scholarly journals Synchronized swarming: Harmonic convergence and acoustic mating dynamics in the malaria mosquito Anopheles gambiae

2021 ◽  
Author(s):  
Stefano S. Garcia Castillo ◽  
Kevin S. Pritts ◽  
Raksha S. Krishnan ◽  
Laura C. Harrington ◽  
Garrett P. League
Keyword(s):  
Anopheles Gambiae ◽  
Mosquito Control ◽  
Control Strategies ◽  
Activity Data ◽  
Mating Activity ◽  
Promising Alternative ◽  
Male And Female ◽  
Single Sex ◽  
Harmonic Convergence ◽  
Mating Biology

The mosquito Anopheles gambiae is a major African malaria vector, transmitting parasites responsible for significant mortality and disease burden. Malaria declines have stagnated recently due to widespread insecticide resistance among vector populations. Flight acoustics are essential to mosquito mating biology and represent promising alternative targets for mosquito control. However, mosquito swarm acoustics data are limited. Here, for the first time, we present detailed analyses of free-flying male and female An. gambiae flight tones and their harmonization (harmonic convergence) over a complete swarm sequence. Audio analysis of single-sex swarms showed elevated male or female flight tone frequencies and amplitudes during swarming flight with gradual declines to pre-swarm levels over an approximately 35-min period. Analysis of mixed-sex swarms revealed additional increases in flight tone frequencies and amplitudes due to mating activity. Data from mixed-sex swarms suggest harmonic convergence during swarming enhances the efficiency of female detection by synchronizing male and female baseline swarm tones. Further, data from experiments using female swarm tone playbacks to males indicate that harmonic convergence during mating interactions coordinates male scramble competition by acoustically masking mating couple flight tones. These findings advance our knowledge of mosquito swarm acoustics, providing vital information for reproductive control strategies.

scholarly journals Harmonic convergence coordinates swarm mating by enhancing mate detection in the malaria mosquito Anopheles gambiae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefano S. Garcia Castillo ◽  
Kevin S. Pritts ◽  
Raksha S. Krishnan ◽  
Laura C. Harrington ◽  
Garrett P. League
Keyword(s):  
Anopheles Gambiae ◽  
Control Strategies ◽  
Mating Activity ◽  
Male And Female ◽  
Audio Analysis ◽  
Single Sex ◽  
Reproductive Control ◽  
Harmonic Convergence ◽  
Mosquito Anopheles Gambiae ◽  
First Time

AbstractThe mosquito Anopheles gambiae is a major African malaria vector, transmitting parasites responsible for significant mortality and disease burden. Although flight acoustics are essential to mosquito mating and present promising alternatives to insecticide-based vector control strategies, there is limited data on mosquito flight tones during swarming. Here, for the first time, we present detailed analyses of free-flying male and female An. gambiae flight tones and their harmonization (harmonic convergence) over a complete swarm sequence. Audio analysis of single-sex swarms showed synchronized elevation of male and female flight tones during swarming. Analysis of mixed-sex swarms revealed additional 50 Hz increases in male and female flight tones due to mating activity. Furthermore, harmonic differences between male and female swarm tones in mixed-sex swarms and in single-sex male swarms with artificial female swarm audio playback indicate that frequency differences of approximately 50 Hz or less at the male second and female third harmonics (M2:F3) are maintained both before and during mating interactions. This harmonization likely coordinates male scramble competition by maintaining ideal acoustic recognition within mating pairs while acoustically masking phonotactic responses of nearby swarming males to mating females. These findings advance our knowledge of mosquito swarm acoustics and provide vital information for reproductive control strategies.

scholarly journals Compensatory mechanisms in resistant Anopheles gambiae AcerKis and KdrKis neurons modulate insecticide-based mosquito control

