Insect ecology and conservation in urban areas: An overview of knowledge and needs

1. Urban expansion across the globe profoundly impacts local biodiversity. The growing body of urban ecology research on animals has largely focused on mammals and birds, whereas knowledge of insect ecology and conservation in urban areas remains limited. 2. To anchor this Special Issue (SI), we have taken a broad approach to editorial and conducted a structured literature search to set the scene. We provide here an overview of existing literature reviews on urban insect ecology and conservation, indicate where the articles included in this SI contribute to developing our understanding and point to priority areas for further investigation. 3. Key themes in the growing literature (at individual, species, and/or community level) include the influence of habitat quality, quantity and land use type on insect diversity; the impacts of anthropogenic pollution (for instance, heat, noise, light and chemicals); habitat connectivity and changes in habitat structure and impacts of urban density on genetic diversity. Insect diversity and abundance broadly decline with urban density and loss of habitat. Beyond this, variation in responses of different taxa, or in different regions, and methodological limitations of individual studies make it challenging to identify general patterns. 4. Insect ecology and conservation research in urban environments should focus on applying ecological theory to understand variation in diversity patterns; investigating interactions between climate change and urban contexts; identifying impacts of novel environments on insect biodiversity; addressing methodological limitations and harmonising methodological approaches; and exploring the influence of social and historical factors on urban insect biodiversity. Insect conservation must also consider research into how best to communicate the value of urban insects to urban humans.