Wooded streets, but not streetlight dimming, favour bat activity in a temperate urban setting

Data availability: The data used as input in our statistical tests is available from Figshare - https://figshare.com/s/31c0c425512f6de67df0.Copyright © The Author(s) 2023. Urbanization damages biodiversity, reducing people's connection to nature and negatively impacting the survivability of local species. However, with small adjustments, the damage could be mitigated. In temperate regions, several bat species inhabit urban areas, and with urbanization set to increase, adapting urban areas to improve their suitability for bats is imperative. Therefore, we investigated if wooded streets and streetlight dimming in an urban setting influenced bat activity. Static bat detectors were used to compare wooded versus non-wooded, and bright versus dim streets in Leicester, UK, on predominantly residential streets. The collected calls were quantified into bat activity (passes per night). Six species were identified, but the common pipistrelle (Pipistrellus pipistrellus) was dominant, making up 94.1% of all calls, so it was the sole species included in the statistical model. Wooded streets had significantly higher bat activity than non-wooded streets, but bright and dim streets were not significantly different. The results suggest that wooded streets were being used as green corridors, with common pipistrelles possibly following them to conceal themselves from predators, such as the tawny owl, and the proliferation of wooded streets in urban areas could allow the formation of better-connected populations. Streetlight dimming did not affect bat activity, but no light-averse bats were detected, likely because even the most dimmed streets deterred them despite street lighting increasing food availability by attracting insects. Therefore, an alternate solution, such as part-night lighting, may be required to increase the suitability of urban areas to light-averse species

Do cave orb spiders show unique behavioural adaptations to subterranean life? A review of the evidence

Interest for subterranean biology has risen sharply in recent years due to the simplicity of the cave environment. However, most studies have focussed on morphology with few studies looking at behaviour. The cave orb spiders show some unique behavioural adaptations compared to other orb spiders, including rudimentary orb webs, off-web foraging and a complex life cycle with a surface phase. Here, we compare these behavioural adaptations in the European Meta menardi and Meta bourneti to similar behaviours in surface-dwelling orb spiders. We find that current data suggest (1) an extreme reduction in the number of frame threads, (2) evidence of capturing non-flying prey, but not necessarily evidence for off-web foraging and (3) dispersal through a surface-dwelling life stage, but with data lacking on the role of ballooning and their return to caves. We conclude that Meta spiders have potential as model organisms for studies on behavioural adaptations and flexibility

Do cave orb spiders show unique behavioural adaptations to subterranean life? A review of the evidence

Interest for subterranean biology has risen sharply in recent years due to the simplicity of the cave environment. However, most studies have focussed on morphology with few studies looking at behaviour. The cave orb spiders show some unique behavioural adaptations compared to other orb spiders, including rudimentary orb webs, off-web foraging and a complex life cycle with a surface phase. Here, we compare these behavioural adaptations in the European Meta menardi and Meta bourneti to similar behaviours in surface-dwelling orb spiders. We find that current data suggest (1) an extreme reduction in the number of frame threads, (2) evidence of capturing non-flying prey, but not necessarily evidence for off-web foraging and (3) dispersal through a surface-dwelling life stage, but with data lacking on the role of ballooning and their return to caves. We conclude that Meta spiders have potential as model organisms for studies on behavioural adaptations and flexibility

The Effect of Wind Exposure on the Web Characteristics of a Tetragnathid Orb Spider

Studies on spiders in their natural habitats are necessary for determining the full range of plasticity in their web-building behaviour. Plasticity in web design is hypothesised to be important for spiders building in habitats where environmental conditions cause considerable web damage. Here we compared web characteristics of the orb spider Metellina mengei (Araneae, Tetragnathidae) in two different forest habitats differing in their wind exposure. We found a notable lack of differences in web geometry, orientation and inclination between webs built along an exposed forest edge and those built inside the forest, despite marked differences in wind speed. This suggests that M. mengei did not exhibit web- building plasticity in response to wind in the field, contrasting with the findings of laboratory studies on other species of orb spiders. Instead, differences in prey capture and wind damage trade-offs between habitats may provide an explanation for our results, indicating that different species employ different strategies to cope with environmental constraints

Functional convergence underground? : The scale-dependency of community assembly processes in European cave spiders

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