Trap Catches Research Articles

Trap catches of Bactrocera species in selected urban sites in Bengaluru

Trap catches of Bactrocera species in selected urban sites in Bengaluru

A statistical calibration tool for methods used to sample outdoor-biting mosquitoes

BackgroundImproved methods for sampling outdoor-biting mosquitoes are urgently needed to improve surveillance of vector-borne diseases. Such tools could potentially replace the human landing catch (HLC), which, despite being the most direct option for measuring human exposures, raises significant ethical and logistical concerns. Several alternatives are under development, but detailed evaluation still requires common frameworks for calibration relative to HLC. The aim of this study was to develop and validate a statistical framework for predicting human-biting rates from different exposure-free alternatives.MethodsWe obtained mosquito abundance data (Anopheles arabiensis, Anopheles funestus and Culex spp.) from a year-long Tanzanian study comparing six outdoor traps [Suna Trap (SUN), BG Sentinel (BGS), M-Trap (MTR), M-Trap + CDC (MTRC), Ifakara Tent Trap-C (ITT-C) and Mosquito Magnet-X Trap (MMX)] and HLC. Generalised linear models were developed within a Bayesian framework to investigate associations between the traps and HLC, taking intra- and inter-specific density dependence into account. The best model was used to create a calibration tool for predicting HLC-equivalents.ResultsFor An. arabiensis, SUN catches had the strongest correlation with HLC (R2 = 19.4), followed by BGS (R2 = 17.2) and MTRC (R2 = 13.1) catches. The least correlated catch was MMX (R2 = 2.5). For An. funestus, BGS had the strongest correlation with the HLC (R2 = 53.4), followed by MTRC (R2 = 37.4) and MTR (R2 = 37.4). For Culex mosquitoes, the traps most highly correlated with the HLC were MTR (R2 = 45.4) and MTRC (R2 = 44.2). Density dependence, both between and within species, influenced the performance of only BGS traps. An interactive Shiny App calibration tool was developed for this and similar applications.ConclusionWe successfully developed a calibration tool to assess the performance of different traps for assessing outdoor-biting risk, and established a valuable framework for estimating human exposures based on the trap catches. The performance of candidate traps varied between mosquito taxa; thus, there was no single optimum. Although all the traps tested underestimated the HLC-derived exposures, it was possible to mathematically define their representativeness of the true biting risk, with or without density dependence. The results of this study emphasise the need to aim for a consistent and representative sampling approach, as opposed to simply seeking traps that catch the most mosquitoes.Graphical

A comparison of different Malaise trap types

Abstract Recent reports on insect decline have highlighted the need for long‐term data on insect communities towards identifying their trends and drivers. With the launch of many new insect monitoring schemes to investigate insect communities over large spatial and temporal scales, Malaise traps have become one of the most important tools due to the broad spectrum of species collected and reduced capture bias through passive sampling of insects day and night. However, Malaise traps can vary in size, shape, and colour, and it is unknown how these differences affect biomass, species richness, and composition of trap catch, making it difficult to compare results between studies. We compared five Malaise trap types (three variations of the Townes and two variations of the Bartak Malaise trap) to determine their effects on biomass and species richness as identified by metabarcoding. Insect biomass varied by 20%–55%, not strictly following trap size but varying with trap type. Total species richness was 20%–38% higher in the three Townes trap models compared to the Bartak traps. Bartak traps captured lower richness of highly mobile taxa but increased richness of ground‐dwelling taxa. The white roofed Townes trap captured a higher richness of pollinators. We find that biomass, total richness, and taxa group specific richness are all sensitive to Malaise trap type. Trap type should be carefully considered and aligned to match monitoring and research questions. Additionally, our estimates of trap type effects can be used to adjust results to facilitate comparisons across studies.