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Stéphane Perrier ◽  
Eléonore Moreau ◽  
Caroline Deshayes ◽  
Marine El-Adouzi ◽  
Delphine Goven ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Anopheles Gambiae ◽  
Calcium Concentration ◽  
Mosquito Control ◽  
Point Mutations ◽  
Resting Membrane Potential ◽  
Compensatory Mechanisms ◽  
Pyrethroid Insecticides

AbstractIn the malaria vector Anopheles gambiae, two point mutations in the acetylcholinesterase (ace-1R) and the sodium channel (kdrR) genes confer resistance to organophosphate/carbamate and pyrethroid insecticides, respectively. The mechanisms of compensation that recover the functional alterations associated with these mutations and their role in the modulation of insecticide efficacy are unknown. Using multidisciplinary approaches adapted to neurons isolated from resistant Anopheles gambiae AcerKis and KdrKis strains together with larval bioassays, we demonstrate that nAChRs, and the intracellular calcium concentration represent the key components of an adaptation strategy ensuring neuronal functions maintenance. In AcerKis neurons, the increased effect of acetylcholine related to the reduced acetylcholinesterase activity is compensated by expressing higher density of nAChRs permeable to calcium. In KdrKis neurons, changes in the biophysical properties of the L1014F mutant sodium channel, leading to enhance overlap between activation and inactivation relationships, diminish the resting membrane potential and reduce the fraction of calcium channels available involved in acetylcholine release. Together with the lower intracellular basal calcium concentration observed, these factors increase nAChRs sensitivity to maintain the effect of low concentration of acetylcholine. These results explain the opposite effects of the insecticide clothianidin observed in AcerKis and KdrKis neurons in vitro and in vivo.

scholarly journals The regulatory genome of the malaria vector Anopheles gambiae: integrating chromatin accessibility and gene expression

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
José L Ruiz ◽  
Lisa C Ranford-Cartwright ◽  
Elena Gómez-Díaz
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Anopheles Gambiae ◽  
Mosquito Control ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Malaria Vectors ◽  
Specific Gene ◽  
Mosquito Vector ◽  
Human Malaria

Abstract Anopheles gambiae mosquitoes are primary human malaria vectors, but we know very little about their mechanisms of transcriptional regulation. We profiled chromatin accessibility by the assay for transposase-accessible chromatin by sequencing (ATAC-seq) in laboratory-reared A. gambiae mosquitoes experimentally infected with the human malaria parasite Plasmodium falciparum. By integrating ATAC-seq, RNA-seq and ChIP-seq data, we showed a positive correlation between accessibility at promoters and introns, gene expression and active histone marks. By comparing expression and chromatin structure patterns in different tissues, we were able to infer cis-regulatory elements controlling tissue-specific gene expression and to predict the in vivo binding sites of relevant transcription factors. The ATAC-seq assay also allowed the precise mapping of active regulatory regions, including novel transcription start sites and enhancers that were annotated to mosquito immune-related genes. Not only is this study important for advancing our understanding of mechanisms of transcriptional regulation in the mosquito vector of human malaria, but the information we produced also has great potential for developing new mosquito-control and anti-malaria strategies.

scholarly journals Mosquito Control Priorities in Florida—Survey Results from Florida Mosquito Control Districts

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 947
Author(s):  
Rishi Kondapaneni ◽  
Ashley N. Malcolm ◽  
Brian M. Vazquez ◽  
Eric Zeng ◽  
Tse-Yu Chen ◽  
...  
Keyword(s):  
State Government ◽  
Mosquito Control ◽  
Control Strategies ◽  
Mosquito Species ◽  
Research Priorities ◽  
Current Control ◽  
Control Programs ◽  
Common Control ◽  
Surveillance Programs ◽  
Research Questions

