On a related vein of thought, one can almost model any currently-visible adults of a species with a high potential number of offspring-per-adult as a “surplus” that doesn’t necessarily have a large effect on trophic “throughput”. Phytoplankton come to mind as the extreme case; they sequester a huge quantity of carbon dioxide, but the oceans aren’t green (usually...) because huge quantities of them are constantly sinking to the ocean floor or being eaten. That small surviving fraction still reproduces at a high enough level to maintain themselves. (Land plants seem to have a very different equilibrium, which probably has something to do with… better herbivore control by predators, and maybe also counter-herbivore adaptations and the necessity of infrastructure-deployment to handle water scarcity? Not especially confident on this.)
Insects don’t have the reproductive rate of phytoplankton, though. And from the other comments, it sounds like this really is starving out some members of higher tropic levels.
For the former (German study with the biomass numbers), perhaps? For the review study (which reported on worldwide species numbers and Britain range distributions), I flipped through the supplement and it looks like they actually did try very hard to adjust for the fact that they were working off of volunteer data (Filtered for surveys that had identified certain other similar species, and which had lasted for over 1hr. Also, excluded some species that they expected to have “gone into hiding” more). Something interesting might be going on with the Beetles, but it seemed suggest that Butterfly/Moth and Wasp/Bee/Ant species are almost all either holding steady, or dropping. I think significant reductions in flying insect catches might actually be plausible.