Two is a crowd but three’s a party

Most people like being in a group, humans are social creatures. but did you know that bugs also do that too? They also come together into groups to socialize. Socializing helps keep them alive. The bugs I’m specifically talking about are terrestrial isopods. They have tons of different names people call them: sowbugs, pillbugs, roly poly’s, woodlice. But for now we’ll just call them pillbugs.


This is a terrestrial Isopod aka a pillbug photo taken from: Here


These bugs come together for tons of different reasons. The main reason is to avoid desiccation. Desiccation is when the bugs dry out and die. This is because pillbugs originally come from the sea and have modified gills! these gills need to stay moist in order to survive. So in order to help keep them moist the bugs aggregate together. what is aggregation you ask? here let me show you. 

Screen Shot 2015-12-10 at 10.52.38 AM

Aggregation shown in terrestrial Isopods. credit from the Broly et al. 2014 paper Click here

Essentially it is when pillbugs come together to form clumps. When they form clumps it helps trap moisture, keeps them nice and moist. But most important keeps them breathing.


Deep breaths taken from here


BUT aggregation doesn’t only happen to help them breath. Aggregation is actually broken down into two types: nonsocial and social aggregation

Nonsocial aggregation occurs when pillbugs come together but only because of the environment. They come together because they are moving to more favorable conditions. They only need to tolerate each other’s presence and do nothing else (just like what I do with my siblings, I tolerate their existence)  

Social aggregation occurs when pillbugs come together for the sole purpose of interacting with each other (in humans it’s like hanging out with friends, we only hang out with them because we want to). Pill bugs come together for a variety of reasons. These would include for protection, figuring out where the food is, Avoiding drying out and also, depending on the time of year, for mating purposes.

In my experiment, I looked at what will change aggregation behaviors in pill bugs. temperature? humidity? light? substrate? there was so many to chose from so I picked 3: cohabitation, environmental type, and light intensity. Having them live together for a week didn’t change if they clumped together or not. neither did the two environment types i looked at (dirt and leaf clutter). However light had an effect on aggregation! The pill bugs are more likely to clump together in the presence of light! (isn’t that exciting?! I had significant results!)

why does this matter?   one word: climate change

ok let me explain. As temperatures increase, chance of desiccation in pillbugs also increases. If pill bugs can’t survive the change then we lost an important decomposer as well as food source for other animals. (oh no!) so seeing if they can adapt to the changes is important!

in the end, this just goes to show you how important being in a group is


Gif credit from tumblr Click here

Thanks again for reading my post! I hoped you learned a little about aggregation!

if interested in learning more click the links below


– Jonathan Kim



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