Triatominae are associated with various Brazilian habitats, including bird nests, animal burrows, and peridomestic structures. Despite extensive studies on triatomines in domiciliary environments in Ceará, Brazil, there...Triatominae are associated with various Brazilian habitats, including bird nests, animal burrows, and peridomestic structures. Despite extensive studies on triatomines in domiciliary environments in Ceará, Brazil, there has been limited research on their presence in the wild. This study focuses on the municipality of Morrinhos in Ceará, which is characterized by a Caatinga biome and riparian forests along the Acaraú River. During the study, a total of 185 nests of were analyzed in rural locations and triatomines were collected in 26 nests from 12 different locations. A total of 117 triatomines was collected, belonging to three species: , , and . was the only species found in a nest inhabited by . Nests of serve as shelters for various animals, providing an ideal environment for triatomines to establish colonies due to their proximity to food sources and their generalist feeding habits. The incorporation of anthropogenic materials by birds in nest construction can indirectly affect the presence of other animals that may serve as food sources for triatomines. Understanding the interactions between triatomines, birds, and their habitats is essential for assessing the risks associated with triatomine infestation in wild ecosystems.
For the sibling mosquito species Say and Cockerell, success of offspring is highly dependent on oviposition site selection by gravid females, and the dynamics of that selection process have been the subject of much inv...For the sibling mosquito species Say and Cockerell, success of offspring is highly dependent on oviposition site selection by gravid females, and the dynamics of that selection process have been the subject of much investigation. Patterns of vertical oviposition stratification were examined in this study by placing basal and canopy level oviposition traps in relatively steep and flat terrains, as well as in flood-prone riverbank vs upland settings. Strong stratification existed in both steep and flat terrains, with favoring basal ovitraps and favoring canopy ovitraps. Contrary to expectations, displayed even more marked preference for canopy ovitraps in steeper terrain. Both species avoided basal ovitraps in flood-prone locations, where oviposited only in canopy ovitraps and greatly outnumbered in canopy ovitraps. In contrast, the expected stratification was found in nearby upland habitats.
Lyme disease is the most prevalent vector-borne disease in the U.S., and acaricidal feeds administered to white-tailed deer () have potential to disrupt blood feeding by the blacklegged tick, . Two studies were conducted...Lyme disease is the most prevalent vector-borne disease in the U.S., and acaricidal feeds administered to white-tailed deer () have potential to disrupt blood feeding by the blacklegged tick, . Two studies were conducted with the aim of determining an ideal formulation to deliver oral acaricides to white-tailed deer and finding the lowest fipronil dose level to effectively control . During formulation screening, various commercial attractants (baits) were presented to deer in large paddocks under semi-field conditions and motion-sensitive cameras were used to monitor consumption by deer and non-target species. During dose range-finding, deer were housed individually and presented a fipronil feed at one of five dose levels for 48 h (two deer untreated). At 24 h post-exposure, the deer were anesthetized, blood was drawn, and deer were manually infested with 20 mating pairs in feeding capsules. Tick mortality was monitored up to nine days post-attachment. Results of formulation screening indicated that loose/granular formulations were substantially more palatable to deer, relative to block formulations, and would be more effective under field conditions. Dose range-finding concluded fipronil feeds with doses of 25 ppm and higher would eliminate 100% of parasitizing deer. Additionally, 10 ppm fipronil feed controlled a considerable proportion of ticks, and results suggested 100% ticks could be eliminated if fipronil sulfone was present in plasma at ≥25.1 ppb. These results were paramount in developing a low dose fipronil deer feed for tick control and should provide valuable insights prior to execution of future field trials.
White-footed mouse () populations can thrive in fragmented suburban and urban parks and residential spaces and play a pivotal role in the spread and prevalence of tick-borne diseases. We collected spatial data on 58 indi...White-footed mouse () populations can thrive in fragmented suburban and urban parks and residential spaces and play a pivotal role in the spread and prevalence of tick-borne diseases. We collected spatial data on 58 individual mice living at the intersection of county park land and residential land in suburban Howard County, MD, U.S.A. We analyzed mouse density, home-range size and overlap, and a Bayesian mixed-effects model to identify the habitats where they were found relative to where they were caught, as well as a resource selection function for general habitat use. We found that as mouse density increased, home-range size decreased. The overlap indices and the resource selection function supported territoriality coupled with site-specific space use in these suburban mouse populations. While mice occurred in open areas, forest edge, and forest, they showed a strong preference for forested areas. Interestingly, mice captured only 30 to 40 m into the forest rarely used the nearby private yards or human structures and this has direct implications for the placement of rodent-targeted tick control treatments. Our study supports the need for zoonotic disease management frameworks that are based on site-specific land cover characteristics as well as specific management objectives.
