EN65CH23_Wagner ARjats.cls December 19, 2019 12:24 Annual Review of Entomology Insect Declines in the Anthropocene David L. Wagner Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269, USA; email:
[email protected] Annu. Rev. Entomol. 2020. 65:457–80 Keywords First published as a Review in Advance on insect decline, agricultural intensi!cation, climate change, drought, October 14, 2019 precipitation extremes, bees, pollinator decline, vertebrate insectivores The Annual Review of Entomology is online at ento.annualreviews.org Abstract https://doi.org/10.1146/annurev-ento-011019- Insect declines are being reported worldwide for "ying, ground, and aquatic 025151 lineages. Most reports come from western and northern Europe, where the Copyright © 2020 by Annual Reviews. insect fauna is well-studied and there are considerable demographic data for All rights reserved many taxonomically disparate lineages. Additional cases of faunal losses have been noted from Asia, North America, the Arctic, the Neotropics, and else- where. While this review addresses both species loss and population declines, its emphasis is on the latter. Declines of abundant species can be especially worrisome, given that they anchor trophic interactions and shoulder many Access provided by 73.198.242.105 on 01/29/20. For personal use only. of the essential ecosystem services of their respective communities. A review of the factors believed to be responsible for observed collapses and those Annu. Rev. Entomol. 2020.65:457-480. Downloaded from www.annualreviews.org perceived to be especially threatening to insects form the core of this treat- ment. In addition to widely recognized threats to insect biodiversity, e.g., habitat destruction, agricultural intensi!cation (including pesticide use), cli- mate change, and invasive species, this assessment highlights a few less com- monly considered factors such as atmospheric nitri!cation from the burning of fossil fuels and the effects of droughts and changing precipitation patterns.