Nest aggregations of wild bees and apoid wasps in urban pavements: A ‘street life’ to be promoted in urban planning

Abstract

In the last 10 years, the interest in nature‐based solutions and ecosystem services like pollination has increased profoundly and with it the need to gather knowledge about wild bees and apoid wasp community dynamics, especially in urban ecosystems. Research on how the urban environment impacts the conditions of nesting sites is relatively scarce. Recent observations in the Brussels‐Capital Region (BCR; Belgium) show that urban pavements can provide alternative nesting opportunities for ground‐nesting Hymenoptera, such as wild bees and apoid wasps. Here, using a citizen science approach, we investigated the richness of ground‐nesting species living under urban pavements, as well as their preferences for sidewalk characteristics. A total of 22 species belonging to 10 families of wild bees, digger wasps and their associated cleptoparasites were identified at 89 sites in the BCR (Belgium). Sandstone setts or concrete slabs, with an unbound joint size of around 10 mm, were found to be the best suitable urban pavements for the ground‐nesting species. The soil texture under the pavement contained mainly sandy particles. We propose management guidelines to support bee and wasp species nesting under urban pavement in highly urbanised areas. Our observations pave the way for further research in the field of urban ecology and highlight the potential of multifunctional pavement designs that promote not only climate adaptation but also biodiversity.

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

“…Lessons from metapopulation ecology and a better understanding of patch quality for specific taxa will be critical to raising urban insect diversity and conserving this as a stable ecosystem component (e.g., Azhar et al, 2024;Liao & Lin, 2024). There are pathways to understanding patch improvement, but above this, integrating connectivity and opportunity for insects in urban areas more broadly and by design will contribute further (e.g., Noël et al, 2024) as will translocations to restore extirpated diversity (e.g., Yagui et al, 2024).…”

“…The ability of some invertebrates to adapt to these is documented, including green roofs (Wang et al, 2022), golf courses and lawns (Colding & Folke, 2009) and abandoned or waste lands (McKinney, 2021). Successful insect use of these habitats, such as ornamental garden ponds (Hill et al, 2024) or urban pavements (Noël et al, 2024), may be influenced by context‐specific environmental, management and social factors. Some studied habitats can be locally specific to countries, regions or urban typologies and may be inherently tied to local social and political history.…”

Ecological Speciation without Morphological Differentiation? A New Cryptic Species of Diodontus Curtis (Hymenoptera, Pemphredonidae) from the Centre of Europe

“…Females of this genus dig unicellular or multicellular tunnel nests primarily in clay or sand, provisioning them with Aphididae (Hemiptera) as larval food [20,21]. Apoid wasps, including Pemphredonidae, fulfil ecosystem services of biological control (as important natural enemies of herbivorous insects) and to a lesser extent, of pollination [20,[22][23][24][25]. Most of them depend on specific natural or early-or latesuccessional habitats, and thus they may serve as ecological indicators of anthropogenic impact [26].…”