If Zonosemata flies whose own wings had been clipped and reattached were attacked more frequently than untreated flies, it would mean the surgery itself changed their risk of attack. This would make all the experimental results that involved wing surgery unreliable , because the manipulation introduces a new confounding variable (effects of the surgery), not just the intended test of wing pattern or behavior.

Core idea in simple terms

The experiment is supposed to test whether certain traits (like wing pattern or behavior) affect how often predators attack.
But if:

Flies with clipped and reattached wings are attacked more often than completely untreated flies,

then predators might be responding to:

  • altered flight ability,
  • changed appearance or damage from surgery,
  • stress or weakness from the procedure,

rather than only to the trait you wanted to test.

So the surgery becomes a confounding factor : it changes the outcome (attack rate) for reasons other than the independent variable you meant to study.

What becomes unreliable?

The accepted answer to this question in textbooks and homework solutions is:

All results for the experimental groups involving wing surgery would be invalid/unreliable.

That means:

  • Any group where wings were clipped and reattached (whether Zonosemata or another species) is compromised.
  • You can no longer say with confidence, “Predators attacked because of wing pattern/behavior,” because they might have attacked simply because the wings were surgically altered.

However:

  • Groups that did not undergo wing surgery (for example, untreated flies, or flies only painted or otherwise manipulated without clipping, if such groups exist) would not be directly affected.
  • The issue is not “all Zonosemata data” or “all housefly data”; it is specifically the data from any treatment that includes the wing surgery step.

So, in multiple-choice form, the correct interpretation (as many answer keys state) is:

“All results for the experimental groups involving wing surgery would be invalid.”

Why this undermines reliability

Reliability means your results are consistent and reflect only the variables you intend to test. If wing surgery alone changes attack frequency, then:

  1. The experiment no longer isolates the effect of wing pattern or behavior.
  2. Repeat trials might give different attack rates depending on subtle differences in how the surgery is performed.
  3. Any conclusions like “this wing pattern protects against predators” become questionable, because you cannot separate pattern effects from surgery effects.

A better design would include controls to ensure the surgery itself does not affect attack rates (for example, sham surgeries that do not alter wing function), or alternative methods that change the pattern without damaging the wings.

TL;DR:
If clipped-and-reattached Zonosemata wings cause more attacks, then the surgery is a confounding variable, and all results from groups that had wing surgery are no longer reliable; only non-surgery groups remain trustworthy.