Blowflies Slurp Their Drool To Keep From Overheating


Madison Dapcevich


Madison Dapcevich

Freelance Writer and Fact-Checker

Madison is a freelance science reporter and full-time fact-checker based in the wild Rocky Mountains of western Montana.

Freelance Writer and Fact-Checker

Drool, slurp, repeat. The blowfly uses its own spit to keep from overheating. Dorian Scharp/Shutterstock

Blowflies take the old adage “don’t sweat the small stuff” to a whole new level because, well, it turns out they don’t actually sweat to keep cool, they drool. 

The blowfly’s (Chrysomya megacephala) novel strategy is a new spin on an old method of adaptation. When the fly drools, the saliva hangs around the mouth and begins to lose heat. Once the droplet has cooled, the fly will then slurp the spit back up in a process known as evaporative cooling.


The team of researchers used micro-CT scanning to show that the loogie stays in the fly’s throat-like passage near the brain, lowering temperatures in the body by about 4°C below outside temperatures. Just like in this scene from Big Daddy, the fly will recycle the droplet several times. The researchers reported their finding at the annual meeting of the Society for Integrative and Comparative Biology

The blowfly's method of thermoregulation may be gross, but it helps scientists better understand our world. Temperature is a critical factor affecting the life of insects. Since insects make up more than half of the 1.5 million species that have been formally described, understanding how they adapt to their environment can help scientists piece together a bigger puzzle – one little bug at a time.

Mosquitoes use a similar technique when regulating their body temperature. The body temperature of mosquitoes tend to stay the same as their environment, meaning their body is as warm as the temperature outside. When slurping up warm blood, however, they experience an equally warm rise in body heat. A 2012 study published in Current Biology found that certain species of feeding mosquitos will release a blood-colored urine droplet to let go of some of the gained heat.

Temperature regulation is a balancing act between losing and gaining heat in an effort to adjust to outside temperatures. When a creature's body temperature is high, most critters get rid of heat by regulating blood pressure and the circulatory system, changing body posture, moving to a cooler spot, or bristling their fur or feathers.


Terrestrial animals also employ their own version of evaporative cooling but it in the form of sweating, salivating, licking, or panting. It works similar to an air conditioner – water (sweat) is released onto a warmer surface (skin) that then evaporates, creating a cooling effect. 

Insects, on the other hand, are cold-blooded animals whose body temperatures are reflective of their environment. Typically, they cool off by responding to their environment. 

Drool, slurp, repeat – it may sounds like a gross way to stay cool, but it helps these little flies survive. 

[H/T: Science News]


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