Controlling mosquito-borne disease is a major global challenge due to the rise of insecticide-resistant mosquitoes. In response, we conducted a study in Chiang Mai Province, Thailand, which is one of the largest and the...Controlling mosquito-borne disease is a major global challenge due to the rise of insecticide-resistant mosquitoes. In response, we conducted a study in Chiang Mai Province, Thailand, which is one of the largest and the most popular cities for tourists in Southeast Asia, to explore the potential of local species as biological control agents for mosquito larvae. Mosquito larvae and aquatic predators were sampled from large and small habitats, while relevant physico-chemical parameters were measured. The study identified 560 predators and 1,572 mosquitoes, with most mosquito species belonging to the genus . Additionally, the study identified 16 predator taxa, including four fish taxa and 12 taxa of predatory aquatic insects belonging to four orders: Coleoptera, Hemiptera, Odonata, and Diptera. The study found that several locally occurring predator species, namely , , , , , and , shared habitats with mosquitoes, indicating their potential as effective biological control agents for mosquito control. Conductivity, dissolved oxygen, and pH were the important physico-chemical parameters that affect both predators and mosquito larvae. Consequently, promoting native predators and reducing mosquito larvae through habitat management would be a sustainable and ecologically friendly approach in large habitats where it is not possible to remove mosquito oviposition sites. In smaller habitats, releasing local aquatic predators and removing oviposition sites may be a suitable strategy.
The effects of three larval diets (beef meat, chicken meat, and beef liver) on development of (Wiedemann) were evaluated. Egg hatching rates were higher on chicken meat and beef meat (99.5%) than on beef liver (96.5%)....The effects of three larval diets (beef meat, chicken meat, and beef liver) on development of (Wiedemann) were evaluated. Egg hatching rates were higher on chicken meat and beef meat (99.5%) than on beef liver (96.5%). Pupation success was higher on chicken meat (99.0%) and beef meat (98.0%) than on beef liver (87.1%). Adult emergence rates were higher in flies reared on chicken meat (99.0%) and beef meat (98.5%) than on beef liver (93.5%). Proportions of female flies were somewhat higher in flies reared on chicken meat or beef meat (54-56% female) than on beef liver (52.5%). Flies that were reared on chicken meat and beef meat had shorter egg-adult development times (16.3 days) than flies reared on beef liver (18.5 days), and the generation time of flies reared on chicken meat or beef meat (51-52 days) was several days shorter than flies reared on beef liver (54 days). Flies reared on chicken meat had larger ovaries and more ovarioles per ovary when larvae were reared on chicken than flies reared on beef meat or beef liver. The ovaries of flies reared on chicken meat had significantly higher amounts of protein (21 mg/g body weight) than flies reared on beef liver (12 mg). Analysis of the larval diets showed that beef liver had the lowest amounts of protein and carbohydrate of the three tested diets, whereas the amounts of lipids did not differ among the diets.
Chagas disease is one of the most important vector-borne diseases in Latin America. (Usinger), distributed in western Mexico, is one of the most important vectors of Chagas. Knowing the type and materials used for buil...Chagas disease is one of the most important vector-borne diseases in Latin America. (Usinger), distributed in western Mexico, is one of the most important vectors of Chagas. Knowing the type and materials used for building homes could lead to improved methods for controlling triatomines by focusing efforts on controlling every species of triatomine in its specific microhabitat. Houses in three studied localities of western Mexico that harbored were characterized, as well as two entomological indices. Infestation Index values varied from 10.8% to 51.9% in the three localities, whereas Natural Infection Index values varied from 18.1% to 35.2%. Characteristics of houses invaded by also varied. In Juan Gil Preciado, with the highest Entomological Index values, most houses were built of adobe walls with a roof of clay tiles and a dirt floor, and included the presence of domestic animals. Our data indicate that the potential risk of infection with differs markedly for inhabitants of the three studied localities, which demonstrates the importance of studying local populations of triatomines. Our study should contribute to decision-making regarding triatomine control efforts by providing profiles of houses that are more susceptible to triatomine invasion.
Ticks are vectors of many zoonotic pathogens of clinical relevance, including and species. Since few data about these tick-borne pathogens are available in the Canary Islands, the aim of the present study was to screen...Ticks are vectors of many zoonotic pathogens of clinical relevance, including and species. Since few data about these tick-borne pathogens are available in the Canary Islands, the aim of the present study was to screen their presence in questing and feeding ticks on the island of Tenerife. A total of 81 ticks was removed from six hedgehogs, and eight ticks were collected from the grass. PCR assays for tick species identification based on the LSU rRNA gene, and detection of spp. and spp. by targeting the 16s rRNA and gene, respectively, were carried out. and tick species were identified, with detected in In addition, and one unidentified species were detected. The overall prevalence of in ticks was 12.2%, and none harbored sp. This work constitutes the first identification in the Canary Islands of pathogenic and the species of unknown pathogenicity in questing ticks. The clinical relevance of the pathogens identified highlights the need for studies with increased sample size and locations, including potential hosts, as well as warning the population about the relevance of ticks as vectors.
