Trehalose in insect hemolymph serves as which of the following in contrast to vertebrate glucose?

• A. It acts as a protectant against extreme environmental conditions
• B. It acts as a primary energy source for rapid muscle activity
• C. It signals molt progression
• D. It is stored as a structural component of the cuticle

Answer: (C)

In insects, trehalose in the hemolymph is the main circulating sugar, supplying energy and linking metabolism to development. What makes trehalose especially interesting is that its levels influence how the insect’s endocrine system coordinates growth and developmental transitions. In particular, trehalose status can modulate insulin-like signaling, which interacts with the molting hormone system (ecdysteroids and juvenile hormone) to control when a molt proceeds. So trehalose functions beyond simply fueling tissues; it acts as a signal that helps regulate molt progression. That’s why this option best captures the distinctive role of trehalose in insect physiology.

Note: trehalose is not stored as a structural component of the cuticle, and while it can contribute to stress protection and fuel flight muscles, the question emphasizes its signaling role in development, which is the strongest distinctive concept.