Interspecific associations between two mosquito species can lead to effects such as competition, species displacement, and species stability. To better understand Aedes albopictus (Skuse) and other Aedes species, we monitored eggs in artificial oviposition cups (ovitraps) within Knox County, TN, U.S.A., during the 2016 and 2017 mosquito seasons. In 2016, one black and one white ovitrap were placed at 18 sites for 21 weeks, while in 2017 black and white ovitraps baited with grass-infused or deionized water were placed at 11 sites for nine weeks. Eggs were identified to species and resulting counts were used to determine the degree of interspecific association using Cole's coefficients (C₇) and the degree of heterogeneity across space and time using generalized linear mixed models (GLMM). Here, Aedes mosquitoes are generally ovipositing in black cups with grass-infused water, and Ae. albopictus eggs co-occurred with other Aedes species more often than would be expected. Finding a positive significant interspecific association between Ae. albopictus and other Aedes eggs suggests that methods used to control Ae. albopictus may also control other Aedes mosquitoes. Finding that Ae. albopictus co-occurs with other Aedes mosquitoes warrants additional research to evaluate outcomes associated with co-occurrence within the study area.

The vertical dimension constitutes an important niche axis along which mosquitoes may adjust their distribution. Here, we evaluated whether the vertical distribution of container-inhabiting Aedes mosquitoes differs along a gradient of anthropogenic land-use intensity within an urban landscape. Using a pulley system, we hung oviposition cups at three heights (ground level, 4.5, and 9 m) and in three habitats: forest, park, and a built environment. We hypothesized that mosquito abundance and diversity would be highest in the least disturbed forest habitat, decrease in the park, and be lowest at the UNC-Greensboro campus. We also expected Aedes albopictus (Skuse) and Ae. triseriatus (Say) to mainly oviposit at ground level and Ae. hendersoni (Cockerell) at canopy height. Aedes albopictus was the most common species (68.8%) collected in all three habitat types and was the only species found in the built environment. In that habitat, Ae. albopictus exhibited a bimodal distribution with the lowest activity at the intermediate height (4.5 m). Aedes triseriatus (28.9%) did not differ in egg abundance between the forest and park habitats but did exhibit diverse vertical habitat use while avoiding the canopy in the park habitat. Aedes hendersoni (2.3%) was the most sylvatic species and oviposited only at ground level. Our results indicate that the vertical distribution of mosquitoes is affected by the type of habitat in which they occur, and that this variation could be driven via local-scale modification of microclimatic factors.

Babesia caballi and Theileria equi are widely recognized as causative agents of equine pirolasmosis (EP), an acute, sub-acute, and chronic disease of equines, with relevant economic impact on horse trade worldwide. Although several studies on EP prevalence from central Italy have been published, data on ticks responsible for its transmission are still lacking. In this study, we identified a potential competent vector, investigating main features of its ecology together with EP infection rates. A two-year sampling of questing ticks was carried out for the first time in Italy in an area known for high EP prevalence in horse sera, detecting the association between Rhipicephalus bursa and causative agents of EP. Most of the positive pools harbored a single infection (91.1%); mixed infections were also detected (8.9%). The infection rate for T. equi slightly decreased among years; B. caballi showed a lower, but increasing, infection rate. Tick phenology, climate variables, and peaks of EP prevalence indicated late May and second half of June as periods with the highest risk of new infections, especially during warm and dry days.

The number of recognized flea-borne pathogens has increased over the past decade. However, the true number of infections related to all flea-borne pathogens remains unknown. To better understand the enzootic cycle of flea-borne pathogens, fleas were sampled from small mammals trapped in central Pennsylvania. A total of 541 small mammals were trapped, with white-footed mice (Peromyscus leucopus) and southern red-backed voles (Myodes gapperi) accounting for over 94% of the captures. Only P. leucopus were positive for examined blood-borne pathogens, with 47 (18.1%) and ten (4.8%) positive for Anaplasma phagocytophilum and Babesia microti, respectively. In addition, 61 fleas were collected from small mammals and tested for pathogens. Orchopeas leucopus was the most common flea and Bartonella vinsonii subspecies arupensis, B. microti, and a Rickettsia felis-like bacterium were detected in various flea samples. To the best of our knowledge, this is the first report of B. microti DNA detected from a flea and the first report of a R. felis-like bacterium from rodent fleas in eastern North America. This study provides evidence of emerging pathogens found in fleas, but further investigation is required to resolve the ecology of flea-borne disease transmission cycles.

