Decline of the insects’ populations, often dubbed “insect apocalypse”, is a subject for many controversies, over inconsistent and incoherent populational trends in different taxonomic groups and geographic regions. Most of the timeseries of the insect populations are originating from the monitoring efforts which started already well into the industrial era and are probably missing a true pre-decline baseline of said populations. This missing baseline and short duration of most time series (10-20 years) presents a difficulty for accessing true magnitude of insect decline. Viktor Baranov will talk about his studies of the aquatic insects decline, and how we can gain baseline for the decline studies using palaeobiological methods.