Answer:
All results for the experimental groups involving wing surgery would be invalid.
Explanation:
The experimental group involving wing surgery would not lead to correct results because it is a direct parameter that is impaired. This has been already clearly stated in the question that these flies are prone to attack compared to those which are not treated. There could be several reasons for that such as: (1) the reattachment would not have been successful, and/or (2) the flies' health (fitness) status would have been compromised.
On the other hand, it is not correct that all experimental groups will lead to incorrect results because the untreated flies were not attacked (or less attacked). Similarly, there is no condition given for houseflies rather only zonosemata flies. So 3rd option is also not possible. Finally, the reliability of the results would definitely change because the treated flies would be more attacked and lead to a clear difference in results.
