Primary consumers play a vital role in food chains by acting as herbivores that feed on producers, such as plants. They convert the energy stored in plants through photosynthesis into forms that can be utilized by higher trophic levels. This process facilitates energy transfer within the ecosystem, enabling secondary consumers and higher-order predators to gain energy and nutrients. Additionally, primary consumers help regulate plant populations, contributing to biodiversity and maintaining ecological balance. Their interaction with producers is fundamental for the sustainability of ecosystems.