What type of pine needles do pine sawfly caterpillars primarily feed on?

Pine sawfly caterpillars primarily feed on young pine needles, which are generally softer and more nutrient-rich than older needles. These younger growth patterns are often found at the tips of branches, where new foliage emerges in the spring. The preference for young needles makes sense for the caterpillars as they require higher nutrient content for growth and development, influencing their survival and population dynamics.

Older pine needles tend to be tougher, with a higher resin concentration, which can deter many insects from feeding on them. Although some insects may feed on older needles, pine sawfly caterpillars are adapted to exploit the tender, nutritious young needles to maximize their growth potential. This feeding behavior can lead to significant defoliation in pine trees, particularly in young stands where the growth is concentrated at the tips.