Host preference of bluetongue virus vectors, Culicoides species associated with livestock in West Bengal, India: Potential relevance on bluetongue epidemiology

Determination of host choice of Culicoides species (Diptera: Ceratopogonidae), the vectors of bluetongue virus (BTV), is pivotal to ascertain the role of each species in the transmission of pathogens, pest management and enumeration of disease prediction models. Host preference of livestock associated Culicoides midges was investigated in West Bengal, India with four replicates of a 3 × 3 Latin square design during August and September 2021. Adult Culicoides were mouth aspirated from three BTV hosts viz., cattle, sheep and goats. Mouth aspirating was validated by the sweep net collections. The host-baited collections recorded seven Culicoides species; with the highest landing rate on cattle (n = 5,667; 92.9%) followed by sheep (n = 365; 6.0%) and goat (n = 67; 1.1%). Based on the Jacob's selectivity index, all midge species, except for Culicoides fulvus Sen & Das Gupta, encountered, preferred cattle over other mammalian hosts. Culicoides oxystoma Kieffer, the subgenus Trithecoides Wirth & Hubert and Culicoides actoni Smith, predominated on the ventral region (belly/flank) of the cattle. However, Culicoides peregrinus Kieffer and C. actoni were observed to be prevalent in the leg region of sheep. A significantly higher percentage of female (99.9%) with only 0.3% of male were trapped in aspiration based animal baited collections. On the other hand sweep net and light trap catch comprises of 50.7%, 89.7% female and 49.2%, 10.2% male respectively. Surprisingly, DNA based blood meal analysis revealed human blood from the midges trapped in UV-LED light traps. Supplying the first evidence that Culicoides similis Carter, Ingram & Macfie, C. fulvus and Culicoides palpifer Das Gupta & Ghosh, feed on humans.

Population Dynamics of Insects and their Natural Enemies in Rice Ecosystem Assessed with Light Traps

The seasonal incidence of pests and their natural enemies in rice ecosystem was studied using yellow and white light traps during kharif 2019 in Annamalainagar. The trap catches were initiated from 34th Standard Meteorological Week (SMW) and the overall catches in the white light trap was the maximum in 36th SMW (113 adults) followed by 35th and 37th SMW. These declined in 44th SMW (36 adults). In yellow light trap, the peak catches were during 37th SMW (62 adults), while the least catch was during 43th week (23 adults). The natural enemies (predators and parasitoids) were noticed during 35th MSW (22 in both the light traps), which increased up to 40th SMW in white, and 39th week in yellow light traps, coinciding with the peak activity of pests. Correlation coefficients of trap catches revealed positive relationships with minimum temperature (0.644, 0.137), and sunshine hours (0.352, 0.214), whereas rainfall exhibited a negative one (-0.252, -0.048).

Automated Surveillance of Lepidopteran Pests with Smart Optoelectronic Sensor Traps

Several lepidopterans are pests in horticulture and pose biosecurity risks to trading countries worldwide. Efficient species-specific semiochemical lures are available for some of these pests, facilitating the implementation of surveillance programmes via trapping networks. These networks have a long history of success in detecting incursions of invasive species; however, their reliance on manual trap inspections makes these surveillance programmes expensive to run. Novel smart traps integrating sensor technology are being developed to detect insects automatically but are so far limited to expensive camera-based sensors or optoelectronic sensors for fast-moving insects. Here, we present the development of an optoelectronic sensor adapted to a delta-type trap to record the low wing-beat frequencies of Lepidoptera, and remotely send real-time digital detection via wireless communication. These new smart traps, combined with machine-learning algorithms, can further facilitate diagnostics via species identification through biometrics. Our laboratory and field trials have shown that moths flying in/out of the trap can be detected automatically before visual trap catch, thus improving early detection. The deployment of smart sensor traps for biosecurity will significantly reduce the cost of labour by directing trap visits to the locations of insect detection, thereby supporting a sustainable and low-carbon surveillance system.

Population Dynamics of Fall Army Worm <i>Spodoptera Frugiperda</i> (J E Smith) on Maize

Population dynamics of the fall army worm (FAW) Spodoptera frugiperdaon maize was carried out at the research field of Tamil Nadu Agricultural University, Coimbatore (kharif and rabi, 2018 and 2019). The results revealed that maximum FAW trap catches were obtained during 34th(7.6 moths/ trap) and 5th(7.8 moths/ trap) standard weeks (SW) of kharif and rabi seasons of 2018, respectively. During 2019, a more or less similar trend was observed with a maximum during 31st(7.2 moth/ trap) and 48th (8.2 moth/ trap) SW of kharif and rabi seasons, respectively. Correlation with weather factors indicated a significant negative correlation with evening relative humidity (RH) and significant positive correlation with morning RH during 2019-20. No significant effect of weather factors was observed during 2018-19 except for a significant positive correlation with evening RH and rainfall. The correlation between larval counts and pheromone trap catches were significantly positive with r-value of 0.55 and an R2value of 0.907 during 2018-19.