Florida lies within a subtropical region where the climate allows diverse mosquito species including invasive species to thrive year-round. As of 2021, there are currently 66 state-approved Florida Mosquito Control Districts, which are major stakeholders for Florida public universities engaged in mosquito research. Florida is one of the few states with extensive organized mosquito control programs. The Florida State Government and Florida Mosquito Control Districts have long histories of collaboration with research institutions. During fall 2020, we carried out a survey to collect baseline data on the current control priorities from Florida Mosquito Control Districts relating to (1) priority control species, (2) common adult and larval control methods, and (3) major research questions to address that will improve their control and surveillance programs. The survey data showed that a total of 17 distinct mosquito species were considered to be priority control targets, with many of these species being understudied. The most common control approaches included truck-mounted ultra-low-volume adulticiding and biopesticide-based larviciding. The districts held interest in diverse research questions, with many prioritizing studies on basic science questions to help develop evidence-based control strategies. Our data highlight the fact that mosquito control approaches and priorities differ greatly between districts and provide an important point of comparison for other regions investing in mosquito control, particularly those with similar ecological settings, and great diversity of potential mosquito vectors, such as in Florida. Our findings highlight a need for greater alignment of research priorities between mosquito control and mosquito research. In particular, we note a need to prioritize filling knowledge gaps relating to understudied mosquito species that have been implicated in arbovirus transmission.

Acarine biocontrol agents Neoseiulus californicus sensu Athias-Henriot (1977) and N. barkeri Hughes (Mesostigmata: Phytoseiidae) redescribed, their synonymies assessed, and the identity of N. californicus (McGregor) clarified based on examination of types

Zootaxa ◽  
2018 ◽  
Vol 4500 (4) ◽  
pp. 451 ◽  
Author(s):  
FRÉDÉRIC BEAULIEU ◽  
JENNIFER J. BEARD
Keyword(s):  
Biocontrol Agent ◽  
Species Concept ◽  
Biocontrol Agents ◽  
International Commission ◽  
Neoseiulus Californicus ◽  
Zoological Nomenclature ◽  
Male And Female ◽  
Crop Pests ◽  
Type Host ◽  
Single Sex

In 1954, McGregor described two species of phytoseiids from lemon, in California, USA: Typhlodromus californicus McGregor and T. mungeri McGregor, the former represented by one male, and the latter by two females. Since its description, T. mungeri was synonymised under T. californicus, and the name T. (now Neoseiulus) californicus has been used extensively to represent a species that is now commonly used as a biocontrol agent of crop pests worldwide. However, the true identity of the biocontrol agent is uncertain because the original descriptions of T. californicus and T. mungeri were not adequate enough to allow an irrefutable identification, with each description being based on specimens of a single sex. An examination of the types of N. californicus and N. mungeri revealed that they are morphologically identical to the male and female of N. barkeri Hughes, 1948, respectively, and that they are in fact junior synonyms of N. barkeri—and are therefore distinct from the biocontrol agent globally called N. californicus (sensu Athias-Henriot, 1977; see Griffiths, 2015). This is further supported by a comparison with male and female syntypes of N. barkeri, as well as other specimens of N. barkeri including some collected from the type host in the vicinity of the type location (i.e. lemon in southern California, 1952–1958). We redescribe the male and female of both N. barkeri and N. californicus sensu Athias-Henriot (1977), based on representative specimens from at least 14 and 19 populations, respectively. Based on examination of types, we confirm the synonymy of N. mckenziei (Schuster & Pritchard, 1963), N. picketti (Specht, 1968), and N. oahuensis (Prasad, 1968) with N. barkeri, and that the names N. chilenensis (Dosse, 1958b) and N. wearnei (Schicha, 1987) represent the same species as N. californicus sensu Athias-Henriot (1977). We also provide a hypothesis as to why Chant (1959) had erroneously synonymised T. californicus and T. mungeri under T. marinus (Willmann). Finally, we suggest maintaining the prevailing usage of the name N. californicus (McGregor) for the species concept of Athias-Henriot (1977) as followed by subsequent authors, through submission of a separate application to the International Commission of Zoological Nomenclature (ICZN). In the meantime, the current meaning of N. californicus should be maintained until a ruling by the ICZN is made on the application. 

