Insect phenological lability is key for determining which species will adapt under environmental change. However, little is known about when adult insect activity terminates, and overall activity duration. We used community-science and museum specimen data to investigate the effects of climate and urbanization on timing of adult insect activity for 101 species varying in life history traits. We found detritivores and species with aquatic larval stages extend activity periods most rapidly in response to increasing regional temperature. Conversely, species with subterranean larval stages have relatively constant durations regardless of regional temperature. Multivoltine and univoltine species both extended their period of adult activity similarly in warmer conditions. Longer adult durations may represent a general response to warming, but voltinism data in subtropical environments is likely underreported. This effort provides a framework to address drivers of adult insect phenology at continental scales, and a basis for predicting species response to environmental change.

Study of species’ ecological niches through evolutionary history can elucidate speciation mechanisms, yet current comparative phylogenetic methods consistently overestimate niche evolution. Here we propose a method by which to characterize species’ fundamental ecological niches for comparative phylogenetic analysis using a bin-based approach that incorporates uncertainty in niche estimates. Simulation analysis using a traditional characterization method (median value calculated from species’ known occurrences) estimated a significantly higher rate of niche evolution than using our proposed method, and differences in rate estimates were consistent regardless of the number of simulated taxa in a phylogeny. We also demonstrate how to perform ancestral state reconstructions under the new coding system; reconstructions are performed for each bin individually, and ancestral fundamental niches inferred by smoothing each node’s reconstructions across all bins. Finally, we provide a worked empirical example of our method, investigating ecological niche evolution in 34 species of New World orioles (Icterus spp.). Ecological niches were generally conserved in the group, and only a few lineages appear to have experienced niche reduction and specialization.