Contributions of CO2-Baited Malaise-Type Traps to the Knowledge of Hematophagous and Oestrid Flies (Diptera: Oestridae) Parasitizing Cervid Hosts.

This review describes an innovative and efficient modification of a type of Malaise trap meme overlooked in a recent review of such insect traps. It further identifies the large variety of dipteran parasites of vertebrates caught in the traps when CO2 was added as an attractant that otherwise rarely were caught in unbaited traps. Baited trap catches of parasitic flies mimicked those caught attacking cervid hosts. This review particularly focuses on comprehensive studies of: 1) several hematophagous species of largely unknown snipe flies (Diptera: Rhagionidae: Symphoromyia [Artiodactyla: Cervidae]) found host specific for Columbian black-tailed deer (Odocoileus hemionus columbianus Richardson), and 2) the biology of oestrid fly (Diptera: Oestridae) parasites of black-tailed deer and caribou/reindeer [Rangifer tarandus (L.) (Artiodactyla: Cervidae)], after it was discovered that the non-hematophagous females are guided to their vertebrate hosts by tracking a source of CO2, as done by many hematophagous flies.

Effects of insect net coverage in field vegetables on pests, diseases, natural enemies, and yield

With the reduced availability of effective plant protection products, alternative control measures gain importance. Insect net covers are a promising tool in this regard, because they can reduce pest damage on crop by exclusion of pests. However, as under practical conditions, most crop net covers need to be removed several times during a crop cycle to manage weeds and apply fertilizers, a complete exclusion of pests is not always feasible. In addition, net covers also have an impact on natural enemies, on microclimate, and may cause direct crop damage due to their tracking weight. Therefore, effects of net applications have to be assessed accordingly, depending on the specific crops and pests. In the current paper, effects on pests, on yield, and on the occurrence of diseases are assessed in Chinese cabbage, carrot, and leek. Whereas control of Delia radicum, Phyllotreta spp. and thrips was enhanced, aphids and mining flies showed increased population build ups and caused higher damages under net cover once they had been able to invade. Some plant diseases such as Puccinia spp. and Alternaria spp. did increase under the net covers. Pitfall trap catches in carrots and Chinese cabbage were lower in almost all natural enemy groups monitored under net covers as compared to open field plots. Yield was higher with net coverage in case of Chinese cabbage and leek, but not in carrot. Results are discussed and take into account the exclusion of natural enemies and measured changes in microclimate and photosynthetically active radiation.

Percentage of the bycatch and discard composition in artisanal bottom trap fisheries

Data on bycatch in the fishing effort required to manage fisheries resources. Unfortunately, the data on small-scale and traditional fisheries is still lacking. It makes it challenging to make fishing policies and regulations. Survey activities and experimental fishing were conducted to determine and analyze the composition of the main catch, bycatch and discarded by the local fisher's bottom traps in Sibolga, North Sumatra, Indonesia. Five units of the trap with a size of 150 cm x 100 cm x 50 cm (length x width x height) were used to collect fish data. These five trap units operated in the fishing ground, where local fishers usually operate their fishing gear. The fishing operation carried out within 1 mile of the coastline with water depths ranging from 7-10 meters. The duration of trap setting around 5-7 days for each fishing operation. A motorboat operated with a weight of 5.8 GT. The results showed that the total bottom trap catch consisted of 329 individuals with a total weight of 151.4 kg and 12 demersal fish species. The main catch was 148 individuals (88.9 kg), or 44.7% of the total catch during the experiment i.e. Chepalapholis urodeta, Ephinephelus areolatus, Epinephelus chlorostigma, Plectropomus leopardus, Ephinepelus coioides, Lates calcarifer, Lutjanus malabaricus, and Lutjanus erytropterus. The bycatch was 151 individuals (57.1 kg) or 46.1% i.e. Lethrinus obsoletus, Lutjanus ehrenbergii, Acanthurus auranticavus, Platax teira, Nemipterus japonicus, Scarus rivulatus, Lutjanus johnii, Siganus canaliculatus, Caesio cuning, and Taeniura lymma.While the discarded catch amounted to 30 individuals (5.4 kg) or 9.2% i.e. Naso brevirostris, Diodon holocanthus, and Diadema setosum. The bycatch utilization obtained by fishers was 83.4%, and the unutilized was 16.6%. The percentage of fish sizes worthy for consumption was 135 individuals (74.6%), and the size unworthy for consumption was 46 individuals (25.4%).Keywords:Fishing groundFishing gear Fishing operation Main catchTrap

