After cutting back shrubs, which pest can potentially see a population decrease?

Cutting back shrubs can lead to a decrease in the bee population primarily due to the impact on their habitat and food sources. Bees rely on flowers and blooming plants for nectar and pollen, which are essential for their foraging and reproductive activities. When shrubs are cut back, especially if it reduces flowering plants or native vegetation that they depend on, bees may find fewer resources available to them, leading to a decline in their numbers.

In contrast, the other pests listed—wasps, ants, and flies—may not experience the same type of direct impact from shrub cutting. Wasps may adapt to changes in their environment more readily, while ants often have various food sources and could even thrive in disturbed habitats. Flies, depending on the species, may not be significantly affected by the pruning of shrubs, as their life cycles and habitats can vary widely and are often less dependent on specific plant structures. Thus, the primary concern regarding the reduction of food availability for bees leads to the conclusion that they are the pest whose population may potentially decrease following the cutting back of shrubs.