A Gap-Junction Mutation Reveals That Outer Hair Cell Extracellular Receptor Potentials Drive High-Frequency Cochlear Amplification.

Cochlear amplification enables the enormous dynamic range of hearing through amplifying cochlear responses to low- to moderate-level sounds and compressing them to loud sounds. Amplification is attributed to voltage-dependent electromotility of mechanosensory outer hair cells (OHCs) driven by changing voltages developed across their cell membranes. At low frequencies, these voltage changes are dominated by intracellular receptor potentials (RPs).

Auditory sensory range of male mosquitoes for the detection of female flight sound.

Male mosquitoes detect and localize conspecific females by their flight-tones using the Johnston's organ (JO), which detects antennal deflections under the influence of local particle motion. Acoustic behaviours of mosquitoes and their JO physiology have been investigated extensively within the frequency domain, yet the auditory sensory range and the behaviour of males at the initiation of phonotactic flights are not well known. In this study, we predict a maximum spatial sensory envelope for flying by integrating the physiological tuning response of the male JO with female aeroacoustic signatures derived from numerical simulations.

Optogenetics Reveals Control of Cochlear Electromechanical Responses by Supporting Cells.

Cochlear sensitivity, essential for communication and exploiting the acoustic environment, results from sensory-motor outer hair cells (OHCs) operating in a structural scaffold of supporting cells and extracellular cortilymph within the organ of Corti (OoC). Cochlear sensitivity control is hypothesized to involve interaction between the OHCs and OoC supporting cells (e.g.

Aerodynamic imaging by mosquitoes inspires a surface detector for autonomous flying vehicles.

Some flying animals use active sensing to perceive and avoid obstacles. Nocturnal mosquitoes exhibit a behavioral response to divert away from surfaces when vision is unavailable, indicating a short-range, mechanosensory collision-avoidance mechanism. We suggest that this behavior is mediated by perceiving modulations of their self-induced airflow patterns as they enter a ground or wall effect.

Pre-copula acoustic behaviour of males in the malarial mosquitoes Anopheles coluzzii and Anopheles gambiae s.s. does not contribute to reproductive isolation.

We reveal that males of two members of the Anopheles gambiae s.l. species complex, Anopheles coluzzii and Anopheles gambiae s.

Environmental Adaptation, Phenotypic Plasticity, and Associative Learning in Insects: The Desert Locust as a Case Study.

The ability to learn and store information should be adapted to the environment in which animals operate to confer a selective advantage. Yet the relationship between learning, memory, and the environment is poorly understood, and further complicated by phenotypic plasticity caused by the very environment in which learning and memory need to operate. Many insect species show polyphenism, an extreme form of phenotypic plasticity, allowing them to occupy distinct environments by producing two or more alternative phenotypes.

A role for acoustic distortion in novel rapid frequency modulation behaviour in free-flying male mosquitoes.

We describe a new stereotypical acoustic behaviour by male mosquitoes in response to the fundamental frequency of female flight tones during mating sequences. This male-specific free-flight behaviour consists of phonotactic flight beginning with a steep increase in wing-beat frequency (WBF) followed by rapid frequency modulation (RFM) of WBF in the lead up to copula formation. Male RFM behaviour involves remarkably fast changes in WBF and can be elicited without acoustic feedback or physical presence of the female.

Phenotypic transformation affects associative learning in the desert locust.

In desert locusts, increased population densities drive phenotypic transformation from the solitarious to the gregarious phase within a generation [1-4]. Here we show that when presented with odor-food associations, the two extreme phases differ in aversive but not appetitive associative learning, with solitarious locusts showing a conditioned aversion more quickly than gregarious locusts. The acquisition of new learned aversions was blocked entirely in acutely crowded solitarious (transiens) locusts, whereas appetitive learning and prior learned associations were unaffected.

A long-latency aversive learning mechanism enables locusts to avoid odours associated with the consequences of ingesting toxic food.

Avoiding food that contains toxins is crucial for the survival of many animals, particularly herbivores, because many plants defend themselves with toxins. Some animals can learn to avoid food containing toxins not through its taste but by the toxins' effects following ingestion, though how they do so remains unclear. We studied how desert locusts (Schistocerca gregaria), which are generalist herbivores, form post-ingestive aversive memories and use them to make appropriate olfactory-based decisions in a Y-maze.

Associative olfactory learning in the desert locust, Schistocerca gregaria.

Locusts can learn associations between olfactory stimuli and food rewards, and use the acquired memories to choose between foods according to their nutrient requirements. They are a model system for both the study of olfactory coding and insect nutritional regulation. Previous studies have used operant paradigms for conditioning freely moving locusts, restricting the study of the neural mechanisms underlying the acquisition of olfactory memories, which requires restrained preparations for electrophysiological recordings.