Evaluation of insecticides and suitable trap containers for effective fruit fly catches

Fruit flies are quarantine pests and major impediments in horticultural production, domestic market, and export of fresh fruits and vegetables. Trapping with a lure is the best known method to monitor/ manage the fruit fly Bactrocera dorsalis populations. The fruit fly attraction and its mortality depend on the lure, type of killing agent, and design of the trap container. To make the trapping technology more robust, a study was conducted to find out the suitable killing agent amongst ten insecticides and the best trap design among the available six trap designs. The results revealed that emamectin benzoate 1.9EC was superior as killing agent with the maximum trap catches (648.75 to 1304.75 fruit flies/ trap) up to 12 weeks, followed by abamectin 1.9EC and profenophos 50EC. Among the trap designs, the CISH trap container was found to be superior (306.25 to 940.00 fruit flies/ trap/ week).

Sulcatol and Fuscumol Increase Catches of Leptostylus asperatus and Styloleptus biustus (Coleoptera: Cerambycidae) in Ethanol-Baited Traps

Sulcatol and Fuscumol Increase Catches of <i>Leptostylus asperatus</i> and <i>Styloleptus biustus</i> (Coleoptera: Cerambycidae) in Ethanol-Baited Traps

Shelter use by horses during summer in relation to weather conditions and horsefly (Tabanidae) prevalence

National legislation requires shelter access for horses kept outside during winter, whereas there are no requirements for shelter access to provide shade and a refuge from biting insects during summer. This study investigated use of artificial shelters by 10 horse groups continuously for eight summer weeks (2019: 5 groups, 2020: 5 groups, n = 42, 3 – 5 horses per group). Shelter use was recorded every 30 min, using wildlife cameras mounted inside the shelters, i.e., 48 recordings per day for 56 days (a total of 2688 recordings per group where each horse inside the shelter was identified and its behaviour noted). Daily weather conditions were recorded, and horsefly (Tabanidae) prevalence was quantified one day per week using H-traps (i.e. eight trap catches per group). The groups represented a variety of compositions (horse breed, age, gender) and shelter types (design, size). Across all groups and shelter types, shelter use increased on warmer days and the daily rhythm of shelter-seeking behaviour changed; on warmer days, shelter-seeking increased significantly during the day, whereas night-time use was unaffected. Further, significantly more horses were inside on days with the highest trap catch of horseflies compared to days with the lowest catch. We conclude that regardless of group composition and shelter type, horses make increased use of artificial shelters on warm summer days. Since all horses had access to natural shade in their pastures and shelter temperatures were generally higher than outdoor temperatures, we suggest that the increased shelter use on warm summer days was related to nuisance from biting insects. This is supported by the higher shelter use on days with a high horsefly catch. We recommend provision of shelter access to horses kept on summer pastures with limited opportunities to seek natural refuge from biting insects.

Cinnamyl alcohol: An attractant of the flower thrips Frankliniella intonsa

Catches of Frankliniella intonsa females (A) and males (B) in traps baited with five floral compounds (10 mg each) in red pepper fields • The flower thrips Frankliniella intonsa are attracted to highbush blueberry flowers. • Cinnamyl alcohol was the major component of floral volatiles of highbush blueberry. • Cinnamyl alcohol significantly attracted adult F. intonsa in the field. • The minor floral compounds had no additive activity with cinnamyl alcohol alone. Flower-inhabiting thrips find hosts using olfactory and visual cues. In this study, we report the identification of a plant-produced attractant of the flower thrips Frankliniella intonsa (Trybom), an important agricultural pest worldwide. GC–MS analysis of solid-phase microextraction samples from blueberry flowers, Vaccinium corymbosum L., that mediate the attraction of adult F. intonsa revealed that the major component was cinnamyl alcohol, followed by cinnamyl acetate, cinnamaldehyde, germacrene D, β -bourbonene, β -caryophyllene, and benzyl benzoate. The biological activity of the floral compounds was investigated using commercial cinnamaldehyde, cinnamyl alcohol, β -caryophyllene, cinnamyl acetate, and benzyl benzoate in hot pepper ( Capsicum annuum L.) fields. Significantly more F. intonsa males and females were caught in red delta traps with cinnamyl alcohol than in all other traps. Cinnamaldehyde and cinnamyl acetate attracted adult F. intonsa but were not as attractive as cinnamyl alcohol. β -Caryophyllene and benzyl benzoate were not attractive. Furthermore, the addition of four minor components to cinnamyl alcohol did not result in increased trap catches relative to cinnamyl alcohol alone, indicating that cinnamyl alcohol is responsible for attracting adult F. intonsa toward blueberry flowers. Therefore, this phenylpropanoid could be used as an effective lure for monitoring and controlling F. intonsa .

