Experiment
He created five experimental groups
2-Zonosemata with own wings re-glued
3-Zonosemata with housefly wings
4-Houseflies with Zonosemata wings
He subjected flies from each treatment to starved jumping spiders and other predators, conducted 20 trials, measured number of times spider or other predator attacks v.s. retreats.
Questions-Why group 2? Why not just 1 trial?