ticks placed in kangaroo wallows survived for at least one year without food. On Moralana Station, the population of first-instar nymphs increased in summer and subsequently the population of second-instar nymphs increased in early autumn, indicating that a life cycle could be completed in 2-3 years. HighlightsO_LIThe seasonal biology of Australpavlovskyella gurneyi, found in sandy depressions wallows formed by the activity of the red kangaroo, under sparse semi-arid desert shade trees was examined for the first time. C_LIO_LIEngorged ticks placed in kangaroo wallows survived for at least one year without food. C_LIO_LIIn this environment, the entire life cycle could be completed in 2-3 years. C_LI

BackgroundTemperature choice is a vector trait that influences microhabitat selection and can have important implications for vector species, as it may affect how often vectors encounter hosts. Aedes aegypti and Ae. albopictus are disease vectors whose geographic ranges continue to expand each year. One aspect that remains largely understudied is the altitudinal range of these species and the extent of differences in thermal behavior between lowland and highland populations. MethodsI collected Ae. aegypti and Ae. albopictus on the islands of Bioko and Sao Tome. I compared the distribution of the two species along an altitudinal cline spanning 2,000 m of elevation. I then used live specimens to test temperature preference for both species in a laboratory thermocline. ResultsI report the distribution of these two species on the island of Bioko and show that the abundance of immature stages of both species follows a negative exponential decay with altitude. I compare this distribution with that observed on the neighboring island of Sao Tome, also in the Gulf of Guinea. Overall, the distribution patterns of the two species are similar, but models indicate a higher abundance at sea level in Sao Tome than in Bioko. I used specimens from this survey to study temperature preference under controlled conditions. I found no significant differences between species or between sexes; however, I detected an altitudinal cline in temperature preference, with high-elevation populations preferring cooler temperatures on both islands. ConclusionsThese results indicate the presence of phenotypic variation in a key trait--temperature choice--that may alter the likelihood of contact between these vectors and humans.

Combining novel methodologies with ovarian dissection, we estimated life histories for ca. 90,000 individual female Glossina pallidipes and G. m. morsitans sampled from 1988-1999 in Zimbabwes Zambezi Valley. Using temperature-dependent development rates we stepped back through each flys life, fixing dates of successive pregnancies, adult emergence, pupal period, pregnancy and oogenesis. This enabled modelling of relationships between wing and egg lengths, and conditions prevailing when these lengths were being determined. Egg lengths increased with maternal wing length, were shorter in primiparous flies but changed little with age thereafter. G. pallidipes egg lengths were positively related to NDVI and negatively to temperature (R2 = 0.68), for variables averaged over the period of oogenesis for each fly, and then averaged again across weekly cohorts of flies. G. m. morsitans mean egg lengths, pooled by month, showed the same pattern (R2 = 0.53). Pooled mean wing lengths increased with NDVI and decreased with temperature prevailing while flies were developing in the ovaries and uterus; R2= 0.66 (G. pallidipes) and R2= 0.56 (G. m. morsitans). The models - fitted using flies captured after November 1991 - gave good predictions, with no further modeling, for egg and wing lengths of flies captured between September 1988 and November 1991. The models facilitate true predictions of future changes in fly size based on readily available meteorological data, benefiting vector and disease control efforts in predicting likely changes in tsetse population densities and distribution. Selection against small individuals in the hot-dry season is not restricted to teneral mortality continuing for some weeks after emergence. NDVI, measures of wetness and temperature can indirectly impact tsetse size, mortality and population density by affecting vertebrate host density and, thereby, the probability of tsetse locating and feeding on a host. Our methodology impacts numerous areas of vector biology and control.

