In this widely reported Plos One article, it is stated that, after roughly 3 decades of placing Malaise traps in a set of predetermined locations (counting and replacing them regularly), a sharp decline (roughly 75%) of insect population is observed. The idea is that the amount of insects caught in the traps is a proportionate representation of the insect population.
Maybe I didn't read the article thoroughly enough, but I saw no mention of the possibility that the local population (around where the traps are set) are adapting to avoid the traps. Since getting caught in a Malaise trap is lethal, genes that promote the behavior of avoiding those traps would thrive, in a local population of flies, at a higher proportion than their competitors. And since flies reproduce very quickly, 27 years seems (intuitively, to me) like a lot of time for this new local selection pressure, created by the experimenters, to make notable changes in a local fly population--particularly, their tendency to avoid Malaise traps.
Could the result of the linked article be explained by local flies adapting to the new selection pressure of Malaise traps?
When I first read about the methods with which the insect population drop was measured, this was the first possibility that came to my mind. But I can't find anywhere where this possibility is discussed. Could that be because it's so ridiculous that it's not even worth considering?