By: Leena Thorat, York University
What is the first thing you normally do when you wake up in the morning? Chances are you use water! Water is essential for our survival, and we are advised to drink 8 glasses of water a day. We cannot imagine life without water but some amazing insects have a trick- they can quietly survive without water and become active once better conditions return! In 2017 I published a study with my team where we showed that insects such as the midges (also known as bloodworms) can tolerate loss of body water and shrivel up like raisins and interestingly, can spring back to life once they are given water again!
Hot, dry conditions are tough on living things because they lose water faster than they can replace it. Well, let us first imagine what could happen to us when we go hiking on a hot, sunny day. We expect to sweat more than usual, our mouth could dry up and we could feel dizzy and even faint. You might expect a similar situation in insects, where they lose body water, dry out, and die. Our study on a tropical species of midge worms shows that while they do dry out under desert-like conditions, they don’t necessarily die, even after losing 80% of their body water.
Chironomid midges are aquatic insects found in freshwater and marine ecosystems. Since they live in water, they are dependent on water for all their life activities. So how do they survive dry and hot climate? Our research confirmed that one of the secrets of midge worms to overcome dry conditions in their habitats is to huddle together, just like how penguins tightly pack together in groups to avoid freezing to death. Using this trick, midges conserve body water and reduce the risk of drying up too easily. However, their soft and thin outer body covering is not alone sufficient to avoid water loss. In another previously published study, we have shown that midges build a nest in which they take shelter to stay safe from harsh drying summer conditions because becoming a husk of an insect isn’t exactly a good thing, even if they can survive it.
What’s more? Apart from these behavioural strategies, chironomid midges bring about a few chemical changes in their body. Our research indicates that midge worms produce special sugars that have the ability to hold onto water. They protect cells and organs from damage and death caused due to water loss and shrinkage. Such special chemicals make sure that the worms remain quiet in the dry state without dying, until they get water again.
So why is this important and why should we care? The recent 2021 incidences of floods (western Germany and central China), heatwaves and wildfires (western Canada and the US) and drought as an ever-present risk for live and agriculture (Middle East and Southeast Asia) are proof and warnings that our climate is changing. Even the largest of lakes and rivers are gradually drying up due to the extreme changes in climate that lead to drought and water shortage as the demand for water rises for the growing population on earth. Insects are intelligent animals and can do things humans never can. Since insects are exposed to different kinds of climate conditions in diverse habitats including extremely hot regions, they can help us predict how living things could respond to stressful environments. We can learn about the possible health risks of extreme heat conditions on humans. And by applying their tricks to cope with low water availability to biomedical research, we can save lives by developing protective measures and medications against heat illnesses such as heat stroke and exhaustion, extreme thirst and dehydration and changes in breathing patterns and heart functioning.
I am extremely passionate about understanding the secret life of insects without water. Currently I am studying the role of the insect brain and hormones and the mechanisms by which insects sense extreme heat changes in their environments.
Edited by B.G. Borowiec and A.E. McDonald. Header image from Unsplash. Additional images by Leena Thorat.
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