BACKGROUNDAngola ranks among the five countries with the highest malaria burden globally. The Ministry of Health in Angola has consistently partnered with international donors to sustain entomological surveillance and vector control strategies in a context of high malaria burden. METHODSVector surveillance was carried out in Luanda, Benguela, Namibe and Cuanza Sul provinces from 2016-2022. Collected adult mosquitoes were tested to assess the presence of Plasmodium parasites and determine blood sources. Larvae collections provided live material to test insecticide susceptibility in local Anopheles populations. Taxonomic determination of mosquitoes was based on external morphology and confirmed with molecular assays. The presence of Anopheles azevedoi was confirmed through morphology and genetic sequences, and errors in the original species determination were detected, discussed and corrected. OBJECTIVESThe study aimed to update the geographical range of Anopheles azevedoi in Angola and monitor the species susceptibility to public health insecticides. FINDINGS and MAIN CONCLUSIONSWe report on populations of Anopheles azevedoi occurring along the western coast of Angola, a highly abundant species with anthropophilic behavior in urban areas. Anopheles azevedoi is widely resistant to pyrethroids and DDT but fully susceptible to chlorfenapyr. We contribute with COI and ITS-2 barcoding sequences for future species identification and explain the reasons for which this species has been for long misidentified in Angola.

Bird blowflies, Protocalliphora spp. (Diptera: Calliphoridae), are prevalent ectoparasites of altricial bird nestlings across the Holarctic region. Yet, their spatial and temporal dynamics of infestations, species composition, and interactions with parasitoids remain poorly understood. We present a 16-year (2004-2019) multisite study of bird blowfly infestations based on 2673 tree swallow, Tachycineta bicolor (Vieillot) (Passeriformes: Hirundinidae), nests collected across a 10 200-km{superscript 2} gradient of agricultural intensity in Quebec, Canada. Nest infestation prevalence and parasitic load varied markedly across space and time but showed synchronous recurrence at approximately 75% of sites, suggesting the influence of regional and local processes. Yearly rates of parasitoidism of bird blowfly puparia by Nasonia spp. wasps (Hymenoptera: Pteromalidae) were high but variable (48-90%), likely contributing to the temporal fluctuations in bird blowfly prevalence and load. Substantial interannual shifts in the relative abundance of Protocalliphora species (P. bennetti, P. metallica, and P. sialia) emphasised the importance of species-level identification in bird blowfly ecological studies. Large overlap in puparia size among species challenged the utility of traditional diagnostic traits for species identification. Finally, dormancy or mortality of Nasonia spp. occurred in 3-16% of Protocalliphora spp. puparia, depending on year. These findings highlight the importance of long-term, multitrophic, and spatially explicit monitoring to unravel the drivers of host-parasite-parasitoid dynamics.

BackgroundThe malaria transmission potential and the vulnerability of Anopheles mosquitoes to different vector control methods depend, among other factors, on the endophily, endophagy, anthropophagy and survival of each species. Local information on these bionomic parameters is generally unavailable. MethodsTo address this, we estimated species-specific values of these parameters using an augmented version of the global database of bionomics data by Massey et al. (2016). We applied inclusion and exclusion criteria to select eligible studies with relevant experimental designs that minimise bias from collection methods for parous, sac, endophagy, and endophily rates as well as for the resting duration. For the human blood index (HBI), we separated data from indoor and outdoor collections. We fitted hierarchical Bayesian models with levels based on Anopheles taxonomy to estimate these quantities. Based on the estimated bionomics, we quantified the expected vectorial capacity reduction after the introduction of a pyrethroid-pyrrole insecticide-treated net (ITN) for 57 Anopheles species. ResultsWe identified 26 eligible studies for endophagy and 61 for the parous rate, leading to a Bayesian posterior average for the Anopheles genus of 42% (95% credible interval: 18-70) and 55% (32-77) respectively. HBI values widely varied depending on the location of collection, except for some species showing strong anthropophilic behaviours. Resting duration was estimated to be 2.1 days (1.2 - 4.8) at the genus level. Few studies were available to estimate the sac and endophily rates, which prevented us from deriving precise estimates for the whole Anopheles genus. Our estimates of the vectorial capacity reduction following the introduction of a pyrrole-pyrethroid ITN ranged between 48% and 76% across species, highlighting the important differences among mosquito species in vulnerability to vector control interventions. ConclusionThis work demonstrates how data from both Anopheles species complexes and individual species can be leveraged to generate species-specific estimates of bionomic parameters, capturing the local characteristics and behaviour of malaria vectors. The dataset is readily updatable as new data become available. However, more frequent and standardised field surveys are still needed to accurately characterise local vector behaviour.

