Biology subjects

Loh, Y. M.

Publications and source records attributed to Loh, Y. M..

5 recordsLinked to original sources

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↗

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↗