Open Questions Underfoot: teacher key

Bugs That Clean Up, grade 12 edition, written for 12th grade and up. Scientists still argue about how much the smallest soil animals matter to decay. Studies of leaves, wood, dung and beetle scents show what invertebrates do, and show what has never been tried.

Read the book. Print this page for the key.

Questions and answers

1. Why did one restoration study count only animals bigger than 5 mm?
   • Smaller animals were all springtails
   • The role of animals under 5 mm in decomposition is contentious (answer)
   • Smaller animals cannot live in soil
2. In the Puerto Rico wet forest, how much of the decomposition of tough Cecropia leaves did soil fauna account for, at most?
   • Up to 66 percent (answer)
   • About 3 percent
   • About 20-fold
3. How did restored sites with reintroduced invertebrates and fungi compare with control sites?
   • Decomposition was about the same
   • Decomposition was slower
   • Decomposition was significantly faster (answer)
4. What did the UConn team conclude about burying beetles and rival carrion feeders?
   • The beetles deceive rivals by changing the odor of their food (answer)
   • The beetles sterilize their food to keep rivals away
   • The beetles hide from rivals underground
5. Why might a researcher find it hard to pick which species to add when restoring decay?
   • Species are too rare to find
   • Species depend on each other (answer)
   • Species eat only wood

Words

• mesoinvertebrates: small spineless animals
• lignin: tough wood stuff
• detritivores: leftover eaters
• symbionts: partner microbes
• rewilding: bringing wildlife back