1,319 research outputs found
Development and Testing of a Novel Automated Insect Capture Module for Sample Collection and Transfer
There exists an urgent need for efficient tools in disease surveillance to
help model and predict the spread of disease. The transmission of insect-borne
diseases poses a serious concern to public health officials and the medical and
research community at large. In the modeling of this spread, we face
bottlenecks in (1) the frequency at which we are able to sample insect vectors
in environments that are prone to propagating disease, (2) manual labor needed
to set up and retrieve surveillance devices like traps, and (3) the return time
in analyzing insect samples and determining if an infectious disease is
spreading in a region. To help address these bottlenecks, we present in this
paper the design, fabrication, and testing of a novel automated insect capture
module (ICM) or trap that aims to improve the rate of transferring samples
collected from the environment via aerial robots. The ICM features an
ultraviolet light attractant, passive capture mechanism, panels which can open
and close for access to insects, and a small onboard computer for automated
operation and data logging. At the same time, the ICM is designed to be
accessible; it is small-scale, lightweight and low-cost, and can be integrated
with commercially available aerial robots. Indoor and outdoor experimentation
validates ICM's feasibility in insect capturing and safe transportation. The
device can help bring us one step closer toward achieving fully autonomous and
scalable epidemiology by leveraging autonomous robots technology to aid the
medical and research community.Comment: Accepted to IEEE International Conference on Automation Science and
Engineering (CASE) 202
Designing Aedes mosquito traps: the evolution of the male Aedes sound trap by iterative evaluation insects
Effective surveillance of Aedes aegypti (Linnaeus, Diptera: Culicidae) is critical to monitoring the impact of vector control measures when mitigating disease transmission by this species. There are benefits to deploying male-specific traps, particularly when a high level of catch-specificity is desired. Here, the rationale behind the developmental process of an entirely new trap which uses a sound lure to capture male Ae. aegypti, the male Aedes sound trap (MAST), is presented as a target product profile with findings from developmental trials of key trap components and performance. Trial results suggest that the presence of a black base associated with the trap influenced male catches as did variations in size of this base, to a degree. Trap entrance shape didnât influence catch rates, but entrance size did. No significant differences in catch rates were found when sound lures were set to intermittent or continuous playbacks, at volumes between 63â74 dB or frequencies of 450 Hz compared to 500 Hz. Additionally, adult males aged 3 days post-eclosion, were less responsive to sound lures set to 500 Hz than those 4 or 6 days old. Lastly, almost no males were caught when the MAST directly faced continual winds of 1.5 msâ1, but males were captured at low rates during intermittent winds, or if the trap faced away from the wind. The developmental process to optimising this trap is applicable to the development of alternate mosquito traps beyond Aedes sound traps and provides useful information towards the improved surveillance of these disease vectors
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Behavioural and chemical ecology of <i>Meligethes aeneus</i>: effects of non-host plant volatiles
The research in this thesis aims to develop an understanding of the olfactory aspects of host-location behaviour in the pest beetle Meligethes aeneus Fab., and to investigate the use of non-host plant volatiles as ârepellentsâ within a push-pull system of pest control for oilseed rape, which is being developed at Rothamsted Research.
Novel laboratory bioassays were developed and used to establish that essential oils from non-host plants reduce M. aeneus colonisation of oilseed rape flowers. Lavender essential oil had the greatest negative effect on beetle numbers on rapeseed flowers. This was further examined using a 4-arm olfactometer, and it was established that lavender oil alone elicits avoidance behaviours in M. aeneus, in addition to overriding their attraction to host-plant volatiles. The chemical basis of this effect was investigated using gas chromatography linked with electroantennography and mass spectrometry and the results are discussed in relation to the ecology of the insect.