We developed a biological control method directed toward using the release of -contaminated males to spread the fungus to wild females. A generalized Poisson model was used to relate marked females (MKF) to -exposed ma...We developed a biological control method directed toward using the release of -contaminated males to spread the fungus to wild females. A generalized Poisson model was used to relate marked females (MKF) to -exposed males (FEM). In a mark-recapture parallel arm trial, FEM release was a better predictor than unexposed male (UM) releases to forecast MKF by FEM. Total females (TF), marked males (MKM), and wild males (WM) as predictors were counted in human-landings in 15 households treated with 40 FEM each, vs 40 UM released/household/week in 15 households for eight weeks. Fit of MKF to standard, generalized Poisson (GP), and negative binomial models/arm built by TF, MKM, WM, and interactions as predictors were computed. In both arms, MKF was better modeled by GP, which in treated, all but one of the eight observed data fell within the confidence intervals predicted by the model. However, the control GP had two outliers and MKM as a single predictor. Likewise, the pseudo-R measures of 95% and 46% for treated and control groups also showed that the GP with FEM was more suitable to predict MKF. It should thus be possible to use the GP model to indirectly estimate that an increase of one TF or one fungus-exposed male would increase the number of marked-females by 8% or 9%, respectively, while wild males were an irrelevant predictor to the model.
Mosquito larvicides are used across a variety of aquatic habitats, although when applied they likely affect other aquatic organisms. The removal or impairment of top insect predators via larvicides could be beneficial to...Mosquito larvicides are used across a variety of aquatic habitats, although when applied they likely affect other aquatic organisms. The removal or impairment of top insect predators via larvicides could be beneficial to mosquitoes by allowing their populations to rebound once pesticide levels dissipate. Our goal was to determine if two larvicide types, growth regulators (IGRs) and surface films (SFs), harm non-target aquatic insect communities, and if these chemicals influence the ability of predatory aquatic insects to regulate mosquitoes. We surveyed aquatic sites before and after IGR and SF-application, then compared changes in insect community structure. Evenness was lower in SF treated habitats, and when analyzing prey/controphic taxa only, evenness and diversity changed in untreated reference areas, suggesting that differences measured were due to other environmental factors, not larvicide presence. A field experiment was then conducted by exposing specific predatory aquatic insects to varying doses of IGRs and SFs and then placing them in mesocosms containing mosquito larvae. Surface films were directly lethal to adult dytiscids at recommended and high concentrations. Although we found no significant differences in mosquito emergence among all treatment levels, there was a trend of negative controls (no predator mesocosms) and SF-treated predators allowing the most mosquitoes to emerge compared to positive controls (predators not exposed to larvicides) and IGR-treated predators. Thus, these larvicides may have minimal effects on mosquito larvae predators, but the direct effects of surface films on insects that interact with the water's surface require further investigation.
Two independent studies were conducted in northeastern Florida to determine if Biogents Gravid Trap (GAT) mosquito collections could be enhanced with a variety of substances and structural configurations. The first stud...Two independent studies were conducted in northeastern Florida to determine if Biogents Gravid Trap (GAT) mosquito collections could be enhanced with a variety of substances and structural configurations. The first study baited GATs with either: 1) an infusion of mixed Southern live oak leaf () and slash pine needle () litter, 2) Biogents Lure (BG Lure), 3) yeast-derived carbon dioxide), 4) yeast-derived carbon dioxide+ BG Lure, or 5) a combination of all three. Nine mosquito species were collected from traps in the first study with >> as the top four most abundantly collected species. No significant difference in mosquito abundance was observed among these species among treatments. However, when the overall number of mosquitoes for all nine species was pooled, GATs baited with the combination of yeast-derived carbon dioxide + BG Lure + leaf infusion numerically collected the greatest number of individuals compared with the other four treatments. The second study evaluated the separate and combined attractiveness of individual GAT structural components/configurations with and without Southern live oak leaf litter infusion and BG-Lure. , , and were collected from all these traps in the second study. Results generally revealed that the current commercially available GAT configuration consisting of a screened translucent top (with BG-Lure) fitted into the black reservoir baited with oak leaf infusion remained the most attractive combination for collecting northeastern Florida mosquitoes.
