Read the following short passage and choose the best answer to the question below it. Passage: "Studies of urban bird populations have consistently shown that species diversity declines as levels of artificial light at night increase. Researchers have proposed several explanations for this pattern, including disruption of circadian rhythms, attraction of predators to lit areas, and reduction of available food sources. However, a 2022 meta-analysis suggested that the strongest predictor of reduced diversity is not light itself but the associated loss of insect prey, which is also drawn to artificial lighting and becomes more vulnerable to predation in illuminated zones." Question: What is the main point of the passage?