Experimental investigation of insect deposition in lentic environments and implications for formation of Konservat-Lagerstätten

Terrestrial insects are often remarkably well preserved in lacustrine
Konservat-Lagerstätten. However, the assumption that carcasses should sink
fast through the water column seems to contradict evidence that this
scenario is unlikely due to excessive buoyancy and surface tension. The
mechanisms that promote rapid and permanent emplacement onto the sediment
surface (RPESS) of such terrestrial animal remains are not fully
understood. Here we use taphonomic experiments to show that floating in
water, growth of microbial biofilms and reception of rapid sediment load
promote RPESS of terrestrial insect remains in lentic water bodies. Our
results show that the optimum conditions for RPESS occur when terrestrial
insects enter a lentic water body in articulation, experience brief decay
in association with growth of microbes, then are buried rapidly by
airborne volcanic ash. These results provide a model for preservation of
articulated terrestrial insects and emphasize the importance of microbial
activity and volcanism for insect preservation in lacustrine
Konservat-Lagerstätten.