Despite increasing severity and frequency of wildfires, knowledge about how fire impacts the ecology of tick-borne pathogens is limited. In 2018, the River Fire burned a forest in the far-western U.S.A. where the ecology...Despite increasing severity and frequency of wildfires, knowledge about how fire impacts the ecology of tick-borne pathogens is limited. In 2018, the River Fire burned a forest in the far-western U.S.A. where the ecology of tick-borne pathogens had been studied for decades. Forest structure, avifauna, large and small mammals, lizards, ticks, and tick-borne pathogens (, , ) were assessed after the wildfire in 2019 and 2020. Burning reduced canopy cover and eliminated the layer of thick leaf litter that hosted free-living ticks, which over time was replaced by forbs and grasses. Tick abundance and the vertebrate host community changed dramatically. Avian species adapted to cavity nesting became most prevalent, while the number of foliage-foraging species increased by 83% as vegetation regenerated. Nine mammalian species were observed on camera traps, including sentinel (black-tailed jackrabbits) and reservoir hosts (western gray squirrels) of One sp. mouse was captured in 2019 but by 2020, numbers were rebounding (n=37), although tick infestations on rodents remained sparse (0.2/rodent). However, western fence lizards (n=19) hosted 8.6 ticks on average in 2020. Assays for pathogens found no in either questing or host-feeding ticks, DNA in 4% (1/23) in 2019, and 17% (29/173) in 2020 for questing and host-feeding ticks combined, and DNA in just 1% of all ticks collected in 2020 (2/173). We conclude that a moderately severe wildfire can have dramatic impacts on the ecology of tick-borne pathogens, with changes posited to continue for multiple years.
Vector control has been an essential strategy in Brazil to manage vector-borne diseases, and the use of insecticides plays an important role in this effort. Pyriproxyfen (PPF) has become a common insect growth regulator...Vector control has been an essential strategy in Brazil to manage vector-borne diseases, and the use of insecticides plays an important role in this effort. Pyriproxyfen (PPF) has become a common insect growth regulator used to control juvenile stages of mosquitoes by disturbing their growth and development. This study assesses the susceptibility and resistance status of Brazilian populations that previously showed low resistance levels to PPF. Eggs of were collected from six cities located in the northeast states of Ceará (Quixadá, Icó, and Juazeiro do Norte), and Bahia (Itabuna, Brumado, and Serrinha). We used the Rockefeller strain as an experimental control and a strain known to be susceptible to insecticides. Inhibition of emergence rates by 50% of populations varied from 0.0098-0.046 µg/L. Mosquitoes from Icó, Serrinha, and Brumado showed low resistance levels [resistance ratio (RR) = 2.33, 4.52, and 4.83, respectively], whereas moderate levels of resistance were detected in populations from Juazeiro do Norte (RR=5.83) and Itabuna (RR=7.88). collected from the Quixadá population showed a high resistance level to pyriproxyfen (RR=11). The evolution of resistance in Brazilian populations to PPF can compromise vector control efforts. Continuous monitoring of insecticide resistance in is essential for making timely management decisions for effective vector control and management.
Natural and artificial water-filled containers serve as development sites for several larval Dipterans, including medically important mosquito species and biting midges. Containers are discrete habitats with limited car...Natural and artificial water-filled containers serve as development sites for several larval Dipterans, including medically important mosquito species and biting midges. Containers are discrete habitats with limited carrying capacity and high levels of both intra- and interspecific competition. While the outcomes of the interactions between mosquito species, particularly native and introduced , have been well described, competition between mosquitoes and other taxa, including , is largely unstudied. To determine the extent of shared resource use between container-inhabiting mosquito and biting midge species, we surveyed water-filled natural and artificial container habitats in Washington County, AR. Larvae were collected from containers in the field and reared in the laboratory until the adult stage, where they were identified to species. , the only species identified, co-occurred with four mosquito species, including the invasive . larvae were more common in natural than artificial containers. Natural container samples from which emerged were significantly less likely to harbor larvae than samples where that mosquito species was absent, suggesting the possibility that competes either directly or indirectly with other native taxa beyond congeners. Further research is needed on the nature of the interactions between and native spp.
is an exclusive and widely distributed species in Mexico and one of the three main vectors that transmit Chagas disease in the country. The state of Hidalgo is an endemic area for Chagas disease where the presence of sev...is an exclusive and widely distributed species in Mexico and one of the three main vectors that transmit Chagas disease in the country. The state of Hidalgo is an endemic area for Chagas disease where the presence of several species of triatomines has been reported. The objective of our work was to describe the morphology, colonization process, and reproductive behavior of in Guadalupe, Tecozautla, two years after the first collection of a specimen in this region. A total of 28 specimens was collected at both domicile and peridomicile, showing a 17.8% infection rate. The main collection site was a woodshed, and despite the collection of adults in the dwelling, we did not find eggs, exuviae, or nymphs. One female monitored from collection day until death laid 566 eggs, with a hatching rate of 95%, showing an increase of oviposition when cohabited with a male. The results showed the capacity that has to infest areas (mainly human dwellings) when it settles down, which would imply a risk for the population that lives in the locality.