The significance of software testing in development cycles lies in its ability to ensure quality and functionality in software products. Rigorous testing identifies defects or vulnerabilities before deployment, reducing the risk of failures and enhancing user experience. It encompasses various methodologies, including unit testing, integration testing, and user acceptance testing, each serving to validate different aspects of the software. Effective testing contributes to long-term cost savings, as it prevents costly post-release fixes and builds customer trust in the reliability of the product.