It was established with semi-field studies that lavender essential oil reduces landing of M. aeneus, but does not affect the post-alighting behavioural process of host acceptance. These results are discussed in terms of behavioural plasticity in the importance of olfactory cues for host location such that, on alighting on a plant, the beetle may switch behavioural modes or may require a different suite of olfactory cues during host-acceptance behaviour. Field studies showed that lavender oil is effective at reducing natural movements of M. aeneus into plots of oilseed rape. Critically, the main reduction in infestation occurred during the vulnerable green-bud stage and the implications for optimal timing of repellent application during immigration are discussed. Flight patterns were further investigated using a novel combination of vertical-looking radar, suction traps and field counts to identify important meteorological and ecological factors.
The thesis presents an experimental progression in scale from the laboratory, to semi-field and field scale, for research into the effect of semiochemicals. The application and efficacy of using lavender or other non-host plant odours within a push-pull system of pest management for M. aeneus in oilseed rape are discussed
Evaluation of candidate pheromone blends for mating disruption of the invasive swede midge (Contarinia nasturtii)
Swede midge (Contarinia nasturtii, Diptera: Cecidomyiidae) is a small invasive fly that is currently threatening Brassica vegetable and oilseed production in the Northeastern U.S. and Canada. Larvae feed on plant meristems, resulting in deformed leaves, stems, and heads. Extremely low damage thresholds for heading Brassica vegetables, multiple overlapping generations, and lack of effective organic insecticide options present serious challenges for managing this pest. Pheromone mating disruption (PMD), which involves confusing male insects with unnaturally large doses of sex pheromones, is particularly promising for swede midge management because it prevents mating and subsequent oviposition. One major challenge to PMD for swede midge management is that the chiral female pheromone blend, a 1:2:0.02 blend of (2S, 9S)-diacetoxyundecane, (2S, 10S)-diacetoxyundecane and (S)-2-acetoxyundecane, is expensive to synthesize due to the structural complexity of the compounds. Here, we explored three ways to reduce the cost of swede midge PMD: the use of lower-cost racemic pheromones containing all possible stereoisomers, single-component blends, and the possibility of using timed pheromone dispensers by testing for diel patterns of midge reproductive behavior.
Although we found that males were not attracted to blends containing the racemic stereoisomers of the main pheromone component, (2S, 10S)-diacetoxyundecane, racemic blends functioned equally as well as chiral blends in confusing males and altering female behavior in PMD systems. We observed 95% and 87% reductions in males caught in monitoring traps in three-component chiral and racemic PMD plots of broccoli, respectively. In addition to confusing males, we also found that females altered their reproductive behavior in response to both chiral and racemic pheromones. Females released pheromones more frequently when exposed to three-component chiral and racemic blends, and were less likely to mate afterward. Single-pheromone treatments containing either chiral or racemic 2,10-diacetoxyundecane neither confused males nor influenced female behavior.
We identified a total of eight hours during the day and night when midges do not exhibit mate-seeking behavior, during which programmable PMD dispensers could be turned off to save pheromone inputs. We found that up to 81% of females released pheromones to attract males for mating in the early morning shortly after dawn. Most females emerged in the morning as well, releasing pheromones soon after eclosing. Because midges are receptive to mates shortly after emergence, they may mate at their emergence site.