Black soldier fly larvae (BSFL) have quickly become one of the most farmed animals in the world. However, little is known about how to monitor stress and welfare in these animals. The difficulty of welfare assessment is compounded by the fact that BSFL live in their feed and prefer darkness. This behaviour makes it challenging to observe potential welfare indicators without inducing stress via disturbing the larvae or moving them into the light. However, acoustic devices may be able to pick up signatures of stress in the population even while they are out of sight, allowing for remote monitoring of animals in natural conditions (in the feed and/or in the dark). Acoustic monitoring of this type has been deployed for the detection of insects in stored grains, suggesting this method holds some promise for assessing insect behavioural signatures. In this study, we aimed to identify general, acoustic signatures of stress in BSFL by recording them during exposure to two stressors (light or shaking) or in a low-stress control condition. Our data suggest there are consistent differences in the acoustic recordings of the non-stressed and stressed conditions that may indicate the animals behaviours shift consistently in response to stress. Ultimately, the data suggest acoustic monitoring may hold promise for larval behaviour and/or welfare assessment and should be further explored in response to a variety of stressors across the larval life stage.

BACKGROUNDThe two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest with a rapid propensity for developing acaricide resistance. Bifenazate targets mitochondrial cytochrome b (CYTB). While the G126S mutation is frequently associated with resistance, its independent role remains unclear as it often occurs with other substitutions. This study explores the molecular basis of bifenazate resistance in a Russian laboratory strain derived from a St. Petersburg greenhouse population. RESULTSDisruptive selection with increasing bifenazate concentrations generated resistant and susceptible isofemale lines. AlphaFold2 structural modeling of CYTB indicated that G126S causes a steric clash, leading to conformational destabilization, whereas other reported mutations primarily affect the ligand-binding pocket. Oxford Nanopore sequencing revealed a very low initial frequency of the G126S allele (<1%; 226/35,895 reads) in the unselected population. After one year of stepwise selection (0.00005-0.031% a.i.), the mutant allele frequency surged to 90% (7,272/8,056 reads). No other known resistance-associated mutations were found in the analyzed cytb fragment. CONCLUSIONWe report the first identification of the G126S mutation in a Russian T. urticae population and demonstrate its rapid fixation under bifenazate selection. Within this genetic background, G126S alone appears sufficient to confer high-level resistance, emphasizing the population-specific nature of resistance evolution and the critical need for local monitoring.

BackgroundAnopheles mosquitoes vector pathogens responsible for more than 600,000 human deaths annually. Ecological studies of these insects are important to guide effective vector-control campaigns and to understand their broader ecological consequences. Molecular ecology methods, particularly qPCR, provide a valuable tool in such studies. By detecting trace DNA of a taxon of interest within mixed or environmental samples, qPCR can facilitate identification of prey taxa of interest in the diets of consumers. However, no protocol for the detection of An. gambiae complex mosquitoes in dietary samples has been available. MethodsWe introduce a new set of qPCR primers (Agam_CO1_F1 and Agam_CO1_R1) and a probe-based assay for detection of Anopheles gambiae-complex mosquitoes, even with short reads common in dietary and environmental samples. The primers were tested in vitro for their specificity and sensitivity, and in silico using Primer-BLAST to assess potential off-target amplification. ResultsThe qPCR primers amplified An. gambiae DNA even at low starting concentrations (5 copies {micro}l-1). The primers did not amplify any non-target DNA in either the in vitro or in silico tests, but consistently amplified An. gambiae complex DNA. The primers can therefore provide reliable tests for the presence or absence of An. gambiae complex in dietary or eDNA samples. ConclusionsThe new qPCR primers should allow advances in research into mosquito ecology by allowing detection of even trace amounts of An. gambiae DNA in dietary and environmental samples. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=72 SRC="FIGDIR/small/707393v1_ufig1.gif" ALT="Figure 1"> View larger version (11K): org.highwire.dtl.DTLVardef@1fcce3corg.highwire.dtl.DTLVardef@47e5f5org.highwire.dtl.DTLVardef@4a7063org.highwire.dtl.DTLVardef@1188d60_HPS_FORMAT_FIGEXP M_FIG C_FIG

