Specificity of the Receptor for the Major Sex Pheromone Component in Heliothis virescens

In a previous study, the Drosophila melanogaster OR67d(GAL4);UAS system was used to functionally characterize the receptor for the major component of the sex pheromone in the tobacco budworm, Heliothis virescens Fabricius (Lepidoptera: Noctuidae), HvOR13. Electrophysiological and behavioral assays showed that transgenic flies expressing HvOR13 responded to (Z)-11-hexadecenal (Z11-16:Ald). However, tests were not performed to determine whether these flies would also respond to secondary components of the H. virescens sex pheromone. Thus, in this study the response spectrum of HvOR13 expressed in this system was examined by performing single cell recordings from odor receptor neuron in trichoid T1 sensilla on antennae of two Or67d(GAL4 [1]); UAS-HvOR13 lines stimulated with Z11-16:Ald and six H. virescens secondary pheromone components. Fly courtship assays were also performed to examine the behavioral response of the Or67d(GAL4[1]); UAS-HvOR13 flies to Z11-16:Ald and the secondary component Z9-14:Ald. Our combined electrophysiological and behavioral studies indicated high specificity and sensitivity of HvOR13 to Z11-16:Ald. Interestingly, a mutation leading to truncation in the HvOR13 C-terminal region affected but did not abolish pheromone receptor response to Z11-16:Ald. The findings are assessed in relationship to other HvOR13 heterologous expression studies, and the role of the C-terminal domain in receptor function is discussed. A third line expressing HvOR15 was also tested but did not respond to any of the seven pheromone components

A critical assessment of the detailed Aedes aegypti simulation model Skeeter Buster 2 using field experiments of indoor insecticidal control in Iquitos, Peru

The importance of mosquitoes in human pathogen transmission has motivated major research efforts into mosquito biology in pursuit of more effective vector control measures. Aedes aegypti is a particular concern in tropical urban areas, where it is the primary vector of numerous flaviviruses, including the yellow fever, Zika, and dengue viruses. With an anthropophilic habit, Ae. aegypti prefers houses, human blood meals, and ovipositioning in water-filled containers. We hypothesized that this relatively simple ecological niche should allow us to predict the impacts of insecticidal control measures on mosquito populations. To do this, we use Skeeter Buster 2 (SB2), a stochastic, spatially explicit, mechanistic model of Ae. aegypti population biology. SB2 builds on Skeeter Buster, which reproduced equilibrium dynamics of Ae. aegypti in Iquitos, Peru. Our goal was to validate SB2 by predicting the response of mosquito populations to perturbations by indoor insecticidal spraying and widespread destructive insect surveys. To evaluate SB2, we conducted two field experiments in Iquitos, Peru: a smaller pilot study in 2013 (S-2013) followed by a larger experiment in 2014 (L-2014). Here, we compare model predictions with (previously reported) empirical results from these experiments. In both simulated and empirical populations, repeated spraying yielded substantial yet temporary reductions in adult densities. The proportional effects of spraying were broadly comparable between simulated and empirical results, but we found noteworthy differences. In particular, SB2 consistently over-estimated the proportion of nulliparous females and the proportion of containers holding immature mosquitoes. We also observed less temporal variation in simulated surveys of adult abundance relative to corresponding empirical observations. Our results indicate the presence of ecological heterogeneities or sampling processes not effectively represented by SB2. Although additional empirical research could further improve the accuracy and precision of SB2, our results underscore the importance of non-linear dynamics in the response of Ae. aegypti populations to perturbations, and suggest general limits to the fine-grained predictability of its population dynamics over space and time

Evaluation of "Caserotek" a low cost and effective artificial blood-feeding device for mosquitoes.

Entomological research studies on mosquito vector biology, vector competence, insecticide resistance, dispersal, and survival (using mark-release-recapture techniques) often rely on laboratory-reared mosquito colonies to produce large numbers of consistently reared, aged, and sized mosquitoes. We developed a low-cost blood feeding apparatus that supports temperatures consistent with warm blooded animals, using commonly available materials found in low resource environments. We compare our system ("Caserotek") to Hemotek and glass/membrane feeding methods. Two experiments were conducted with Aedes aegypti (Linnaeus 1762) and one with Anopheles darlingi (Root 1926) (Diptera: Culicidae); 3 replicates were conducted for each experiment. Aedes aegypti female mosquitoes were provided chicken blood once per week for 30 min (Experiment #1) for 14 days or 1 hour (Experiment #2) for 21 days. Anopheles darlingi were fed once for 1 hour (Experiment #3). Blood-feeding rates, survival rates, and egg production were calculated across replicates. Caserotek had a significantly higher 30-min engorgement rate (91.1%) than Hemotek (47.7%), and the glass feeder (29.3%) whereas for 1-hour feeding, Hemotek had a significantly lower engorgement rate than either of the other two devices (78% versus 91%). Thirty-day survival was similar among the feeding devices, ranging from 86% to 99%. Mean egg production was highest for the Caserotek feeder (32 eggs per female) compared to the glass feeder and Hemotek device (21-22 eggs per female). Our new artificial feeding system had significantly higher blood feeding rates than for more expensive artificial systems and was equivalent to other fitness parameters. Caserotek only requires the ability to boil water to maintain blood temperatures using a Styrofoam liner. It can be easily scaled up to large production facilities and used under austere conditions

