Ancient origin of high taxonomic richness among insects

TY - JOUR

T1 - Ancient origin of high taxonomic richness among insects

AU - Clapham, Matthew

AU - Karr, Jered

AU - Nicholson, David

AU - Ross, Andrew

AU - Mayhew, Peter John

N1 - Embargo period: 12 months. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

PY - 2016/2/3

Y1 - 2016/2/3

N2 - Insects are a hyper-diverse group, comprising nearly three-quarters of all named animal species on Earth, but the environmental drivers of their richness and the roles of ecological interactions and evolutionary innovations remain unclear. Previous studies have argued that family-level insect richness increased continuously over the evolutionary history of the group, but inclusion of extant family records artificially inflated the relative richness of younger time intervals. Here we apply sampling standardisation methods to a species-level database of fossil insect occurrences, removing biases present in previous richness curves. We show that insect family richness peaked 125 million years ago and that recent values are only 1.5-3 times as high as the late Palaeozoic. Rarefied species richness data also tentatively suggest little or no net increase in richness over the past 125 Myr. The Cretaceous peak in family richness was coincident with major radiations within extant groups but occurred prior to extinctions within more basal groups. Those extinctions may in part be linked to mid-Cretaceous floral turnover following the evolution of flowering plants. Negligible net richness change over the past 125 Myr implies that major radiations within extant groups were offset by reduced richness within groups that are now relict or extinct.

AB - Insects are a hyper-diverse group, comprising nearly three-quarters of all named animal species on Earth, but the environmental drivers of their richness and the roles of ecological interactions and evolutionary innovations remain unclear. Previous studies have argued that family-level insect richness increased continuously over the evolutionary history of the group, but inclusion of extant family records artificially inflated the relative richness of younger time intervals. Here we apply sampling standardisation methods to a species-level database of fossil insect occurrences, removing biases present in previous richness curves. We show that insect family richness peaked 125 million years ago and that recent values are only 1.5-3 times as high as the late Palaeozoic. Rarefied species richness data also tentatively suggest little or no net increase in richness over the past 125 Myr. The Cretaceous peak in family richness was coincident with major radiations within extant groups but occurred prior to extinctions within more basal groups. Those extinctions may in part be linked to mid-Cretaceous floral turnover following the evolution of flowering plants. Negligible net richness change over the past 125 Myr implies that major radiations within extant groups were offset by reduced richness within groups that are now relict or extinct.

KW - entomology

KW - evolution

KW - fossil record

KW - Biodiversity

U2 - 10.1098/rspb.2015.2476

DO - 10.1098/rspb.2015.2476

M3 - Article

SN - 0962-8452

VL - 283

JO - Proceedings of the Royal Society B

JF - Proceedings of the Royal Society B

M1 - 20152476

ER -