Where have all the beetles gone, long time passing?

This year was a no-show year for Japanese beetles, a relatively new pest in our area.  Flea beetles usually turn my potato's and eggplants' leaves into lace unless they are regularly dusted.  Bean beetles usually eat every legume in sight, and cucumber beetles usually deliver a bacterial wilt while feeding terminating the cucumber season by now.  June "bugs" just never appeared at all.  Populations of insects do fluctuate and oscillate, but such a coincidence makes you think that last year's drought and heat had a very negative impact on these populations.  For certain some of these beetles pupate underground, and for some reason, last year's extreme drought and heat may have killed them during this life stage.  Also, cicadas do not seem as numerous this year as they often are, and they may have been affected as well.  The chiggers were not affected at all; pardon while TPP stops and scratches his ankles.  What actual cause of these population declines remains uncertain.  Maybe conditions favored or encouraged or allowed more fungal infections (e.g., milky spore).  Hard to say the actual cause, but you tend to think environmental factors when it affects a multiple species particularly ones that either live in the same place or belong to the same group.  Hope it takes a few years for these populations to recover.