Effective surveillance is essential for protecting livestock from Culicoides biting midges and the viruses they transmit. The objective of this study was to determine how the baiting system used in traps (UV, incandescent light, incandescent light with CO₂, and incandescent light with CO₂ and 1-octen-3-ol) influences estimates of midge population abundance, parity, and diel activity. This was achieved through a standardized trapping protocol conducted in three habitats in Sweden. UV light traps caught the most Culicoides species and more C. obsoletus complex females than incandescent light traps. Traps baited with CO₂ plus 1-octen-3-ol caught more female C. impunctatus than incandescent light traps. No consistent effect of bait type was found on C. obsoletus parity rate, as estimated from the proportion of midges with presence or absence of pigmentation. Midge activity, as reflected by trap catches, peaked between -3 h and +3 h relative to sunset, with UV traps catching significantly more female C. obsoletus complex and C. impunctatus at and after sunset than before sunset. We conclude that baiting system can influence biting midge collections, even using identical traps. Effective surveillance may require more than one bait type and kairomones to attract species that do not feed exclusively on cattle.

The Triatoma brasiliensis complex is composed of six species (Triatoma bahiensis, T. juazerensis, T. lenti, T. melanica, T. petrocchiae, and T. sherlocki) and two subspecies (T. brasiliensis brasiliensis and T. b. macromelasoma). Phylogenetic studies have shown that it is a monophyletic group, but the morphological relationships among the members can be better understood. We applied a tool of high resolution based on morphology to identify details that characterize the female genitals for each member of this group. The external genital structures of five to fifteen females of each taxon were analyzed. Insects had their abdomen transversely cut to separate the last abdominal segments, and representative illustrations obtained via scanning electron microscopy (SEM) are shown. Observations were performed in the dorsal and the ventral views. The morphological characterization of female external genitalia allowed a differentiation of each species/subspecies. The subspecies T. b. brasiliensis and T. b. macromelasoma were the most similar. On the other hand, dorsal view of structures evidenced some unique characteristics for T. petrocchiae and T. sherlocki. Regarding these structures for T. petrocchiae, the differentiation was in accordance with molecular studies, since this species exhibits the highest genetic distances in relation to other species of T. brasiliensis complex.

Invasive aquatic weeds are managed with herbicides to reduce their negative impacts on waterways in many areas, including the California Delta Region. Herbicides create a dynamic environment of living and decomposing plant matter that could affect larval mosquitoes and other invertebrates, such as their predators and competitors. Our objective was to compare the number of larval mosquitoes in water or water hyacinth, before and after an herbicide treatment. We created replicated pond mesocosms with water hyacinth, water hyacinth treated with glyphosate and an oil adjuvant, open water, and water with glyphosate plus adjuvant. We sampled for larval mosquitoes and other aquatic invertebrates. Before herbicide addition, there was a trend for more larval mosquitoes in open water tanks than in tanks with water hyacinth. Herbicide application resulted in an immediate decrease of larval mosquitoes. As decay progressed, larval mosquitoes became most abundant in mesocosms with herbicide-treated hyacinth and very few larval mosquitoes were found in other habitat treatments. Although the numbers of predatory and competitor insects had some variation between treatments, no clear pattern emerged. This information on how invasive weed management with herbicides affects larval mosquitoes will allow control practices for larval mosquitoes and invasive weeds to be better integrated.

