Biology subjects

Su, M. P.

Publications and source records attributed to Su, M. P..

10 recordsLinked to original sources

bioRxiv2026

The sex determination gene doublesex is essential for female-specific flight and hearing properties in Aedes aegypti mosquitoes

The acoustic communication system supporting reproduction in disease-transmitting mosquitoes is sexually dimorphic, from the sounds that mosquitoes make to the properties of their flagellar ears. The molecular mechanisms shaping these dimorphisms, however, remain unclear. Here, we explored the contributions of the female-specific isoform of the sex determination gene doublesex (dsxF) in specifying female-unique properties in the acoustic communication system of Aedes aegypti mosquitoes. CRISPR-Cas9 based generation of a novel dsxF knockout line found that dsxF mutant females were flightless due to lack of expression of a female-specific myosin gene, myo-fem, in the thorax. We found that DsxF directly binds to four different enhancer sites of myo-fem to promote gene expression. We observed that dsxF female ears exhibited intersex neuroanatomical characteristics and contained a more extensive auditory efferent network than control females. At the peripheral hearing function level, dsxF female ears displayed intersex tuning frequencies associated with increased expression of hearing genes in dsxF female ears compared to control females. We identified three hearing genes transcriptionally inhibited by DsxF via direct binding. DsxF is a bifunctional transcription factor, activating female-specific gene expression in thoraces whilst repressing male-biased gene expression in ears to coordinate female-unique features across sensory and motor systems.

neuroscience↗

bioRxiv2026

The sex determination gene fruitless is essential for male Aedes aegypti mosquito swarming and attraction to female flight sounds

Aggregating male mosquitoes locate females by showing strong and innate attraction to female flight sounds, with these behaviors forming the basis of mating in the worlds deadliest animal. In contrast, females do not show aggregation or sound attraction behaviors. Despite being documented for almost a century, the molecular underpinnings of these behavioral dimorphisms remain unknown. Here, we found that by disrupting the male-specific isoform of the key sex determination gene fruitless (referred to as fruM) in Aedes aegypti, mutant males behave like females. fruM mutant males show complete abolition of aggregation and sound attraction behaviors, resulting in failure to locate females for mating. We identified strong fruitless expression in control male ears, with the loss of FruM severely disrupting mutant male ability to amplify female flight sounds compared to control males. fruM mutant male ears propagate frequency-specific, sound-evoked electrical signals at about one-sixth the magnitude of control males, significantly reducing the amount of auditory information relayed to the brain. fruitless thus plays a significant role in determining proper male peripheral hearing function, which enables male hearing behaviors essential for mating. Transcriptomic analyses of mosquito ears enabled identification of essential hearing genes under the transcriptional influence of FruM. We propose that FruM fine-tunes the masculinization of mosquito ears through shaping male-specific hearing cellular machineries that support male attraction to female flight sounds. We conclude that FruM is the master regulator of male-specific reproductive behaviors in mosquitoes and propose fruitless, as well as fruitless-dependent genes, as novel targets for control strategies. HighlightsO_LIFruM is the master regulator of male swarming and attraction to female flight sounds C_LIO_LIFruM in male ears is essential for male amplification of female flight sounds C_LIO_LIFruM in male ears modulates sound-evoked electrical signal propagation to the brain C_LIO_LIFruM regulates essential hearing gene expression C_LI

neuroscience↗

bioRxiv2025

cAMP-related second messenger pathways modulate hearing function in Aedes aegypti mosquitoes

The powerful ears of male Aedes aegypti mosquitoes facilitate identification and localization of mating partners via detection of female flight tones. Male hearing function is modulated by the efferent release of neurotransmitters, though the secondary mechanisms underlying this modulation remain unclear. Here, we investigated these mechanisms using octopamine as a model, as octopamine modulates hearing function and the erection status of fibrillar hairs lining male ears. We found that pharmacological interference with octopamine receptors alters hearing function at multiple levels and identified the second messenger cAMP as likely mediating these changes. Furthermore, the erection status of male ear fibrillar hairs could be altered by targeting specific sub-types of octopamine receptors, but these changes were not linked to changes in ear frequency tuning. Finally, we suggest that octopamine 2 receptors linked to fibrillar hair erection may not always produce functional proteins across species, with downstream implications for hearing behaviors. HighlightsO_LIOctopamine and its receptors are found throughout Aedes aegypti mosquito ears C_LIO_LIPharmacological interference with octopamine receptors modulates hearing function C_LIO_LIModulating levels of the second messenger cAMP also alters hearing function C_LIO_LIEar frequency tuning does not correlate with the erection of hairs lining male ears C_LI

neuroscience↗

bioRxiv2025

Using a female-specific isoform of doublesex to explore male-specific hearing in mosquitoes

