Insect Predation Game
Students learn about interspecific competition and population and ecosystem dynamics through a fun and dynamic game. They are introduced to adaptations, prey and predator relationships, food chains and evolution.
Students will use plastic cutlery made into three types of appendages developed for foraging different types of prey. There are three prey species represented by three types of beans. With every round of the game, the populations change and some species develop novel adaptations poison or resistance to poison.
What You Need
- Plastic forks, spoons and knives
- Small paper cups for stomachs
- Rubber bands
- Cotton sheet/plastic foil/big paper to put prey beans on it
- 3 types of beans at least 300 of each - any kidney-shaped beans, chickpeas, lentils
- Computer with PowerPoint and Excel + projector
Guide:
Safety Notes
Ensure you are familiar with Let's Talk Science's precautions with respect to safe virtual outreach to youth.
What To Do
Sample Script:
In this class, we will focus on predator-prey relationship and how can it affect the community. As I have mentioned, there are adaptations that predators will develop to catch a certain type of prey. What do you think are those insects specialized for (what kind of appendages)? Dragonflies have grasping legs for catching a prey, mantis has raptorial legs and beetles mandibles. I brought knives, forks and spoons. Which one would represent which type of predator appendages?
We have three kinds of prey (beans). As you can see, some predators will be better at catching certain types of prey. You will have 45 seconds for foraging, which means searching and catching prey. Small cups will represent your stomachs where you put the prey you catch, and if you fill it up, you are done. After every round of foraging, we will try to see what happens to the community.
Your stomachs cannot be used for grabbing food, only your specialized appendages. Stomachs are used only to store food. You can steal from others, but only from their appendages, not from their stomachs.
As we mentioned, prey can also develop adaptations, but we don't know which ones, because we still didn't adapt to recognize it. You will all try to catch any kind of prey and after 30 seconds I will tell you which kind of prey is not edible. If you had any of them in your stomach, you will throw up and continue eating for the last 15 seconds. Now you will learn which ones are not good for you and will avoid them in future.
After we are done with foraging, you will count how many beans (prey) and what kinds you have in your stomach. Counting represents digestion of prey and predators will be able to eat again after they have digested all the food. You will have prey populations of 200 and after you count how many have been eaten, we will see the change.
*Play round 1 of the game*
Before the next round, something else will also happen. Insects can grow in numbers by mating. The edible prey will reproduce faster (3 from 1) than inedible (1 from 1) because often adaptations can affect something else and the balance in the community will be maintained. Because there are often limiting factors in the environment (e.g. lack of food), the limit for prey populations is 300. To determine which one will grow at which rate – write numbers on the board. Highest number – 3x, second – 2x, poisonous – 1x growth. Tell them to form 3 groups depending on their appendages and count together. When counting, they should separate different kinds of beans. On the board, it will be easier to sum prey numbers from all groups, then to let them count twice or count individually.
Predator numbers will also have to change with every round. Why is that so? Some predators are better adapted to catching prey, so the ones that catch more will be better at surviving and will reproduce more. The ones that don't eat enough may start to die out. That means that some of you will have to change your specialised appendages in the next round.
During the next round, after 30 seconds, some of the predators will adapt to be resistant to poison that is produced by the poisonous species (make it the one that is lowest in numbers to prolong the game). They will now be able to eat all the species. Others will be restricted to only two types of prey. How will this affect the predators that can eat poisonous prey? How will it affect other two predator species?
We will calculate successfulness of predators by the formula: amount eaten by predator 1/amount eaten by all predators. Since everyone will play every round, we will figure out which predators will increase and which will decrease in numbers. (Population growth/reduction will be adjusted to the amount of prey eaten). Change predator numbers arbitrarily, but according to the calculated percentages. If mandibles ate 3x more than raptorial legs and raptorial legs 2x more than grasping legs, then for 29 students 9:10:10 will change into e.g. 14:9:6.
*Play round 2 of the game*
In the next round, there will be one prey species that will also become poisonous. You will know which one after 30 seconds and if you ate them, you will vomit. What do you expect will happen to the predators that are not resistant to poison?
*Play round 3.* The game ends when one of the species goes extinct.