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, knowledges of wild bees and apoid wasps’ community dynamics have gained interest in urban ecology focusing on the availability of floral resources in cities. Although understudied, the urban environment impacts the conditions of their nesting sites. Recent observations in the Brussels-Capital Region (Belgium) showed that urban pavements can be a novel nesting opportunity for Hymenoptera ground-nesting species such as wild bees and apoid wasps. Here, using citizen science, we investigated the richness of ground-nesting species living under urban pavements, the preferences of the sidewalk joint size related to ground-nesting species size and for sidewalk type or for soils texture under the pavements on the nesting site selection. A total of 22 species belonging to 10 Hymenoptera families of wild bees and digger wasps with their associated kleptoparasites were identified on 89 sites in Brussels. Sandstone setts or concrete slabs with an unbound joint size around 1 cm were found to be best suitable urban pavements for the ground-nesting species. The soil texture under the pavement was highly sandy among our samples. Finally, we also suggest engineering management guidelines to support bee and wasp species nesting under urban pavement in highly urbanized areas. Such observations pave the way for much research in the field of urban ecology to conceive multifunctional pavement promoting biodiversity.

They live under our streets: ant nests (Hymenoptera, Formicidae) in urban pavements

“…This sampling method allows for a larger geographical scope due to the time saved at each site and will give a better chance to find rare species. The locations from the dataset of Noël et al (2021) were used as a basis for the search for nests in order to cover as much territory as possible with a high probability of observing ants. An anthill was located on a pavement, either thanks to the sand mound between two paving stones or thanks to an ant followed to its anthill (Fig.…”

“…Recent studies focusing on the insect biodiversity of urban areas revealed the presence of several Hymenoptera species which can nest under urban pavements. These studies focused mainly on the nesting ecology of solitary bees and digger wasps, but also recorded some ant species ( Noël et al 2021 , Weber 2022 ).…”

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.…”

Inventaire de la faune apiforme (Hymenoptera, Apoidea) des quartiers Myosotis et Engeland à Uccle (Bruxelles, Belgique)

“…De plus, une forte concentration de nids a Entomologie Faunistique -Faunistic Entomology 2022-75 pu être mise en évidence dans la rue Achille Reisdorff du quartier Myosotis (Figure 4 et 5). Cette espèce a également la particularité de nicher à travers le joint de certains vieux trottoirs bruxellois (Noël et al, 2021). Cette bourgade était composée en majorité de nids de D. hirtipes, mais également de nids d'Halictus scabiosae, même si pour cette dernière, nous avons des occurrences dans le nouveau quartier Engeland.…”