Human health practitioners and wildlife biologists use insecticides to manage plague by suppressing fleas (Siphonaptera), but insecticides can also kill other ectoparasites. We investigated effects of deltamethrin and fipronil on ectoparasites from black-tailed prairie dogs (Cynomys ludovicianus, BTPDs). In late July, 2018, we treated three sites with 0.05% deltamethrin dust and 5 sites with host-fed 0.005% fipronil grain. Three non-treated sites functioned as experimental baselines. We collected ectoparasites before treatments (June-July, 2018) and after treatments (August-October, 2018, June-July, 2019). Both deltamethrin and fipronil suppressed fleas for at least 12 months. Deltamethrin had no detectable effect on mites (Arachnida). Fipronil suppressed mites for at least 12 months. Lice (Phthiraptera) were scarce on non-treated sites throughout the study, complicating interpretation. Concentrating on eight sites where all three ectoparasites where found in June-July, 2018 (before treatments), flea intensity was greatest on BTPDs carrying many lice and mites. These three ectoparasites co-occurred at high numbers, which might facilitate plague transmission in some cases. Lethal effects of insecticides on ectoparasite communities are potentially advantageous in the context of plague management.

The richness and abundance of sand fly species were studied in northeastern Brazil in areas of leishmaniasis transmission. The study was carried out in two forest areas with different deforestation times for agricultural and livestock activities: one modified by long-term settlement (more than 50 years of occupation) and another less impacted by short-term settlement (10 years). The sand flies were captured with CDC light traps from 18:00 to 06:00 for three consecutive nights, once a month, from May, 2012 to April, 2014. The study captured 21,708 specimens and also 33 species of Lutzomyia and two of Brumptomyia. Species richness and abundance were higher in the more conserved area of short-term occupation (31 species; 61.7%) than in the more degraded area with long-term occupation (17 species; 38.3%). In the most conserved area, the species richness was higher in the forest fragment than in the rural settlement, whereas in the degraded area the richness was higher in the peri-domicile than in the forest. The diversity was higher in the degraded area forest. There were significant statistical differences when comparing the means of total abundance with the intra-domicile, peri-domicile, and forest environments. The average abundance was statistically higher in the peri-domicile compared to the forest (p = 0.009), but there were no statistically significant differences between intra-domicile-peri-domicile (p = 0.11) and forest-intra-domicile (p = 0.87). In conclusion, a change in vegetation cover negatively affects the richness and abundance of sand flies in the natural environment.

Current methods of broad area application of contact insecticides used in mosquito control are becoming less effective, primarily due to resistance within mosquito populations. New methods that can deliver ingestible insecticides are being investigated as a means to mitigate resistance. This study evaluated insecticide delivery through toxic sugar baits (TSB) and resulting mortality of susceptible and resistant strains of Aedes aegypti. Two Ae. aegypti strains were evaluated using a 1% boric acid TSB: the susceptible Orlando 1952 (ORL) strain and the resistant Puerto Rican (PR) strain. The TSB resulted in high mortality for both ORL and PR strain of Ae. aegypti. Average mortality of female mosquitoes given TSB was 90.8% for PR and 99.3% for ORL. Our study suggests that targeting resistant mosquitoes with ingestible insecticides through TSBs could be a viable alternative to current mosquito control strategies and should be considered when developing an integrated vector management program.

