I show students this video of ants at Saguaro National Park and ask them what they observe. At the start of any lesson, I want them immediately engaged in conversation. It doesn't always have to be a rigorous conversation.
I explain to students that today they will engage in a simple simulation in which they will play the role of ants collecting food. Prior to explaining the rules for the kinesthetic simulation, I ask them to think about this question:
If some ants are working as a group to collect food, and will share what they gather equally, and others are collecting food as an individual, who will end up with the most food?
I also remind the students that we engage in this kind of activity to get them to think while having a chance to move about and that it is not to be considered a real representation of natural ant behavior. They are, after all, thinking like people!
Here is one student's explanation of why he thinks individual "ants" will be more successful:
This simple (limited) simulation of how cooperative behavior in eusocial insects such as ants might work can be demonstrated with a group of children and a bag full of any ordinary classroom objects. I used pattern blocks and 4 emptied out crayon buckets.
I present the students with a scenario in which they were tasked with collecting food, one piece at a time, and bringing it back to the nest. (One of them pointed out that they could be collecting levels that would then be used to grow fungi for the larvae). Five or six of them were to work as a group, and deposit their food in the same "nest". They would divide it equally at the completion of the food collection period. There were also 3 solo ants, seen in the video with a red tag on theri back. That had to collect on their own but they also didn't need to share. They may only carry one piece of "food" at a time and they can only walk, not run. I also told them they could move on half bent legs. (They like to crawl, but the industrial carpet in my room is sharp and when they were rabbits a week ago, several of them cut their legs). Here is a short clip of the ants collecting food and bringing it back to the nest:
Read and discuss this passage on cooperative behavior in ants.
This interesting video shows (unusual) communal spiders in the Democratic Republic of the Congo. Note: at 18 seconds it says, "A place explorers once called The Green Hell." This is just FYI, in case that is not something which you are able to explain as contextual to your students.
This is great for grabbing students' attention. The key points to highlight are the fact that the spiders work communally in the rainforest of Congo because (theoretically) their webs are constantly being destroyed by deluges of rain and animals running through them, so hypothetically they couldn't build successful webs fast enough to catch food on their own. It is very unusual for spiders to be social. Only 23 of 39000 spider species are social and some of them are distantly related, as shown in this phylogenetic map. When I show this to students, all I point out is that each different line represents different spider groups (no way to draw 39000 lines) and that the further away they are from one another, the more distantly they are related. (Note: Phylogenetic tree of spiders is from Evolution, 2006, Argnasson).