Animal reproduction relies on elaborate divisions of labour and multiple dimorphisms between the sexes. Primary dimorphisms affect core elements of reproduction, secondary dimorphisms affect more indirect traits, including complex behaviours. In disease-transmitting mosquitoes, males locate females acoustically prior to copulation (phonotaxis). No comparable acoustic behaviour is known for females. As a result, the males ears - and hearing performance - have evolved to become substantially more complex. Sex-specific hearing in mosquitoes is in part controlled by the doublesex (dsx) gene. Intriguingly, dsx forms a linker between primary and secondary dimorphisms: spermatogenesis and ear morphogenesis share considerable molecular overlap and both depend on dsx expression patterns. We have combined transcriptomics with functional-anatomical analyses to dissect dsx-dependent hearing in the malaria mosquito Anopheles gambiae. By cross-linking our auditory findings to the genetic bases of spermatogenesis we advance the molecular understanding of sex-specific hearing mechanisms in insects, highlighting the special roles of ciliary factors therein. HighlightsO_LIDisruption of the female-specific exon of the doublesex gene alters hearing in female Anopheles gambiae mosquitoes C_LIO_LIFemale mutant ears are anatomically and functionally distinct from both wild-type male and female; they show a substantial, but incomplete, masculinisation C_LIO_LIContrary to males, and similarly to females, the flagella of female mutants do not exhibit Self-Sustained Oscillations (SSOs) C_LIO_LITranscriptomic comparisons of ears uncovered molecular bases of auditory maleness, these were closely linked to molecular machinery of ciliary function C_LIO_LIComparisons with existing transcriptome from male testes revealed a substantial overlap between male ear and testicular ciliary motility machineries C_LI

neuroscience↗

bioRxiv2024

Sexually dimorphic auditory representation in Aedes aegypti brains

Male attraction to female flight sounds is a vital, reproducible component of courtship in many species of mosquitoes; however, female acoustic behaviours have proven challenging to define. To investigate sexual dimorphisms in acoustic behaviours, previous reports have largely focused on differences in mosquito peripheral ear anatomy and function. Whilst molecular investigations have recently begun on the auditory periphery, sexual dimorphisms in central processing of acoustic information have not yet been explored. Here we used a combination of neurotracing, calcium imaging and molecular analyses to examine sexual dimorphisms in auditory processing in the yellow fever mosquito Aedes aegypti. We identified shared and dimorphic neurons connecting male and female ears to the primary auditory processing centre in the brain, and defined multiple distinct neuronal clusters based on responses to auditory stimulation. We finally used transcriptomic and proteomic analyses to investigate the molecular factors underlying these differences, with motile ciliary-related terms significantly enriched in males.

neuroscience↗

bioRxiv2024

The voltage-gated potassium channel Shal (Kv4) contributes to active hearing in Drosophila

The full complement of ion channels which influence insect auditory mechanotransduction, and the mechanisms by which their influence is exerted, remain unclear. Shal (Kv4), a Shaker family member encoding voltage-gated potassium channels in Drosophila melanogaster, has been shown to localize to dendrites in some neuron types, suggesting a potential role for Shal in Drosophila hearing, including mechanotransduction. A GFP-protein trap was used to visualize the localization of the Shal channel in Johnstons organ neurons responsible for hearing in the antenna. Shal protein was localized to the cell body and the proximal dendrite region of sensory neurons, suggesting its involvement not only in general auditory function, but specifically in mechanotransduction. Electrophysiological recordings conducted to assess neural responses to auditory stimuli in mutant Shal flies revealed significant decreases in auditory responses. Laser Doppler Vibrometer recordings indicated abnormal antennal free fluctuation frequencies in mutant lines, indicating an effect on active antennal tuning, and thus active transduction mechanisms. This suggests that Shal participates in coordinating energy-dependent antennal movements in Drosophila that are essential for tuning the antenna to courtship song frequencies. Significance StatementThe study of fruit fly hearing has revealed mechanosensitive ion channels that participate in mechanotransduction, and as in mammalian hearing, energy-dependent mechanisms actively amplify and tune auditory processes. Identifying distinct roles played by different ion channels is essential to better understand this process. Here, we explore the influence of a specific voltage-gated potassium channel, Shal, on fly hearing, and find that it affects specific parts of the mechanotransduction process. Our research uncovers Shals localization in sensory dendrite regions of auditory neurons, where it contributes to shaping mechanotransduction and active antennal tuning. Understanding Shals involvement in auditory function and mechanotransduction deepens our knowledge of fly hearing and unveils a key player in the coordination of energy-dependent active antennal movements.

neuroscience↗

bioRxiv2023

Targeting Sex Determination to Suppress Mosquito Populations

Each year, hundreds of millions of people are infected with arboviruses such as dengue, yellow fever, chikungunya, and Zika, which are all primarily spread by the notorious mosquito Aedes aegypti. Traditional control measures have proven insufficient, necessitating innovations. In response, here we generate a next generation CRISPR-based precision-guided sterile insect technique (pgSIT) for Aedes aegypti that disrupts genes essential for sex determination and fertility, producing predominantly sterile males that can be deployed at any life stage. Using mathematical models and empirical testing, we demonstrate that released pgSIT males can effectively compete with, suppress, and eliminate caged mosquito populations. This versatile species-specific platform has the potential for field deployment to effectively control wild populations of disease vectors.

bioengineering↗

bioRxiv2023

Mechanical transmission of Dengue Virus by Aedes aegypti may influence disease transmission dynamics during outbreaks

