Let it go, let it go, can’t hold it back anymore.
An iconic line from the movie Frozen and just like the name would predict, someone was froze in the movie. Just like them, we are gonna turn our isopods into isopod-cicles (get it? isopod + popscicle … I’m getting ahead of myself)
Anyways, ever heard of cryogenic freezing? This is when an individual is frozen and later come back to life! (just like a zombie!… not really but kind of… anyways). We essentially did the same thing to our insects (specifically isopods). We took insects from terrestrial or earthy environments and marine environments and placed them in ice for different amounts of time and then timed how long it took for them to come back to “life”.
Putting our marine isopod into the world of frozen (ice). Taken by Jonathan Kim (aka me)
In both types of environments, these isopods are able to withstand a huge flux of temperatures. However, lets look at how they deal with the cold. Did you know invertebrates have different ways of interacting with the cold? (I sure didn’t). Since invertebrates are ectothermic, their body temperature changes with the environmental temperature. When the temperature gets too cold, they undergo a chill coma. A chill coma is when they get so cold they lose neuromuscular movement and can’t move! But don’t worry; they can recover from this perfectly fine with zero side effects. (what a relief)
We aren’t the only ones that induced chill comas on insects, Western University biologists Brent Sinclair and Heath McMillan studied crickets in chill comas1. The wanted to figure out the mechanisms behind chill comas and found out that ion concentrations may play a role in chill comas.
here is a fall field cricket in a chill coma and a cricket being readied to be chilled. Images found from http://mediarelations.uwo.ca/2012/11/26/cold-cricket-case-could-defrost-mysteries-of-changing-climate/ and http://www.lfpress.com/2012/11/28/insects-response-to-cold-studied respectively.
Once placed in a chill coma, we waited in our lab for them to wake up. Some got up really quickly while others struggled in waking up just like me every monday morning.
Just like this sloth, some of the isopods did not want to wake up. Taken from pinterest https://www.pinterest.com/pin/41799102768051065/.
However having them in chill comas for too long can cause some serious damage. When in a chill coma for too long, this can cause a chill injury. Chill injuries are when the individual is in a chill coma for too long and can cause long lasting negative effects.
To deal with the extreme cold, ectothermic animals have many different ways to cope with it. When things get too cold, they freeze! This means that the body water in the animal has been completely converted into ice! Unlike Bobby (aka Iceman from X-men) being made of ice is not a good thing! We need blood to be in a liquid state so that the body can get nutrients. How can the body get nutrients if the blood is ice? Nothing can move thus no nutrients, we call these animals chill susceptible.
There are a few ways they cope with the cold. These would be the freeze avoiding and freeze tolerant animals2. If they are freeze avoiding animals, they depress their cooling point (sometimes even to -40°C! THAT’S INSANE!). Freeze tolerant animals actually survive with the ice in their body (just like Bobby!).
on the right is the Wooly bear Caterpillar that is freeze tolerant, able to survive with ice inside its body just like bobby aka iceman (on left). Taken from https://featuredcreature.com/moth-looks-exactly-like-those-adorable-woolly-bear-caterpillars/ and https://en.wikipedia.org/wiki/Iceman_(comics) respectively.
Whether they are chill susceptible and can’t tolerate the cold or are freeze tolerant animals similar to the Iceman, each animal interacts differently to its environment but that’s what makes our world so interesting!
If you are still interested in learning more, here are more studies about chill comas3.
- http://1. http://www.lfpress.com/2012/11/28/insects-response-to-cold-studied a news article about the study of chill comas on crickets done by Brent Sinclair and Heath McMillan
- http://flynnthecat.hubpages.com/hub/freezing-strategies More information about the difference between freeze tolerant and freeze avoiding
- http://www.ncbi.nlm.nih.gov/pubmed/12838605 a scientific paper talking about invertebrates and chill coma