Bugs, Worms, and Leaf Litter…..O my! (Adding detritivores to EcoColumns)

Adding worms is almost as much fun as getting a fish!  (NO FISH for two weeks–seriously, don’t do it)

After a week of letting the seeds germinate and grow, its time to add bugs.  Students will also measure their plant height, take soil data, and add to the spreadsheet on this day.

Student directions for building ecocolumns.

Read about buying supplies, cutting and filling bottles, planting seeds and taking data in previous posts. 

Adding Detritivores

Students should take terrestrial chamber data today-before or after adding detritivores: Plant heights and observations. Soil data also if you have probes or kits (optional).

We add detritivores (insects that decompose) which allows students to learn more about nutrient cycling. NO herbivores as they will eat all the seedlings and plants.  NO carnivores (spiders, lady bugs) as they won’t have any food and will crawl/fly away. NO crawling or flying insects as they will escape.  (Believe me, you don’t want crickets chirping in your building) Initially, my students think the sprinkler top will keep the crawling bugs in, but I tell them we discard/recycle the sprinkler top soon as they plants need more room to grow.

You can take the kids on a bug hunt around campus or have them collect and bring from home. I tell kids to bring from home–go in their yards or the park and turn over rocks to find bugs and worms.  I also tell them that if they’re SUPER WIMPY they can buy worms at Walmart (bait/fishing section) and mealworms at the pet store (not a worm, but beetle larvae).

The best detritivores are ones that are easily found are earthworms, pill-bugs/sowbugs/roly polys, pinscher bugs, and beetles. Be careful as some will find caterpillars which are super cool, but eat all the plants.

Worms and bugs that a student collected at home.
Purchased worms.
Directions for students.
Handling worms is new for some kids. “Nope, you don’t need gloves”.

Side note: There is a way to add a non-venemous spider to your ecocolumns. You can have students add a piece of fruit to a chamber in order to attract fruit flies. When the flies arrive, you now have a food source for spiders. I don’t do this, but have heard its possible.

Providing Leaf Litter

Bugs need hiding places and food and leaf litter provides all that. My students go outside and collect a few green and brown leaves. They tear up and line the soil with leaf litter. They must be careful to avoid smothering seedlings. Its been a week since seeds were planted so most have germinated and grown at this point.

Students continue to drain their chambers. The more silt that flushes through, the better it is for the fish. Fish are not added for 2 weeks.

My students live in the Chaparral (well, technically in the suburbs surrounded by Chaparral), so many have never heard of “leaf litter” or know its function. This is a great opportunity for them to learn that in addition to hiding places and food for the detritivores, leaf litter prevents water loss, prevents erosion, and add nutrients to the soil.

Students take notes to help them understand the scientific concepts in ecocolumns. They will use these notes and their data to help answer analytical questions later and to make connections.

From experience, I’ve found that students need help with the scientific concepts in ecocolumns. A lot of the concepts are inferred and cannot be directly observed (part of biogeochemical cycles, for example).  Just making observations and having them research what’s going doesn’t lead them to the immense amount they can potentially learn. Scaffolding is important. I give notes and then refer to these concepts all the time. Students then have to process their notes, data and observations in more higher-level ways. The AP Exam contains 2/3 higher level thinking questions so these skills are important. 

To find time for these essential skills, I flipped my class last year and enjoy the time to build higher-level thinking in my students. Even with the time, after a few weeks of ecocolumns, I train my students to spend only 10 minutes taking data.

Students store in my hallway under plant lights. I’ve purchased several banks with grant money. Window also work.

In an additional week, its time to build the aquatic chamber and add a fish.