scholarly journals Discovery of Novel Entomopathogenic Fungi for Mosquito-Borne Disease Control

2021 ◽  
Vol 2 ◽  
Author(s):  
Anastasia Accoti ◽  
Cecilia Springer Engdahl ◽  
George Dimopoulos
Keyword(s):  
Entomopathogenic Fungi ◽  
Mosquito Control ◽  
Control Strategies ◽  
Pathogenic Fungi ◽  
Suitable Alternative ◽  
Control Programs ◽  
Wide Range ◽  
Outdoor Environments ◽  
Environmentally Safe ◽  
Emergence Of Resistance

The increased application of chemical control programs has led to the emergence and spread of insecticide resistance in mosquitoes. Novel environmentally safe control strategies are currently needed for the control of disease vectors. The use of entomopathogenic fungi could be a suitable alternative to chemical insecticides. Currently, Beauveria spp. and Metarhizium spp. are the most widely used entomopathogenic fungi for mosquito control, but increasing the arsenal with additional fungi is necessary to mitigate the emergence of resistance. Entomopathogenic fungi are distributed in a wide range of habitats. We have performed a comprehensive screen for candidate mosquitocidal fungi from diverse outdoor environments in Maryland and Puerto Rico. An initial screening of 22 fungi involving exposure of adult Anopheles gambiae to 2-weeks-old fungal cultures identified five potent pathogenic fungi, one of which is unidentified and the remaining four belonging to the three genera Galactomyces sp., Isaria sp. and Mucor sp. These fungi were then screened against Aedes aegypti, revealing Isaria sp. as a potent mosquito killer. The entomopathogenic effects were confirmed through spore-dipping assays. We also probed further into the killing mechanisms of these fungi and investigated whether the mosquitocidal activities were the result of potential toxic fungus-produced metabolites. Preliminary assays involving the exposure of mosquitoes to sterile filtered fungal liquid cultures showed that Galactomyces sp., Isaria sp. and the unidentified isolate 1 were the strongest producers of factors showing lethality against An. gambiae. We have identified five fungi that was pathogenic for An. gambiae and one for Ae. aegypti, among these fungi, four of them (two strains of Galactomyces sp., Mucor sp., and the unidentified isolate 1) have never previously been described as lethal to insects. Further characterization of these entomopathogenic fungi and their metabolites needs to be done to confirm their potential use in biologic control against mosquitoes.

A note on the housing of intact male and female pigs together in the same pen during the growing period to bacon weight

1980 ◽  
Vol 31 (3) ◽  
pp. 321-322 ◽  
Author(s):  
R. S. Barber ◽  
R. Braude ◽  
K. G. Mitchell ◽  
Joanne Thomas
Keyword(s):  
Feed Intake ◽  
Live Weight ◽  
Intake Rate ◽  
Feeding Trial ◽  
Intact Male ◽  
Male And Female ◽  
Gain Ratio ◽  
Growing Period ◽  
Single Sex ◽  
Dressing Percentage

ABSTRACTA feeding trial was carried out, using 180 pigs, to assess the effect on performance when intact male and female pigs were housed together in the same pens from 20 to 90 kg live weight. There were no significant differences in daily feed intake, rate of growth or feed: gain ratio between pigs from mixed-sex pens and pigs from single-sex pens. Carcass measurements indicated slightly leaner carcasses for intact male pigs whether housed in separate pens or together with female pigs, while female pigs likewise had a significantly higher dressing percentage.

scholarly journals Mosquitoes of Etiological Concern in Kenya and Possible Control Strategies

Insects ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 173 ◽  
Author(s):  
Samuel Karungu ◽  
Evans Atoni ◽  
Joseph Ogalo ◽  
Caroline Mwaliko ◽  
Bernard Agwanda ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Mosquito Control ◽  
Control Strategies ◽  
Mosquito Species ◽  
Disease Outbreaks ◽  
Health Concern ◽  
Public Health Concern ◽  
Vector Management ◽  
Invasive Mosquito ◽  
Parasitic Pathogens

