Why might these trees only secrete nectar on young leaves rather than larger more mature leaves?

Question

Quizplus · Accepted Answer

Young leaves near the apical meristem are actively growing and require more nutrients to support growth. Secreting nectar on these leaves could attract pollinators and ensure successful fertilization of the growing parts of the tree. Mature leaves would not require as much nutrient support for growth and, therefore, may not need to secrete nectar to attract pollinators.

Why Might These Trees Only Secrete Nectar on Young Leaves