Urban insect bioarks of the 21st century

Insects exhibit divergent biodiversity responses to cities. Many urban populations are not at equilibrium: biodiversity decline or recovery from environmental perturbation is often still in progress. Substantial variation in urban biodiversity patterns suggests the need to understand its mechanistic basis. In addition, current urban infrastructure decisions might profoundly influence future biodiversity trends. Although many nature-based solutions to urban climate problems also support urban insect biodiversity, trade-offs are possible and should be avoided to maximize biodiversity–climate cobenefits. Because insects are coping with the dual threats of urbanization and climate change, there is an urgent need to design cities that facilitate persistence within the city footprint or facilitate compensatory responses to global climate change as species transit through the city footprint. •Insect biodiversity can increase, decrease, or be maintained across urban gradients.•Biological and methodological factors can influence biodiversity trends.•A mechanistic understanding of urban insect biodiversity enables forecasting.•Cities interact with global climate change and can be used as climate proxies.•Nature-based urban infrastructure can yield climate–insect biodiversity cobenefits.