Kenya is among the most affected tropical countries with pathogen transmitting Culicidae vectors. For decades, insect vectors have contributed to the emergence and distribution of viral and parasitic pathogens. Outbreaks and diseases have a great impact on a country’s economy, as resources that would otherwise be used for developmental projects are redirected to curb hospitalization cases and manage outbreaks. Infected invasive mosquito species have been shown to increasingly cross both local and global boarders due to the presence of increased environmental changes, trade, and tourism. In Kenya, there have been several mosquito-borne disease outbreaks such as the recent outbreaks along the coast of Kenya, involving chikungunya and dengue. This certainly calls for the implementation of strategies aimed at strengthening integrated vector management programs. In this review, we look at mosquitoes of public health concern in Kenya, while highlighting the pathogens they have been linked with over the years and across various regions. In addition, the major strategies that have previously been used in mosquito control and what more could be done to reduce or combat the menace caused by these hematophagous vectors are presented.

scholarly journals Comparison of the Physical Demands of Single-Sex Training for Male and Female Recruits in the British Army

2012 ◽  
Vol 177 (6) ◽  
pp. 709-715 ◽  
Author(s):  
Victoria L. Richmond ◽  
James M. Carter ◽  
David M. Wilkinson ◽  
Fleur E. Horner ◽  
Mark P. Rayson ◽  
...  
Keyword(s):  
British Army ◽  
Physical Demands ◽  
Male And Female ◽  
Single Sex

scholarly journals Novel Method for the Separation of Male and Female Gametocytes of the Malaria Parasite Plasmodium falciparum That Enables Biological and Drug Discovery

mSphere ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Melanie C. Ridgway ◽  
Kwong Sum Shea ◽  
Daniela Cihalova ◽  
Alexander G. Maier
Keyword(s):  
Flow Cytometry ◽  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Disease Transmission ◽  
Severe Form ◽  
Male And Female ◽  
Content Type ◽  
Single Sex ◽  
Parasite Plasmodium Falciparum ◽  
Female Bias

ABSTRACT We developed a flow-cytometry-based method to separate and collect cocultured male and female Plasmodium falciparum gametocytes responsible for malaria transmission. The purity of the collected cells was estimated at >97% using flow cytometry, and sorted cells were observed by Giemsa-stained thin-smear and live-cell fluorescence microscopy. The expression of validated sex-specific markers corroborated the sorting strategy. Collected male and female gametocytes were used to confirm three novel sex-specific markers by quantitative real-time PCR that were more enriched in sorted male and female gametocyte populations than existing sex-specific markers. We also applied the method as a proof-of-principle drug screen that allows the identification of drugs that kill gametocytes in a sex-specific manner. Since the developed method allowed for the separation of male and female parasites from the same culture, we observed for the first time a difference in development time between the sexes: females developed faster than males. Hence, the ability to separate male and female gametocytes opens the door to a new field of sex-specific P. falciparum gametocyte biology to further our understanding of malaria transmission. IMPORTANCE The protozoan Plasmodium falciparum causes the most severe form of human malaria. The development of sexual forms (so-called gametocytes) is crucial for disease transmission. However, knowledge of these forms is severely hampered by the paucity of sex-specific markers and the inability to extract single sex gametocytes in high purity. Moreover, the identification of compounds that specifically affect one sex is difficult due to the female bias of the gametocytes. We have developed a system that allows for the separation of male and female gametocytes from the same population. Applying our system, we show that male and female parasites mature at different rates, which might have implications for transmission. We also identified new sex-specific genes that can be used as sex markers or to unravel sex-specific functions. Our system will not only aid in the discovery of much needed gametocidal compounds, but it also represents a valuable tool for exploring malaria transmission biology.

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