How does the life cycle of the meadow spittlebug proceed through the year?

The meadow spittlebug (Philaenus spumarius) follows a life cycle consisting of one generation per year. The progression through the year is as follows:12

• Late Summer: Adults mate and lay eggs on the stems or sheaths of host plants. These eggs remain on the plants throughout the winter.1
• Spring: The overwintering eggs hatch into larvae (nymphs).1
• Development: Over the next 4 to 6 weeks, the nymphs develop into adults. During this immature stage, they produce a protective, frothy substance known as spittle by mixing anal fluid with glandular secretions and introducing air bubbles.132
• Adulthood: Once the nymphs mature, they become adults, which do not produce spittle. These adults eventually begin the cycle again by producing eggs that will overwinter.13

Would you like to know more about how the spittle protects these insects from predators and environmental conditions?