Most data on species associations and vector potential of mosquitoes in relation to arboviral infections in South Africa date back from the 1940s to late 1990s. Contextual information crucial for disease risk management and control, such as the sampling effort, diversity, abundance, and distribution of mosquitoes in large parts of South Africa still remains limited. Adult mosquitoes were collected routinely from two horse farms in Gauteng Province; two wildlife reserves in Limpopo Province, at Orpen Gate in Kruger National Park (KNP) and Mnisi Area in Mpumalanga Province between 2014–2017, using carbon dioxide-baited light and tent traps. Mosquito diversity and richness are greater in untransformed natural and mixed rural settings. In untransformed wilderness areas, the most dominant species were Culex poicilipes, Anopheles coustani, and Aedes mcintoshi, while in mixed rural settings such as the Mnisi area, the two most abundant species were Cx. poicilipes and Mansonia uniformis. However, in peri-urban areas, Cx. theileri, Cx. univittatus, and Cx. pipiens sensu lato were the most dominant. Aedes aegypti, Ae. mcintoshi, Ae. metallicus, Ae. vittatus, Cx. pipiens s.l., Cx. theileri, and Cx. univittatus had the widest geographical distribution in northern South Africa. Also collected were Anopheles arabiensis and An. vaneedeni, both known malaria vectors in South Africa. Arbovirus surveillance and vector control programs should be augmented in mixed rural and peri-urban areas where the risk for mosquito-borne disease transmission to humans and domestic stock is greater.

The Northern Territory (NT) of Australia is currently free of the dengue mosquito Aedes (Stegomyia) aegypti (L). However, on 17 February 2004, two Ae. aegypti adults were captured in two routine CO₂-baited encephalitis virus surveillance traps in Tennant Creek, located 990 km south of Darwin in the NT. The detection triggered an immediate survey and control response undertaken by the NT Department of Health and Community Services, followed by a Commonwealth of Australia-funded Ae. aegypti elimination program. This report details the methods and results of the detection and subsequent elimination activities that were carried out between 2004 and 2006, returning the NT to its dengue vector-free status. There have been very few successful Ae. aegypti elimination programs in the world. This purposeful mosquito elimination for Australia was officially declared on 5 April 2006.

Biting midges are of interest to public health because they play an important role as vectors of disease-causing pathogens, as well as being a biting nuisance to humans and domestic animals. Although these insects are common in mangrove areas, they have not yet been studied in this ecosystem in the state of Maranhão (MA), Brazil. The objective of this study was to characterize the Culicoides community structure found in a mangrove swamp and verify if the use of vertebrate feces as bait interferes with their composition, richness, abundance, or seasonality. CDC light traps with vertebrate (chicken, ox, control, donkey, capuchin monkey and pig) feces baits were used to capture biting midges in a mangrove area of the Island of São Luís, MA. A total of 4,087 individuals representing 22 species of Culicoides were captured, the most abundant being C. (Oecacta) furens Poey (23.46%), C. (gr. Fluviatilis) leopoldoi Ortiz (21.58%), C. (Hoffmania) ignacioi Forattini (16.98%), C. (Hoffmania) maruim Lutz (13.85%), C. (Diphaomyia) iriartei Fox (10.57%), C. (Hoffmania) insignis Lutz (7.07%), and C. (gr. Limai) limai Barreto (3.03%). Species richness and abundance were higher when baits of capuchin monkey (15 species; 26.84% of the individuals) and pig (15; 25.3%) feces were used. The least attractive baits were donkey (12 species; 9.3%) and ox (nine species; 11.52%) feces. Biting midges were more abundant in the rainy season (67%), but richness was higher in the dry season (19 species). These results show that vertebrate feces may serve as olfactory cues and increase the attraction of biting midges to traps.

Improvement of morphological and molecular identification methods allows the detection of new species of mosquitoes. The mosquito fauna of Croatia currently includes 52 species, belonging to eight genera, including Anopheles (12 species), Aedes (24 species), Coquillettidia (one species), Culex (seven species), Culiseta (six species), Orthopodomyia (one species), and Uranotaenia (one species). This is an updated checklist, which includes five new species found in Croatian mosquito fauna. Two of these are invasive mosquito species, Aedes albopictus (Skuse, 1895) and Aedes japonicus (Theobald 1901), which are spreading across Europe and Croatia. The other three species, Culex laticinctus (Edwards 1913), Culex torrentium (Martini 1925), and Anopheles daciae (Linton, Nicolescu & Harbach 2004) are autochthonous species which haven't been recorded so far. Since there are several more invasive species spreading across Europe, we assume that this is not the final list.