No one enjoys that groggy feeling the day after a disturbed night. Everything feels like wading through mud, from your movements to your thoughts; the following bedtime can't come soon enough. And we are not alone, even honeybees and fruit flies struggle after a sleepless night. But what about one of our arch nemeses: mosquitoes? How do these blood sucking pests cope after a disturbed night's sleep? Joshua Benoit and Clément Vinauger, from the University of Cincinnati, USA, with colleagues also from Cincinnati and Virginia Tech, USA, filmed three species of mosquito (Aedes aegypti, Culex pipiens and Anopheles stephensi, which actively feast on blood at different times of day) to find out more about their slumber and how sleep loss affects them.
Although most alert mosquitoes stand on four of their six legs, the slumbering insects slumped on all six limbs while the abdomens of sleeping Cx. pipiens and An. stephensi – which tilt up while conscious – drooped. The insects were also groggy, taking longer to arouse when woken by an intruder. Also, the mosquitoes nodded off more slowly (2 hours) than frenetic fruit flies, which drop off in just 5 minutes. In addition, Ae. aegypti mosquitoes, which tend to dine through the day, were sleepiest at night, Cx. pipiens, which prefer to suck blood at dusk, slept during the latter half of the night and the nocturnal diners, An. stephensi, snoozed through the day.
But how well did the insects cope when Oluwaseun Ajayi repeatedly nudged them into wakefulness every 5 minutes? Not very well. Aedes aegypti and An. stephensi both had to make up for lost slumber the following night (or day for An. stephensi), sleeping several hours more, and when the team tested how badly sleep deprivation affected Ae. aegypti, the insects dined 54% less often than when well rested.
Mosquitoes definitely sleep, and they suffer as badly as us after a disturbed night, which could have implications for some of the diseases transmitted by these pernicious pests. ‘To acquire a pathogen, mosquitoes must feed when an animal is available and the pathogen is in the blood. If sleep deprivation shifts this process, transmission can be increased or decreased, but follow-up studies will be needed’, says Benoit.