Evaluation of Selected Plant Volatiles as Attractants for the Stick Tea Thrip Dendrothrips minowai in the Laboratory and Tea Plantation.

Simple SummaryThe stick tea thrip Dendrothrips minowai is a key pest in tea plantations in China. In recent years, plant-derived semiochemicals have attracted considerable attention as promising attractants for the management of thrips, due to their safety and low cost. In this study, compounds that have been reported to attract other thrips or emitted from tea plants were evaluated for their electroantennogram (EAG), behavioral tests and field trapping efficacy for D. minowai. The EAG relative response value of D. minowai evoked by p-anisaldehyde, 3-methyl butanal, (E)-β-ocimene, farnesene, nonanal, eugenol, (+)-α-pinene, limonene, (−)-α-pinene, and γ-terpinene was significantly higher than the other compounds. Meanwhile, p-anisaldehyde, eugenol, farnesene, methyl benzoate, 3-methyl butanal, (E)-β-ocimene, (−)-α-pinene, (+)-α-pinene, and γ-terpinene led to attraction or repellency responses of female D. minowai. In addition, trap capture numbers of female D. minowai on sticky traps baited with p-anisaldehyde, eugenol, farnesene, and 3-methyl butanal were significantly higher than the control in tea plantations. Overall, our results highlight the potential application of plant volatiles in the development of effective, eco-friendly lure formulations for use in the monitoring and management of thrips.The stick tea thrip (Dendrothrips minowai Priesner) is the main pest thrip in tea (Camellia sinensis) plantations in China, and seriously affects the quality and yield of tea. Plant-derived semiochemicals provide an alternative to pheromones as lures and these compounds possess powerful attractiveness. In this study, we selected 20 non-pheromone semiochemicals, including compounds that have been reported to attract other thrips and some volatiles emitted from tea plants as the potential attractant components for D. minowai. In electroantennogram (EAG) assays, 10 synthetic compounds (p-anisaldehyde, 3-methyl butanal, (E)-β-ocimene, farnesene, nonanal, eugenol, (+)-α-pinene, limonene, (−)-α-pinene, and γ-terpinene) elicited significant antennal responses in female D. minowai. In addition, a two-choice H-tube olfactometer bioassay showed that D. minowai displayed significant positive responses to eight compound dilutions (p-anisaldehyde, eugenol, farnesene, methyl benzoate, 3-methyl butanal, (E)-β-ocimene, (−)-α-pinene, and (+)-α-pinene) when compared with the solvent control at both 1 and 2 h. Moreover, γ-terpinene exhibited a significantly deterrent effect on D. minowai. Finally, trap catches of four compounds (p-anisaldehyde, eugenol, farnesene, and 3-methyl butanal, respectively) significantly increase in tea plantations. Among these, the maximum number of D. minowai collected by blue sticky traps baited with p-anisaldehyde was 7.7 times higher than the control. In conclusion, p-anisaldehyde, eugenol, farnesene, and 3-methyl butanal could significantly attract D. minowai in the laboratory and under field conditions, suggesting considerable potential as commercial attractants to control D. minowai populations.

Development of Temporal Model for Forecasting of Helicoverpa armigera (Noctuidae: Lepidopetra) Using Arima and Artificial Neural Networks.