Evaluation of “Caserotek” a low cost and effective artificial blood-feeding device for mosquitoes

Entomological research studies on mosquito vector biology, vector competence, insecticide resistance, dispersal, and survival (using mark-release-recapture techniques) often rely on laboratory-reared mosquito colonies to produce large numbers of consistently reared, aged, and sized mosquitoes. We developed a low-cost blood feeding apparatus that supports temperatures consistent with warm blooded animals, using commonly available materials found in low resource environments. We compare our system ("Caserotek") to Hemotek and glass/membrane feeding methods. Two experiments were conducted with Aedes aegypti (Linnaeus 1762) and one with Anopheles darlingi (Root 1926) (Diptera: Culicidae); 3 replicates were conducted for each experiment. Aedes aegypti female mosquitoes were provided chicken blood once per week for 30 min (Experiment #1) for 14 days or 1 hour (Experiment #2) for 21 days. Anopheles darlingi were fed once for 1 hour (Experiment #3). Blood-feeding rates, survival rates, and egg production were calculated across replicates. Caserotek had a significantly higher 30-min engorgement rate (91.1%) than Hemotek (47.7%), and the glass feeder (29.3%) whereas for 1-hour feeding, Hemotek had a significantly lower engorgement rate than either of the other two devices (78% versus 91%). Thirty-day survival was similar among the feeding devices, ranging from 86% to 99%. Mean egg production was highest for the Caserotek feeder (32 eggs per female) compared to the glass feeder and Hemotek device (21-22 eggs per female). Our new artificial feeding system had significantly higher blood feeding rates than for more expensive artificial systems and was equivalent to other fitness parameters. Caserotek only requires the ability to boil water to maintain blood temperatures using a Styrofoam liner. It can be easily scaled up to large production facilities and used under austere conditions

Field Evaluation of Novel Spatial Repellent Controlled Release Devices (CRDs) against Mosquitoes in an Outdoor Setting in the Northern Peruvian Amazon

U.S. military troops are exposed to mosquito-borne pathogens when deployed to endemic regions. Personal protective measures such as permethrin-treated uniforms and dermal repellents are the cornerstones of mosquito-borne disease prevention for the U.S. military. These measures have limitations and additional personal protection tools, such as spatial repellent devices to decrease the risk of vector-borne pathogen transmission, are required. Novel spatial repellent controlled-release devices formulated with metofluthrin were evaluated in an outdoor setting in the northern Amazon of Peru to evaluate performance under field conditions. The metofluthrin emitting devices lowered the number of mosquitoes captured in protected human landing collections (HLC) compared to blank devices, although there were effect differences between Anopheles spp. and species in other mosquito genera. A computational-experimental model was developed to correlate HLC and active ingredient (AI) concentrations as a function of time and space. Results show a strong correlation between the released AI and the decrease in HLC. This model represents the first effort to obtain a predictive analytical tool on device performance using HLC as the entomological endpoint

Distribution and identification of sand flies naturally infected with <i>Leishmania</i> from the Southeastern Peruvian Amazon

