USING MODERN INSECTS AND RESINS TO REVEAL ECOLOGICAL DETAILS IN ANCIENT AMBER DEPOSITS

Many of the groups of insects that characterize modern ecosystems began their rise to dominance in the Cretaceous, around the same time that amber deposits start to become more abundant within the rock record. At the family level, analogies can be drawn between amber-entombed insects and their modern descendants, permitting some ecological inferences in deep time. Instances where groups of insects are repeatedly found as syninclusions, (trapped within the same pieces of amber), or are caught in the act of committing specific behaviors, provide some of the most detailed records of biotic interactions available in the fossil record. Over the last two decades, the chemical and stable isotopic composition of the surrounding amber has also become a valuable source of ecological data, allowing us to draw analogies between the formation of modern resins and amber deposits, and to address both specific and larger-scale ecological questions. Combining these two approaches has been particularly fruitful for amber deposits found in association with other fossil remains. We can now use minute amber samples in our search for ancient insects, to inform on the types of trees present within paleo-forests, and to investigate some of the ecological conditions experienced by these trees. Amber samples that were once considered too small or fragile to warrant study are now being studied in the context of dinosaur bonebeds and other fossil deposits – providing detailed glimpses of the forests that were present at the time, and a new facet to paleoecological reconstructions.