Helicoverpa armigera (Hübner) (Noctuidae: Lepidopetra) is a polyphagous pest of major crops grown in India. To prevent the damage caused by H. armigera farmers rely heavily on insecticides of diverse groups on a regular basis which is not a benign practice, environmentally and economically. To provide more efficient and accurate information on timely application of insecticides, this research was aimed to develop a forecast model to predict population dynamics of pod borer using Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Networks (ANN). The data used in this study were collected from the randomly installed sex pheromone traps at International Crops Research Institute for the Semi-arid Tropics (ICRISAT), Patancheru, Hyderabad. Several ARIMA (p, d, q) (P, D, Q) and ANN models were developed using the historical trap catch data. ARIMA model (1,0,1), (1,0,2) with minimal BIC, RMSE, MAPE, MAE, and MASE values and higher R2 value (0.53) was selected as the best ARIMA fit model, and neural network (7-30-1) was found to be the best fit to predict the catches of male moths of pod borer from September 2021 to August 2023. A comparative analysis performed between the ARIMA and ANN, shows that the ANN based on feed forward neural networks is best suited for effective pest prediction. With the developed ARIMA model, it would be easier to predict H. armigera adult population dynamics round the year and timely intervention of control measures can be followed by appropriate decision-making schedule for insecticide application.

Developing a mealybug pheromone monitoring tool to enhance IPM practices in New Zealand vineyards

Mealybugs are phloem-feeding insects found on many crops worldwide. In New Zealand vineyards, they transmit the economically important Grapevine leafroll-associated virus 3 (GLRaV-3). For some mealybug species, synthetic sex pheromones have been commercialised, and are used as monitoring tools. The mealybugs Pseudococcus longispinus and Pseudococcus calceolariae are major pests in many New Zealand vineyards. We present work on the development of a combined P. longispinus and P. calceolariae pheromone lure. The optimal dose for monitoring P. longispinus was found to be 10 µg of the (S)-(+)-enantiomer, either alone or in the racemic mixture. Addition of the corresponding alcohol did not improve trap catch of P. longispinus. Both the P. longispinus and the P. calceolariae pheromone lures remained active in the field for 90 days. Combining the 2 species’ pheromones had no negative effects on male mealybug trap catch for either species. We conclude that the pheromone ester alone is the best lure for the male P. longispinus. Combining the two mealybug species’ pheromones into a single lure provides the New Zealand viticultural industry with an efficient monitoring tool. Late-vintage deployment of baited lures will provide information on mealybug abundance and local distribution that will inform the scope of future insecticide programmes, to target areas based on need rather than an area-wide application by default.

Thermal sum requirements for development and flight initiation of new‐generation spruce bark beetles based on seasonal change in cuticular colour of trapped beetles

Abstract The spruce bark beetle Ips typographus is the most important pest on Norway spruce in Europe. To improve predictions of bark beetle phenology in a warmer climate, correct thermal sums representing the development time of the new generation are needed. A standardized method for classifying adults into five different colours was used for describing the seasonal change in colour of beetles in breeding substrate and in weekly trap catches from regions located in southern, central and northern Sweden in 2015–2020. Repeated sampling of I. typographus from breeding substrate demonstrated that the adults get gradually darker, from light brown when newly moulted to dark brown or black in the following summer. In spring, four to five colours co‐occurred among trapped beetles. Over time, the proportions of darker individuals increased until the two lightest colours were absent except for 2 cases out of 21 trapping locations/years. Thereafter, the individuals of the two lightest colours started to occur again, indicating that they belonged to the new generation. The average thermal sum from start of flight of parental generation in spring until onset of new‐generation flight in summer was higher for southern Sweden [lower developmental threshold (LDT) 5°C = 744 degree‐days (dd); LDT 8.3°C = 467 dd] than for northern Sweden (LDT 5°C = 668 dd; LDT 8.3°C = 418 dd). New‐generation flight occurred in every year and region, but generally constituted only a small proportion of total seasonal flight activity.

Beyond eves and cracks: An interdisciplinary study of socio-spatial variation in urban malaria transmission in Ethiopia.