Overall, we found relatively high levels of crop damage in our pheromone-treated plots, likely due to the migration of mated females into our plots. If midges mate at emergence sites, rotation of Brassica vegetable crops may result in overwintered midges emerging in fields where host plants are not currently grown. Further research is needed to determine where midges mate in order to determine where to install PMD dispensers
Host plant finding by Acraea acerata Hew. (Lepidoptera: Nymphalidae), the sweet potato butterfly: implications for pest management
Phytophagous insects such as Lepidopteran species utilise both olfactory and visual cues to locate their host-plants used as mating or oviposition sites, shelter or food. Larvae of Acraea aceratafeed on sweet potato plant leaves causing more that 50 % loss of sweet potato tuber yield in some East African countries. Attempting to elaborate a management strategy to control A. aceratasuitable to a tropical resource- poor farming system, it was essential to investigate how the butterfly finds its host- plants. The results of a wind tunnel bioassay using glass-screened, muslin-screened and non-screened sweet potato plants suggested that sweet potato plant volatiles play an important role in attracting A. aceratato its host-plant. This was supported by both the distance moved by female A. aceratatowards muslin-screened plants (olfactory cues) and the percentage of butterflies which landed on the screen. Visual stimuli seemed to have a negative effect. The attractiveness of sweet potato plant volatiles to A. aceratawas later confirmed by the use of volatiles collected by headspace entrainment from sweet potato plantsThe main components of sweet potato plant volatiles were tentatively identified by GC-MS (Gas Chromatography coupled with Mass Spectrometry) analysis and electrophysiological responses were recorded for some of them. Compared to ethylbenzene, 3-carene and (-) trans-caryophyllene, 3-hexen-l-ol,(Z), a general green leaf alcohol, elicited far more substantial EAG (electroantennogram) responses in A.acerata.This result suggested that A. aceratamight well respond to a specific blend of volatiles made up of the different chemical components of sweet potato plant volatiles instead of one or two specific chemical components.Considering the important role of sweet potato plant volatiles in attracting A. acerata,a number of plants reported to be repellent to herbivorous insects were mixed with sweet potato plants and screened for repelling/disorienting of female A. aceratain olfactometer and wind tunnel bioassays. Two plant mixtures with opposite effects on the response of A. aceratato their volatiles were identified: sweet potato + Desmodiumplant volatiles were found to be more attractive to the butterfly than sweet potato plant volatiles alone, and sweet potato + onion plant volatiles which reduced considerably the attractiveness of sweet potato plant volatiles to A. acerata.As the trichomes of Desmodiumplants were reported to trap insects, a âpush-pullâ management strategy for A. aceratainvolving the two intercrops was suggested: the intercrop sweet potato + onion plants would âpushâ away ovipositing A. aceratawhereas the intercrop sweet potato + Desmodiumplants would attract the butterflies which would be trapped by Desmodiumtrichomes. The results of a preliminary field experiment carried out in Uganda suggested that the intercrop sweet potato + onion plants had a negative effect on the number of egg batches laid by A. acerataon sweet potato plants. There is, therefore, a need for comprehensive field experimentation of the whole strategy to validate these laboratory and field experimental findings
Adaptive path planning for fusing rapidly exploring random trees and deep reinforcement learning in an agriculture dynamic environment UAVs
Unmanned aerial vehicles (UAV) are a suitable solution for monitoring growing cultures due to the possibility of covering a large area and the necessity of periodic monitoring. In inspection and monitoring tasks, the UAV must find an optimal or near-optimal collision-free route given initial and target positions. In this sense, path-planning strategies are crucial, especially online path planning that can represent the robotâs operational environment or for control purposes. Therefore, this paper proposes an online adaptive path-planning solution based on the fusion of rapidly exploring random trees (RRT) and deep reinforcement learning (DRL) algorithms applied to the generation and control of the UAV autonomous trajectory during an olive-growing fly traps inspection task. The main objective of this proposal is to provide a reliable route for the UAV to reach the inspection points in the tree space to capture an image of the trap autonomously, avoiding possible obstacles present in the environment. The proposed framework was tested in a simulated environment using Gazebo and ROS. The results showed that the proposed solution accomplished the trial for environments up to 300 m3 and with 10 dynamic objects.The authors would like to thank the following Brazilian Agencies CEFET-RJ, CAPES, CNPq, and FAPERJ. The authors also want to thank the Research Centre in Digitalization and Intelligent Robotics (CeDRI), Instituto PolitĂ©cnico de BragançaâIPB (UIDB/05757/2020 and UIDP/05757/2020), the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI, and LaboratĂłrio Associado para a Sustentabilidade e Tecnologia em RegiĂ”es de Montanha (SusTEC) and IPB, Portugal. This work was carried out under the Project âOleaChain: CompetĂȘncias para a sustentabilidade e inovação da cadeia de valor do olival tradicional no Norte Interior de Portugalâ (NORTE-06-3559-FSE-000188), an operation to hire highly qualified human resources, funded by NORTE 2020 through the European Social Fund (ESF).info:eu-repo/semantics/publishedVersio
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