The tropical house cricket Gryllodes sigillatus is a major species used in the edible insect farming industry. Despite the rapid expansion of this sector, diagnostic tools for detecting infections in these species remain limited. The lack of validated reference genes compromises the reliability of RT-qPCR-based gene expression analyses, which are essential for the development of molecular tools for disease diagnosis and health monitoring in insect production systems. To address this gap, we evaluated the expression stability of six candidate reference genes (ACTB, EF1, GAPDH, HisH3, RPL5, and 18SrRNA) across four body parts (abdomen, head, legs, and whole body) using a combination of complementary statistical approaches, including geNorm, NormFinder, BestKeeper, the {Delta}Ct method, the R statistical environment, and the integrated RefFinder tool. Candidate genes were identified and annotated using the recently published G. sigillatus genome, through sequence comparisons with closely related insect species using BLAST and reciprocal BLAST analyses, multiple sequence alignments. All procedures complied with MIQE 2.0 guidelines to ensure methodological rigor and transparency. The results showed that ACTB, EF1, RPL5, and 18SrRNA exhibited stable and consistent expression across all analyzed tissues, whereas GAPDH and HisH3 displayed high variability and were generally unsuitable for normalization, except in head tissue where GAPDH remained stable. This study provides the first validated set of reference genes for G. sigillatus, establishing a robust foundation for accurate, reproducible, and comparable gene expression analyses. Furthermore, these findings support the development of RT-qPCR-based diagnostic tools, contributing to improved health monitoring and biosafety in insect production systems.

PurposeAnopheles stephensi is a malaria mosquito vector that has been raising international concern due to its invasive nature in Africa, including the nation of Djibouti. Since its initial detection in Djibouti in 2012, malaria morbidity and mortality have increased exponentially in the county. While there is an observed association increase in human malaria cases since the arrival of An. stephensi, high-quality evidence of An. stephensi carrying infective sporozoites is essential to determine the role of the invasive vector in malaria dynamics in Djibouti. This study seeks to confirm the link between An. stephensi and malaria transmission in Djibouti and examine genetic relatedness between Djiboutian An. stephensi populations and populations across the Horn of Africa. Such information regarding the An. stephensi populations and the Plasmodium species they transmit is necessary to devise appropriate control strategies and limit malaria transmission within and beyond the country. MethodsOne hundred and ninety-six adult An. stephensi mosquitoes from Djibouti were collected, molecularly confirmed, analyzed for a portion of the cytochrome c oxidase subunit 1 (COI), and tested for infective sporozoites using a highly sensitive and specific multiplex circumsporozoite enzyme linked immunosorbent assay (csELISA) bead assay. The COI sequences of one hundred and fourteen samples were further used to characterize the population genetic structure of the sampled An. stephensi and its genetic relatedness to other An. stephensi populations across the Horn of Africa. ResultsAll 196 samples were morphologically and molecularly confirmed to be An. stephensi. Plasmodium vivax210 sporozoites were detected with a positivity rate of 1.02%. An analysis of the COI region showed that the infected An. stephensi have the most prevalent COI haplotypes of invasive An. stephensi circulating in the Horn of Africa. ConclusionsThe findings from this study confirm the involvement of An. stephensi in P. vivax transmission in Djibouti and describe the genetic relatedness of Djiboutian An. stephensi populations to other populations across the Horn of Africa. This highlights the threat of An. stephensi invasion and supports a rapid and comprehensive response to mitigate the harm that An. stephensi populations cause, particularly through surveillance and control of adult populations. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=119 SRC="FIGDIR/small/707780v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@19f762corg.highwire.dtl.DTLVardef@7624forg.highwire.dtl.DTLVardef@c7492borg.highwire.dtl.DTLVardef@194c11f_HPS_FORMAT_FIGEXP M_FIG C_FIG