During the past century, the global trend of reduced malaria transmission has been concurrent with increasing urbanization. Although urbanization has traditionally been considered beneficial for vector control, the adaptation of malaria vectors to urban environments has created concerns among scientific communities and national vector control programs. Since urbanization rates in Ethiopia are among the highest in the world, the Ethiopian government developed an initiative focused on building multi-storied units organized in condominium housing. This study aimed to develop an interdisciplinary methodological approach that integrates architecture, landscape urbanism, medical anthropology, and entomology to characterize exposure to malaria vectors in this form of housing in three condominiums in Jimma Town. Mosquitoes were collected using light trap catches (LTCs) both indoor and outdoor during 2019's rainy season. Architectural drawings and ethnographic research were superposed to entomological data to detect critical interactions between uses of the space and settlement conditions potentially affecting malaria vector abundance and distribution. A total of 34 anopheline mosquitoes comprising three species (Anopheles gambiae s.l, An. pharoensis and An. coustani complex) were collected during the three months of mosquito collection. Anopheles gambiae s.l, the principal malaria vector in Ethiopia, was the predominant species of all the anophelines collected. Distribution of mosquito breeding sites across scales (household, settlement, urban landscape) is explained by environmental conditions, socio-cultural practices involving modification of existing spaces, and systemic misfits between built environment and territory. Variations in mosquito abundance and distribution in this study were mainly related to standard building practices that ignore the original logics of the territory, deficiency of water and waste disposal management systems, and adaptations of the space to fit heterogeneous lifestyles of residents. Our results indicate that contextualizing malaria control strategies in relation to vector ecology, social dynamics determining specific uses of the space, as well as building and territorial conditions could strengthen current elimination efforts. Although individual housing remains a critical unit of research for vector control interventions, this study demonstrates the importance of studying housing settlements at communal level to capture systemic interactions impacting transmission at the household level and in outdoor areas.

Composition of mosquito fauna and insecticide resistance status of Anopheles gambiae sensu lato\xa0in Itang special district, Gambella, Southwestern Ethiopia

BackgroundAnopheles arabiensis, member species of the Anopheles gambiae complex, is the primary vector of malaria and is widely distributed in Ethiopia. Anopheles funestus, Anopheles pharoensis and Anopheles nili are secondary vectors occurring with limited distribution in the country. Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are pillars for the interventions against malaria control and elimination efforts in Ethiopia. However, the emergence and widespread of insecticide resistance in An. gambiae sensu lato (s.l.), might compromise the control efforts of the country. The aim of this study was to investigate composition of mosquito fauna and insecticide resistance status of An. gambiae s.l. in Itang special district ( woreda), Gambella, southwestern Ethiopia.MethodsAdult mosquitoes were sampled from September 2020 to February 2021 using the CDC light trap and pyrethrum spray catch (PSC). CDC light traps were placed in three selected houses for two consecutive days per month to collect mosquitoes indoor and outdoor from 6:00 P.M. to 06:00 A.M. and PSC was used to collect indoor resting mosquitoes from ten selected houses once in a month from October 2020 to February 2021. Moreover, mosquito larvae were also collected from different breeding sites and reared to adults to assess susceptibility status of populations of An. gambiae s.l. in the study area. Susceptibility tests were conducted on two to three days old non blood fed female An. gambiae s.l. using insecticide impregnated papers with deltamethrin (0.05%), alpha-cypermethrin (0.05%), propoxur (0.1%), pirimiphos-methyl (0.25%) and bendiocarb (0.1%) following World Health Organization (WHO) standard susceptibility test procedure. Molecular diagnostics were done for the identification of member species of An. gambiae s.l. and detection of knockdown resistance (kdr) allele using species specific polymerase chain reaction (PCR) and allele specific PCR.ResultsIn total, 468 adult mosquitoes were collected from different houses. Culex mosquitoes were the most dominant (80.4%) followed by Anopheles mosquitoes. Three species of Anopheles (Anopheles coustani, An. pharoensis, and An. gambiae s.l.) were identified, of which An. coustani was the dominant (8.1%) species. Higher number of mosquitoes (231) were collected outdoor by CDC light traps. Out of 468 adult mosquitoes, 294 were blood fed, 46 were half-gravid and gravid whereas the remaining 128 were unfed. WHO bioassay tests revealed that the populations of An. gambiae s.l. in the study area are resistant against alpha-cypermethrin and deltamethrin, but susceptible to bendiocarb, pirimiphos-methyl and propoxur. Of the total 86 An. gambiae s.l. specimens assayed, 79 (92%) successfully amplified and identified as An. arabiensis. West African kdr (L1014F) mutation was detected with high kdr allele frequency ranging from 67 to 88%.ConclusionThe detection of target site mutation, kdr L1014F allele, coupled with the phenotypic resistance against alpha-cypermethrin and deltamethrin call for continuous resistance monitoring.