Cutting back shrubs in gardens limits the presence of which flying insect?

Cutting back shrubs in gardens primarily limits the presence of bees. This is because many bees rely on flowering plants and shrubs for nectar and pollen, which are essential for their survival and reproductive success. When shrubs are cut back, especially if done during the growing season, it can reduce the availability of flowers that provide food sources for these pollinators.

Moreover, certain bee species, particularly solitary bees, often nest in or around shrubbery. When shrubs are pruned or removed, their nesting sites can be disturbed, further impacting their populations in that area. By reducing the flowering potential and nesting opportunities, gardens with trimmed or sparse shrubs become less hospitable environments for bees, which could result in a decrease in their presence in those gardens.

The other insects listed, such as butterflies, moths, and flies, may not be as significantly affected by the pruning of shrubs. While they may also rely on floral resources, their relationship with shrub structures and their nesting behaviors can differ, making them less impacted by such gardening practices compared to bees.