Why do Jain ascetics avoid eating after dark?

Jain ascetics avoid eating after dark primarily to uphold the principle of nonviolence (ahimsa), which is the foundational ethical standard of Jainism.123

By refraining from consuming meals at night, an ascetic minimizes the risk of inadvertently harming small insects or other life-forms that might be attracted to the food in the dark. This practice is a specific application of the "great vows" (mahavratas) taken by monks and nuns, which require the utmost care to prevent injury to any living soul (jiva), whether knowingly or unknowingly. Because Jainism teaches that even unintentional harm can result in the accumulation of karma—a substance that keeps the soul trapped in the cycle of rebirth—such dietary restrictions are essential for maintaining spiritual purity and adhering to the path of non-injury.425