Insects in ecosystems

Activities to try

1. 1

   Build the web, then remove the insects

   Why it works: Pulling out insects doesn't remove one thread — it unravels many parts of the web, because insects were doing four different jobs at once. Interdependence means a change in one part ripples across many.

   1. Start with one familiar food chain (e.g. plant → caterpillar → bird) and draw it with arrows showing who eats what.
   2. Add more strands until insects sit at the centre wearing several hats: pollinator (bee), decomposer (dung beetle, fly larva), food (caterpillar for birds, bats, fish, frogs), and pest controller (ladybird keeping aphids down).
   3. Remove all insects from the web and trace each knock-on effect out loud or in writing: insect-pollinated flowers bloom but set little or no fruit or seed, so fruit-eaters go hungry; dung and leaf litter break down more slowly and pile up; birds, bats and frogs that ate insects decline. Notice that aphids are insects too, so they would also vanish. To see the pest-control job, run a separate what-if where only the ladybirds are removed: aphids are no longer kept down, their numbers can surge, and they can damage the plants.
   4. Then restore roles one at a time and note which job fixed which problem (returning pollinators brings back fruit on insect-pollinated plants; in the ladybird-only what-if, where aphids are still present, returning ladybirds helps bring aphids back under control).
2. 2

   Open thought experiment with an ecologist

   Why it works: Cascade reasoning branches: removing insects produces many consequences on different timescales, and a good prediction follows several of them rather than stopping at the first.

   1. Pose and explore open 'what would REALLY happen if insects vanished?' questions, predicting an outcome first before checking the reasoning.
   2. Reason about timing: some effects would be fast (pollination failing within a season, insect-eating animals struggling to feed their young; or, if only ladybirds vanished, aphids surging) and some slow (soil nutrient cycling, effects spreading along long food chains), so predictions should distinguish quick from gradual consequences.
   3. Defend predictions when challenged with Socratic probes and revise them when a branch doesn't hold up.
3. 3

   Sort, sequence and judge removal consequences

   Why it works: The expected answer is to disagree: losing insects breaks pollination, decomposition and food webs all at once, so consequences reach plants, vertebrates and humans. Full understanding names multiple distinct roles AND traces knock-on effects, rather than listing one role.

   1. Match each insect to its ecological role (bee↔pollinator, dung beetle↔decomposer, caterpillar↔food source, ladybird↔pest controller).
   2. Categorise several insects by the role(s) they fill, noting that some fill more than one.
   3. Put a cause-and-effect chain in order (e.g. remove pollinators → insect-pollinated plants set little or no fruit → fruit-eaters go hungry).
   4. Choose the correct single consequence of removing one role from among plausible options (a short multiple-choice check).
   5. Answer the scenario: 'Every insect on Earth vanishes overnight. A child says that would be great — no annoying bugs and nothing important changes. Do you agree? Walk through what happens to plants, other animals, and us, and explain why.'