The escalating number of dengue virus (DENV) outbreaks and their worldwide spread pose a major threat to global public health. DENV transmission dynamics significantly influence outbreak duration and magnitude. Conventional DENV transmission requires an incubation period between mosquitoes biting infected humans and the mosquitoes becoming infectious. However, the possibility of immediate, mechanical transmission of DENV without viral replication in the mosquito has received little attention despite its potential importance. Here, we show that Aedes aegypti mosquitoes can mechanically transmit DENV to susceptible mice immediately after biting infected mice without the need for an incubation period. By incorporating parameters from our experiments into a newly developed mathematical model, we found a significant impact on DENV outbreak characteristics. Mechanical transmission may amplify existing disease transmission routes and influence outbreak dynamics. Our findings have implications for vector control strategies that target mosquito lifespan and suggest the possibility of similar mechanical transmission routes in other disease-carrying mosquitoes.

microbiology↗

bioRxiv2021

Flight-tone mediated circadian control of audibility in mating swarms of Anopheles mosquitoes

Mating swarms of malaria mosquitoes form every day at sunset throughout the tropical world, they typically last less than 30 minutes. Activity patterns must thus be highly synchronized between the sexes. Moreover, males must be able to identify the few sporadically entering females by detecting the females faint flight tones. We here show that the Anopheles circadian clock ensures a tight synchrony of male and female activity and -importantly - also retunes the males acoustic detection system: by lifting their own flight tones at dusk, males actively enhance the audibility of females. The reported phenomenon of harmonic convergence is a random by-product of the mosquitoes flight tone variance. Intriguingly, flight tones of individual mosquitoes occupy narrow -partly non-overlapping-frequency ranges, suggesting that the audibility of individual females varies across males. One Sentence SummaryMale mosquitoes sharpen their hearing at sunset.

neuroscience↗

bioRxiv2020

Assessing the acoustic behaviour of Anopheles gambiae s.l. dsxF mutants: Implications for Vector Control

BackgroundThe release of genetically modified mosquitoes which use gene-drive mechanisms to suppress reproduction in natural populations of Anopheles mosquitoes is one of the scientifically most promising methods for malaria transmission control. However, many scientific, regulatory and ethical questions remain before transgenic mosquitoes can be utilised in the field. Mutations which reduce an individuals reproductive success are likely to create strong selective pressures to evolve resistance. It is thus crucial that the targeted population collapses as rapidly and as completely as possible to reduce the available time for the emergence of drive-resistant mutations. At a behavioural level, this means that the gene-drive carrying mutants should be at least as (and ideally more) sexually attractive than the wildtype population they compete against. A key element in the copulatory negotiations of Anopheles mosquitoes is their acoustic courtship. We therefore analysed sound emissions and acoustic preference in a doublesex mutant previously used to successfully collapse caged colonies of Anopheles gambiae s.l.. MethodsThe flight tones produced by the beating of their wings form the signals for acoustic mating communication in Anopheles species. We assessed the acoustic impact of the disruption of a female-specific isoform of the doublesex gene (dsxF) on the wing beat frequency (WBF; measured as flight tone) of both males (XY) and females (XX) in homozygous dsxF- mutants (dsxF-/-), heterozygous dsxF- carriers (dsxF+/-) and G3 wildtype dsxF+ controls (dsxF+/+). To exclude non-genetic influences, we controlled for temperature and measured wing lengths for all experimental animals. We used a phonotaxis assay to test the acoustic preferences of mutant and control mosquitoes. ResultsA previous study demonstrated an altered phenotype only for females homozygous for the disrupted dsx allele (dsxF-/-), who appear intersex. No phenotypic changes were observed for heterozygous carriers or males, suggesting that the female-specific dsxF allele is haplosufficient. We here identify significant, dose-dependent increases in the flight tones of both dsxF-/- and dsxF+/- females when compared to dsxF+/+ control females. Flight tone frequencies in all three female genotypes remained significantly lower than in males, however. When tested experimentally, males showed stronger phonotactic responses to the flight tones of control dsxF+/+ females. While flight tones from dsxF+/- and dsxF-/- females also elicited positive phonotactic behaviour in males, this was significantly reduced compared to responses to control tones. We found no evidence of phonotactic behaviour in any female genotype tested. None of the male genotypes displayed any deviations from the control condition. ConclusionsA key prerequisite for copulation in anopheline mosquitoes is the phonotactic attraction of males towards female flight tones within large - spatially and acoustically crowded - mating swarms. Reductions in acoustic attractiveness of released mutant lines, as reported here for heterozygous dsxF+/- females, reduce the lines mating efficiency, and could consequently reduce the efficacy of the associated population control effort. Assessments of caged populations may not successfully reproduce the challenges posed by natural mating scenarios. We propose to amend existing testing protocols in order to more faithfully reflect the competitive conditions between a mutant line and the wildtype population it is meant to interact with. This should also include novel tests of acoustic fitness. In line with previous studies, our findings confirm that disruption of the female-specific isoform dsxF has no effect on males; for some phenotypic traits, such as female flight tones, however, the effects of dsxF appear to be dose-dependent rather than haplosufficient.

animal behavior and cognition↗