Accurate species identification is crucial to assess the medical and veterinary relevance of a mosquito specimen, but it requires high experience of the observers and well-equipped laboratories. This study aimed to evaluate whether low-cost imaging in combination with geometric wing morphometrics can provide accurate identification of invasive, morphologically similar Aedes species. The right wings of 670 female specimens covering 184 Ae. aegypti, 156 Ae. albopictus, 166 Ae. j. japonicus and 164 Ae. koreicus, were removed, mounted and photographed with a professional stereomicroscope (Olympus SZ61, Olympus, Tokyo, Japan) and a macro lens (Apexel-24XMH, Apexel, Shenzhen, China) attached to a smartphone. The coordinates of 18 landmarks on the vein crosses were digitalized by a single observer for each image. In addition, the landmarks of 20 specimens per species and imaging device were digitalized by six different observers to assess the degree of the observer error. The superimposed shape variables were used to compare the species classification accuracy of linear discriminant analysis (LDA), support vector machine (SVM), Random Forest (RF), and XGBoost. In the single-observer landmark data, the LDA achieved the best classification results with a mean accuracy of 95 % for landmarks from microscope images and 92 % for those obtained from smartphone images. In the multi-observer landmark data, LDA consistently performed worse than the other three classifiers, and the reduction in the accuracy was more pronounced for smartphone images than for microscope images. This pattern was associated with a higher degree of observer error for smartphone images, as confirmed by a landmark-wise comparison across all landmarks. Geometric wing morphometrics provides a reliable method to distinguish the most common invasive Aedes species in Europe. Thereby, the image quality obtained by smartphones equipped with a macro lens is sufficient and represents a cost-effective alternative to professional microscopes. However, due to the greater degree of observer variation for smartphone images, landmark coordinates for such images should ideally be collected by a single observer.

Triatomine bugs are blood feeding insects that transmit the parasite Trypanosoma cruzi, causative agent of Chagas disease. The bugs are found primarily in the Americas with a few species in Asia and Africa. Here we report the first case of a live triatomine bug in Europe, found in a Lisbon hotel room. In August, 2025, the hotel room occupants discovered a triatomine bug perched on the headboard of their bed. Upon capture, bright red blood emerged from the bug; the occupants suspected that it had bitten them during the night. The bug was identified morphologically as triatomine species Hospesneotomae protracta, which was confirmed molecularly. Hospesneotomae protracta is native to the southwestern United States where it is a competent T. cruzi vector. Trypanosoma cruzi was not detected in this specimen. Although this case likely represents an accidental importation, it illustrates the ease with which disease vectors can be unknowingly transported globally. Ergo it is crucial to document and share these findings to prevent introductions of non-native arthropods of medical importance.

Climate change driven saltwater intrusion is expanding coastal brackish water habitats, promoting the proliferation of salinity-tolerant mosquitoes such as Culex sitiens, a vector of lymphatic filariasis and Japanese encephalitis. This study investigated whether environmental salinity affects mosquito morphology, specifically proboscis length, a trait of ecological significance related to feeding efficiency and vector competence. Late fourth-instar larvae and pupae of Cx. sitiens were collected from habitats with varying salinity levels in the Muttukadu Backwater, Tamil Nadu, India, and reared under controlled conditions using habitat specific water. Adult female body and proboscis lengths were measured, and water quality parameters were analysed to characterize environmental variation. Statistical analyses (Welchs ANOVA, regression, and ANCOVA) revealed a significant positive relationship between salinity and body length (R2 = 0.94, p=0.0003) as well as with proboscis length (R2 = 0.90, p=0.001). Additionally, ANCOVA indicated that the proboscis elongation remained significant after adjusting for body length (F{square}, {square}{square}{square} = 32.36, p < 0.001, partial 2 = 0.257). This confirmed that the salinity exerts an independent effect on this morphological trait. These findings provide the first field-based evidence that the environmental salinity drives proboscis elongation in Cx. sitiens, indicating an adaptive response under saline stress. This may have implications for disease transmission in climate-affected coastal regions.

