Abstract Detail


Schachat, Sandra R. [1].

A critical reassessment of angiosperms' role in insect diversification.

Angiosperms and insects form the foundation of modern terrestrial ecosystems. Because countless insect species are specialist pollinators and herbivores of angiosperms, it is difficult to imagine insects such as bees or butterflies diversifying during a time when flowering plants were rare or absent. And yet, whereas angiosperms only came to dominate the landscape during the Cretaceous, crown representatives of the major modern groups of insects (bugs; wasps, including ants and bees; beetles; flies; moths, including butterflies) had all originated by the Triassic. For nearly two hundred million years, ending during the Cretaceous, insects were fundamentally modern in a way that plants were not. The existence of modern insects in gynmosperm-dominated ecosystems serves as a fascinating natural experiment that informs fundamental paleobiological questions such as the role of contingency in shaping the taxonomic composition of ecosystems as we know them.
I reconstructed the family-level diversity of insects throughout the Phanerozoic using the capture–mark–recapture (CMR) method, which is uniquely well-suited to the insect fossil record. This method accounts for the incompleteness of the insect fossil record as well as uneven sampling among time intervals. The CMR diversity curve shows extinctions at the Permian/Triassic and Cretaceous/Palaeogene boundaries but does not contain any mass extinctions within geological periods. This curve also includes a steep increase in diversity during the Aptian, which appears not to be an artifact of sampling or preservation bias because this increase still appears when time bins are standardized by the number of occurrences they contain rather than by the amount of time that they span. The Early Cretaceous increase in family-level diversity predates the rise of angiosperms by many millions of years and can be better attributed to the diversification of parasitic and especially parasitoid insect lineages.

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Publication in Proceedings B

1 - Stanford University, Geological Sciences, 450 Jane Stanford Way Bldg. 320, Stanford, CA, 94305-2070, US

plant-insect interactions
insect pollination

Presentation Type: Oral Paper
Session: PAL2, Cookson Award Session II
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 1:15 PM
Number: PAL2003
Abstract ID:811
Candidate for Awards:Isabel Cookson Award

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