Collaborative Research: Cretaceous Insects and the Origins of Modern Insect Diversity

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Insects are the most diverse class of organisms in the 3.5 billion years of life on earth, and one (but not exclusive) explanation for this is that insects radiated in the Cretaceous as plant feeders and pollinators along with the radiation of the dominant form of plant life, the angiosperms. In other words: insects may be exceptionally diverse because plants speeded their rate of origin or speciation. This theory will be addressed by studying diverse species of insects fossilized in ancient resin (amber) from around the world, including hundreds of specimens from 3 collections in the United States, 2 in Canada, and 5 in the UK, Spain, France, Russia, and Germany. Specimens range in age from 120 to 70 million years old, and study will focus on the megadiverse orders Diptera (flies) and Hymenoptera (ants, bees, wasps), with additional work on the Lepidoptera (moths) and termites. The amber will be meticulously prepared and detailed microscopic study will be made of the insect inclusions, along with photomicrographs, detailed illustrations and descriptions, and the specimens will then be compared to living and other extinct species to determine phylogenetic relationships. If angiosperms affected the evolution of insects, then groups of insects that today are intimately associated with angiosperms (like gall midges and gall wasps) will show rapid diversification in the Late Cretaceous and Tertiary, whereas the diversification of predatory and scavenger insects should not be timed to that of angiosperms. A low rate of extinction can also increase diversity, and this study will also address whether insects were less affected by extinctions at the Cretaceous-Tertiary boundary 65 mya that killed off other major groups of terrestrial life. The intricate, life-like preservation in amber provides unique scientific and educational opportunities. Virtually all morphological characters found in living species are visible in amber fossils, thus allowing profoundly accurate measures of the amount of change over vast expanses of time and discerning the relationships of extinct life forms. With this, scientists can directly confront criticisms about the incompleteness of the fossil record for revealing evolutionary change. Also, the esthetic appeal of fossils preserved in amber engages the public with insect diversity, fossils, evolution and the history of life in general, as well as with the interface between biology and earth history. Besides the formal education of students in systematics, entomology, and paleontology, this research will promote informal science education through a new web site and popular publications.