<div><p>Background</p><p>Cutaneous leishmaniasis (CL) is an important health problem in the New World affecting civilian and military populations that are frequently exposed in endemic settings. The Peruvian region of Madre de Dios located near the border with Brazil is one of the most endemic CL regions in South America with more than 4,451 reported cases between 2010 and 2015 according to the Peruvian epidemiology directorate. However, little is known regarding the diversity and distribution of sand fly vectors in this region. In this study, we aimed to characterize the sand fly fauna in this endemic setting and identify sand fly species naturally infected with <i>Leishmania</i> possibly involved in pathogen transmission.</p><p>Methods</p><p>Sand fly collections were carried out during 2014 and 2015 in the communities of Flor de Acre, Villa Primavera, Mavila and Arca Pacahuara using CDC light traps and Shannon traps. Collected specimens were identified and non-blood-fed females were selected for <i>Leishmania</i> infection screening using kinetoplastid DNA-PCR (kDNA-PCR) and nested Real time PCR for species identification.</p><p>Results</p><p>A total of 10,897 phlebotomines belonging to the genus <i>Lutzomyia</i> (58 species) and <i>Brumptomyia</i> (2 species) were collected. Our study confirmed the widespread distribution and abundance of <i>Lutzomyia (Trichophoromyia) spp</i>. (24%), <i>Lu</i>. <i>whitmani</i> (19.4%) and <i>Lu</i>. <i>yucumensis</i> (15.8%) in the region. Analysis of Shannon diversity index indicates variability in sand fly composition across sites with Villa Primavera presenting the highest sand fly diversity and abundance. <i>Leishmania</i> screening by kDNA-PCR resulted in 45 positive pools collected from Flor de Acre (34 pools), Mavila (10 pools) and Arca Pacahuara (1 pool) and included 14 species: <i>Lu</i>. <i>yucumensis</i>, <i>Lu</i>. <i>aragoi</i>, <i>Lu</i>. <i>sallesi</i>, <i>Lu</i>. <i>sherlocki</i>, <i>Lu</i>. <i>shawi</i>, <i>Lu</i>. <i>walkeri</i>, <i>Lu nevesi</i>, <i>Lu</i>. <i>migonei</i>, <i>Lu</i>. <i>davisi</i>, <i>Lu</i>. <i>carrerai</i>, <i>Lu</i>. <i>hirsuta</i>, <i>Lu</i>. <i>(Trichophoromyia) spp</i>., <i>Lu</i>. <i>llanosmartinsi</i> and <i>Lu</i>. <i>whitmani</i>. <i>Lutzomyia sherlocki</i>, <i>Lu</i>. <i>walkeri</i> and <i>Lu</i>. <i>llanosmartinsi</i> had the highest infection rates (8%, 7% and 6%, respectively). We identified <i>Leishmania guyanensis</i> in two <i>Lu</i>. <i>whitmani</i> pools, and <i>L</i>. <i>braziliensis</i> in two <i>Lu</i>. <i>llanosmartinsi</i> pools and one <i>Lu</i>. <i>davisi</i> pool.</p><p>Conclusions</p><p>Based on our collections there is high sand fly diversity in Madre de Dios, with differences in sand fly abundance and species composition across sites. We identified 14 sand fly species naturally infected with <i>Leishmania</i> spp., having detected natural infection with <i>L</i>. (<i>V</i>.) <i>guyanensis</i> and <i>L</i>. (<i>V</i>.) <i>braziliensis</i> in three sand fly species. These results suggest the presence of several potential vectors that vary in their spatial and geographical distribution, which could explain the high prevalence of CL cases in this region.</p></div

<i>Spodoptera frugiperda</i> male trapping experiments conducted in North America, the Caribbean and South America.

1<p>Experiments: A) Test of two 4-component blends (Blend 1 and Blend 2), B) Z7-12:OAc dose-response, C) Z11-16:OAc dose-response, D) Importance of E7-12:OAc.</p>2<p>Data adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089255#pone.0089255-Unbehend1" target="_blank">[52]</a>.</p

Attraction of corn-strain (A) and rice-strain (B) males to different doses of Z7-12:OAc.

<p>Bars represent the mean percentage of males caught per trap (0%, 2%, 4%, or 10% Z7-12:OAc +100% Z9-14:OAc) and per biological replicate (n = 3). Different letters above the bars indicate significant differences. Error bars show the variation between biological replicates (n = 3). Numbers in brackets/bars represent the total number of males caught. Data from Florida are adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089255#pone.0089255-Unbehend1" target="_blank">[52]</a>.</p

Attraction of <i>Spodoptera frugiperda</i> corn- and rice-strain males to two 4-component blends in different regions.

<p>Bars show the mean percentage of males caught per trap (Blend 1∶100% Z9-14:OAc +13% Z11-16:OAc +2% Z7-12:OAc +1% Z9-12:OAc; Blend 2∶100% Z9-14:OAc +8% Z11-16:OAc +4% Z7-12:OAc +2% Z9-12:OAc) and per biological replicate. There were three biological replicates per field (n = 3), except for all fields in North Carolina (n = 1) and for rice-strain males in Peru (n = 1), where only one replicate caught males. The standard errors in all fields in North Carolina show the variation between rotations in one replicate (n = 3), while all other error bars show the variation between biological replicates (n = 3). Numbers in brackets/bars represent the total number of males caught,* = <i>P</i><0.05,** = <i>P</i><0.01, n.s. = not significant. Data from Florida are adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089255#pone.0089255-Unbehend1" target="_blank">[52]</a>.</p

Test statistics on the <i>Spodoptera frugiperda</i> male trap catches of different experiments.

<p>Experiments A (Test of two 4-component blends: Blend 1 and Blend 2) and B (Z7-12:OAc dose-response experiment) were analyzed individually using square root transformed data in a MANOVA and a Wilks’ Lambda test. Bold P-values show a significant effect of geographic region, strain-identity of males, and/or the field crop, influencing the attraction of fall armyworm males to synthetic pheromone blends. Mean values and standard errors are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089255#pone-0089255-g001" target="_blank">Figure 1</a> (Exp. A) and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0089255#pone-0089255-g002" target="_blank">Figure 2</a> (Exp. B).</p