Dispersion pattern of Mansonia in the surroundings of the Amazon Jirau Hydroelectric Power Plant

Mansonia spp. are voracious hematophagous mosquitoes whose mature stages usually breed in freshwater bodies containing aquatic vegetation. The reduction in water flow leads to a proliferation in aquatic plants, increasing their populations. Besides, some species are potential vectors of pathogens such as arboviruses and microfilariae. We evaluated the degree of active dispersion of females of Mansonia spp. in the surrounding area of the Jirau hydroelectric power plant in the Amazon, Rondônia, Brazil, using mark-release-recapture techniques. The flight behavior of the recaptured specimens was summarized with a set of average and maximum distances traveled. We show that the dispersal movement of Mansonia spp. is predominantly performed by random, low, and short flights, with a tendency to remain near the breeding sites in certain vegetation fragments. However, the maximum distances traveled were 2000 m from the release point for Mansonia amazonensis during 2018 and Mansonia humeralis during 2019.

Variations of Movement, Dispersal, and Morphometrics among Subpopulations of Javan Endemic Damselfly, Drepanosticta spatulifera (Odonata: Platystictidae) in Petungkriyono Forest

Drepanosticta spatulifera is a Javan endemic damselfly. The population is spread unevenly in the Petungkriyono Forest and is threatened due to environmental pressure. The aims of this research are to know the variation of the movement, dispersal, and morphometric among subpopulations of D. spatulifera. Movement and dispersal variation data collection was done using Mark Release Recapture (MRR) for six weeks from early August until mid-September 2020. The collection of morphometric samples was done during the last week of the MRR survey and 46 individuals were measured with 12 continuous characters. During the MRR survey, 596 males of D. spatulifera were marked and 302 were recaptured. D. spatulifera had short movement and dispersal thus no individuals were found across the subpopulations. The distance moved of successive capture and net lifetime movement were dominantly less or equal to five meters. The duration of the MRRsurvey had a low correlation with the dispersal distance of D. spatulifera. In themorphometric variations, closer subpopulations tended to have a similar cluster ofmorphometric characters. Variation of distance moved between successive captureand wing size from Mangli Stream was significantly different from other sites. Thesubpopulation of Mangli, the farthest and higher altitude of the sites, had thehighest distance move, more disperse, and the largest wing size. Our study showedthat D. spatulifera was extremely sedentary damselfly. It will enhance inbreeding andvulnerability to extinction. Therefore, the interaction between the subpopulationsof D. spatulifera in the Petungkriyono Forest needs to be done more.

Mark-release-recapture of male Aedes aegypti (Diptera: Culicidae): Use of rhodamine B to estimate movement, mating and population parameters in preparation for an incompatible male program

Rapid advances in biological and digital support systems are revolutionizing the population control of invasive disease vectors such as Aedes aegypti. Methods such as the sterile and incompatible insect techniques (SIT/IIT) rely on modified males to seek out and successfully mate with females, and in doing so outcompete the wild male population for mates. Currently, these interventions most frequently infer mating success through area-wide population surveillance and estimates of mating competitiveness are rare. Furthermore, little is known about male Ae. aegypti behaviour and biology in field settings. In preparation for a large, community scale IIT program, we undertook a series of mark- release-recapture experiments using rhodamine B to mark male Ae. aegypti sperm and measure mating interactions with females. We also developed a Spatial and Temporally Evolving Isotropic Kernel (STEIK) framework to assist researchers to estimate the movement of individuals through space and time. Results showed that ~40% of wild females captured daily were unmated, suggesting interventions will need to release males multiple times per week to be effective at suppressing Ae. aegypti populations. Males moved rapidly through the landscape, particularly when released during the night. Although males moved further than what is typically observed in females of the species, survival was considerably lower. These unique insights improve our understanding of mating interactions in wild Ae. aegypti populations and lay the foundation for robust suppression strategies in the future.

Eave and swarm collections prove effective for biased captures of male Anopheles gambiae mosquitoes in Uganda

Background Traditional malaria vector sampling techniques bias collections towards female mosquitoes. Comprehensive understanding of vector dynamics requires balanced vector sampling of both males and females. Male mosquito sampling is also necessary for population size estimations by male-based mark-release-recapture (MRR) studies and for developing innovations in mosquito control, such as the male-targeted sterile insect technique and other genetic modification approaches. This study evaluated a range of collection methods which show promise in providing a more equal, or even male-biased, sex representation in the sample. Results Swarms were found at all study sites and were more abundant and larger at the peak of the wet season. Swarm sampling caught the most males, but when man/hour effort was factored in, sampling of eaves by aspiration was the more efficient method and also provided a representative sample of females. Grass-roofed houses were the most productive for eave collections. Overall few mosquitoes were caught with artificial resting traps (clay pots and buckets), although these sampling methods performed better at the start of the wet season than at its peak, possibly because of changes in mosquito ecology and an increased availability of natural resting sites later in the season. Aspiration of bushes was more productive at the peak of the wet season than at the start. Conclusions The results of this study demonstrate that eave aspiration was an efficient and useful male mosquito collection method at the study sites and a potentially powerful aid for swarm location and MRR studies. The methods evaluated may together deliver more sex-balanced mosquito captures and can be used in various combinations depending on the aims and ecological parameters of a given study.

Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes

Background Anopheles arabiensis is a major malaria vector, recently implicated as contributing to ongoing residual malaria transmission in South Africa, which feeds and rests both indoors and outdoors. This species is, therefore, not effectively targeted using core malaria vector control interventions alone. Additionally, increasing resistance to available insecticides necessitates investigations into complementary non-insecticide-based vector control methods for outdoor-resting mosquitoes. The feasibility of the sterile insect technique (SIT) as a complementary vector control intervention is being investigated in South Africa. Successful implementation of an SIT programme largely depends on inundating a target insect population with sterilized laboratory-bred males. Therefore, knowledge of the native population size and dispersal ability of released sterile laboratory-reared males is critical. In this study, we estimated the male An. arabiensis population size and the dispersal of released males in an area targeted for a pilot sterile male release programme. Methods Three separate releases were performed within a 2-year period. Approximately 5000–15,000 laboratory-reared male An. arabiensis (KWAG) were produced and marked for mark–release–recapture experiments. To recapture released mosquitoes, cloth tubes were deployed in widening concentric circles. The average dispersal distance of released males was calculated and the wild male An. arabiensis population size was estimated using two Lincoln index formulae. The natural population was sampled concurrently and Anopheles species diversity examined. Results The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions It was logistically feasible to conduct mark–release–recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time.

Transgenesis of Bioluminescence (BL) Gene and Its Potential Use for Malaria Residual Transmission Issue and Other Vector Borne Diseases: New Considerations for Vector and Vector Borne Diseases (VBD) Control

The present article considers the potential of transgenesis of the bioluminescent gene for malaria and other vector borne diseases (VBD) control. Vector control is an important component of every vector control operations for the vector borne disease control. Actually the bioluminescence phenomena and the green fluorescent protein GPF open great field of researches and “On December 10, 2008 Osamu Shimomura, Martin Chalfie and Roger Tsien were awarded the Nobel Prize in Chemistry for "the discovery and development of the green fluorescent protein, GFP". Bio-molecular technologies and transgenesis open the field for getting BL mosquitoes such as Plasmodium (several references) for “Transmission Reducing Activity” (TRA) without any hazard on human beings and ecological level. For exemple BL mosquitoes would be of paramount importance for mark-release-recapture becoming easier to implement and giving more relevant and reliable data on relation between density (size of the population) and distance (and wind) as the vector population size decrease with increasing distance from the source of production (breeding site) or release point. BL appeared already of great interest to understand the relation vector/parasite and to assess transmission intensity. Our idea is to genetically produce “Bioluminescent Mosquitoes” allowing a better identification of their presence, behavior, densities, infected specimens, risk of transmission before/after vector control operations which could be greatly improved thanks to the targeting of mosquitoes resting site or flight range and any other biological component.

How reliable is the use of transect counts to assess the population of the New Forest Burnet moth (Zygaena vicae [D. & S.], 1775) (Lepidoptera: Zygaenidae) at its only British site in western Scotland

The population of the New Forest burnet moth, Zygaena viciae, at its only UK site in western Scotland, was assessed between 1990 and 2019, using direct counts, standard transect counts and Mark/Release/Recapture (MRR). Data from eleven of these years, when reliable comparative transect counts and MRR population estimates were available, were analysed to answer the question as to whether the more economical transect counts provided a reliable estimate of the population size. Lin's Concordance Coefficient showed conclusively that transect counts do have a consistent relationship with the MRR population estimates. However, it was found that transect counts consistently under-estimate the MRR derived population estimates and that the scaling factor between them is best valued at ×5 (see Results). It can be concluded that, when resources are too limited to allow a full MRR population analysis, the more economical transect counts can trusted to indicate the relative size of the moth population.

Characterizing the spatial distributions of spotted lanternfly (Hemiptera: Fulgoridae) in Pennsylvania vineyards

Spotted lanternfly (SLF) is an invasive insect in the Northeastern U.S. projected to spread nationally and globally. While SLF is a significant pest of vineyards, little is known about the pest in grape agroecosystems including its spatial ecology. SLF spatial patterns were analyzed using a combination of approaches including generalized linear mixed effect models, Moran’s I statistic for spatial clustering, and Empirical Bayesian Kriging. Analysis revealed that SLF displayed significantly clumped distributions in monitored vineyards. Approximately 54% and 44% of the respective adult and egg mass populations were observed within the first 15 m of the vineyard edge. Importantly, the spatial concentration of adults at the edge was consistent temporally, both between years and weeks. Moreover, high populations of SLF on vines were significantly correlated with reduced fruit production in the following year. Mark-release-recapture of SLF revealed that higher proportions of SLF were recaptured on vines with high pre-existing SLF populations, indicating that SLF may exhibit aggregation behavior along vineyard perimeters. Monitoring and management efforts for SLF should be prioritized around vineyard edges as it may significantly reduce infestations and subsequent damage.