Istocheta aldrichi (Diptera: Tachinidae) is a specialist parasitoid of the invasive Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae). Research and releases for biological control depend on field collecting parasitized hosts and rearing the parasitoid through diapause to obtain I. aldrichi adults. This study investigated how rearing practices before, during and after the seasonal overwintering period affected the proportion of I. aldrichi pupae that emerged as adults, the timing of parasitoid emergence, and their longevity. Increasing cold exposure duration during overwintering increased adult I. aldrichi emergence from puparia and reduced development time after transfer to warm conditions. Adult I. aldrichi emergence from overwintered puparia depended on interactions between overwintering environment (indoors vs. outdoors), spring thermal regime, and the timing of host collection in the previous season. Burying puparia in the soil in late summer/early fall resulted in higher subsequent adult I. aldrichi emergence. Manipulating spring temperatures in controlled environments allowed parasitoid emergence to be staggered over several weeks without reducing emergence success. Emergence under outdoor spring conditions was unreliable. Adult longevity was affected by temperature and diet: cooler conditions extended lifespan, honey-water increased longevity relative to pollen alone or honey-water and pollen together. These results provide a foundation to further improve I. aldrichi rearing techniques for use in experimental research and applied biological control of P. japonica.

Ultra-low volume (ULV) insecticide spraying with deltamethrin as the active ingredient is widely used in mosquito control programs, yet its effectiveness against target mosquitoes and its ecological side effects remain poorly quantified under field conditions in Central Europe. Here, we experimentally evaluated the short-term impact of ground ULV spraying on both mosquito populations and non-target flying insects in Hungary using a paired before-after-control-impact (BACI) design. Mosquitoes were sampled with BG Sentinel traps, while non-target insects were collected using malaise traps. ULV treatment resulted in a significant reduction in mosquito abundance at treated sites, with an average decline of approximately 45%. Native and invasive mosquito species, including Aedes albopictus and Aedes koreicus, showed similar proportional decreases. However, treatment effectiveness varied substantially among sites and was influenced by initial mosquito abundance and wind conditions. In parallel, malaise trap samples revealed a marked decline in non-target flying insects, with reductions exceeding 40% across multiple taxonomic groups, particularly among small- and medium-sized insects, and also when considering pollinator taxa together. Our results indicate that while ULV spraying can temporarily reduce mosquito abundance, it also imposes considerable short-term impacts on non-target insect communities, highlighting trade-offs between vector control and insect conservation within mosquito management programs.

West Nile virus (WNV) transmission risk is typically estimated from pooled whole-mosquito infection data, which may overestimate the proportion of mosquitoes capable of transmission. To assess natural viral dissemination in field-collected Culex tarsalis, we tested infection rates in tissues of 1,793 individual mosquitoes collected from Northern Colorado in August 2023. Abdomens were screened for WNV RNA, and corresponding thorax and head tissues from positive mosquitoes were tested. Fifteen mosquitoes had detectable abdominal infections, but WNV RNA was detected in only 53% (8/15) of both the thorax and head tissues, while another 27% (4/15) had WNV RNA detected in either the thorax or the head alone. Logistic regression suggests an inconsistent relationship between abdominal viral ribonucleic acid (RNA) load and virus dissemination, whereas receiver operating characteristic analysis identifies a threshold of [~]59,000 RNA copies in the abdomen predictive of dissemination (AUC 0.80, 95% CI: 0.545, 1). These results suggest whole-body RNA detection may overestimate transmission potential from field-captured mosquitoes, and that incorporating infection data could refine surveillance-based risk indices for WNV.

