photoreceptor systems converge in arousal neurons and confer light responsive robustness.

Lateral ventral neurons (LNvs) in the fly circadian neural circuit mediate behaviors other than clock resetting, including light-activated acute arousal. Converging sensory inputs often confer functional redundancy. The LNvs have three distinct light input pathways: (1) cell autonomously expressed cryptochrome (CRY), (2) rhodopsin 7 (Rh7), and (3) synaptic inputs from the eyes and other external photoreceptors that express opsins and CRY.

Nocturnal mosquito Cryptochrome 1 mediates greater electrophysiological and behavioral responses to blue light relative to diurnal mosquito Cryptochrome 1.

Nocturnal Anopheles mosquitoes exhibit strong behavioral avoidance to blue-light while diurnal Aedes mosquitoes are behaviorally attracted to blue-light and a wide range of other wavelengths of light. To determine the molecular mechanism of these effects, we expressed light-sensing Anopheles gambiae (AgCRY1) and Aedes aegypti (AeCRY1) Cryptochrome 1 (CRY) genes under a crypGAL4-24 driver line in a mutant Drosophila genetic background lacking native functional CRY, then tested behavioral and electrophysiological effects of mosquito CRY expression relative to positive and negative CRY control conditions. Neither mosquito CRY stops the circadian clock as shown by robust circadian behavioral rhythmicity in constant darkness in flies expressing either AgCRY1 or AeCRY1.

Mosquito cryptochromes expressed in Drosophila confer species-specific behavioral light responses.

Cryptochrome (CRY) is a short-wavelength light-sensitive photoreceptor expressed in a subset of circadian neurons and eyes in Drosophila that regulates light-evoked circadian clock resetting. Acutely, light evokes rapid electrical excitation of the ventral lateral subset of circadian neurons and confers circadian-modulated avoidance behavioral responses to short-wavelength light. Recent work shows dramatically different avoidance versus attraction behavioral responses to short-wavelength light in day-active versus night-active mosquitoes and that these behavioral responses are attenuated by CRY protein degradation by constant light exposure in mosquitoes.

Circadian Regulation of Light-Evoked Attraction and Avoidance Behaviors in Daytime- versus Nighttime-Biting Mosquitoes.

Mosquitoes pose widespread threats to humans and other animals as disease vectors [1]. Day- versus night-biting mosquitoes occupy distinct time-of-day niches [2, 3]. Here, we explore day- versus night-biting female and male mosquitoes' innate temporal attraction/avoidance behavioral responses to light and their regulation by circadian circuit and molecular mechanisms.

Distinct mechanisms of CRYPTOCHROME-mediated light-evoked membrane depolarization and in vivo clock resetting.

CRYPTOCHROME (dCRY) mediates electrophysiological depolarization and circadian clock resetting in response to blue or ultraviolet (UV) light. These light-evoked biological responses operate at different timescales and possibly through different mechanisms. Whether electron transfer down a conserved chain of tryptophan residues underlies biological responses following dCRY light activation has been controversial.

Multiple Phototransduction Inputs Integrate to Mediate UV Light-evoked Avoidance/Attraction Behavior in .

Short-wavelength light guides many behaviors that are crucial for an insect's survival. In , short-wavelength light induces both attraction and avoidance behaviors. How light cues evoke two opposite valences of behavioral responses remains unclear.