Schistosomiasis is a neglected disease that is still ravaging many rural community dwellers in Nigeria. Different species of freshwater snails, such as Bulinus and Biomphalaria, play passive roles in the transmission of schistosomiasis. A study on the occurrence of snail intermediate hosts of schistosomes was conducted following mass praziquantel administration in Katsina-Ala, Benue State, Nigeria. The objective was to determine the prevalence of freshwater snails. incriminated in transmitting schistosomiasis and their cercaria infectivity. A total of 24,812 freshwater snails belonging to six different genera (Bulinus globosus, B. forskalii, Pila ovata, Lanistes lybicus, Biomphalaria pfeifferi, and Lymnaea natalensis were encountered. Snails collected were kept under laboratory conditions for cercaria emergence. B. globosus, B. forskalii, and B. pfeifferi were identified as vectors of Schistosomes because they secreted cercaria of S. haematobium and S. mansoni, respectively. Parasite infection was higher in the ponds (83.33 %); followed by dams (68.57 %)) and streams (53.33 %). There was positive correlation (r = 0.657; P < 0.05) between the amount of rainfall and abundance of all snail species and their infection rate collected except Biomphalaria species that showed a negative correlation. The studies, therefore, call for Consideration of snails control to be integrated with Praziquantel Mass Drug Advocacy Campaigns so as to achieve transmission interruption.

Istocheta aldrichi (Diptera: Tachinidae), a specialist parasitoid of the invasive Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), was released to eastern North America in the 1920s as part of a classical biological control program. Further releases are being considered in different regions of North America and Europe where P. japonica is establishing. Successful releases of the biocontrol agent depend on identifying efficient techniques for collecting parasitized hosts from the field and rearing the parasitoid through diapause to obtain I. aldrichi adults. In this study, we evaluated how the collection date, the collection method (hand-picking vs. regular traps vs. modified traps) and rearing conditions (food provision and substrate type) of parasitized hosts influence I. aldrichi pupariation and emergence. The proportion of parasitized beetles yielding I. aldrichi puparia decreased considerably as the season progressed. Rearing conditions immediately after collection influenced both puparium yield and quality: withholding food from parasitized P. japonica slightly increased puparium yield but reduced puparium weight, while the effect of food provision on subsequent overwintering survival depended on rearing substrate. Finally, simple modifications to commercial traps (larger, ventilated, containers with added food source and substrate) collected more beetles than regular traps and promoted successful development of the parasitoid to the puparium stage. Our results are used to suggest basic guidelines for collecting and rearing I. aldrichi in experimental research and applied biological control of P. japonica.

RNA viruses are common in tephritid fruit flies including the Queensland fruit fly, Australias most significant horticultural pest. For many their transmission, tissue tropism and load across host development remain unexplored. Yet these factors are important for host biology, ecology and pest management. We investigated Bactrocera tryoni orbivirus (OV), Bactrocera tryoni xinmovirus (XV), Bactrocera tryoni toti-like virus (TLV) and Bactrocera tryoni iflavirus species 2 (IVsp.2) that commonly coinfect B. tryoni laboratory populations. OV and XV transmission was vertical within and on eggs, while TLV transmission was vertical within eggs. IVsp.2 was not detected in eggs but was present in adults; however, IVsp.2 was horizontally transmitted, with viral load increasing with cohabitation time with infected flies. Horizontal transmission was not observed for the other viruses. OV had a similar load across all tissues, while XV was consistently more abundant in ovaries. TLV had a high viral load in the brain whereas IVsp.2 was abundant in the thorax, foregut and midgut. Besides differences in eggs, the viruses were detected in all other developmental stages, but viral load patterns differed: viral load remained constant for TLV, fluctuated for OV and XV, and was low in pre-adult stages and high in adults for IVsp.2. Our findings demonstrate distinct transmission strategies and tissue tropism among the viruses, providing new insights into their epidemiology and role in host biology. Furthermore, contrary to prevailing views that viruses are generally horizontally transmitted, most known RNA viruses of B. tryoni are vertically transmitted affecting the evolution of host-virus interactions.