Why do insects need a certain amount of heat for their development?

Insects require a specific amount of heat for their development because temperature plays a crucial role in metabolic processes, which are necessary for growth and transformation from one life stage to another. Insects undergo a life cycle that includes distinct phases such as egg, larva, pupa, and adult. Each of these phases has a certain temperature range that is optimal for the physiological processes involved in development.

Heat influences the rate of biochemical reactions; warmer temperatures generally accelerate these reactions, leading to faster development. As temperatures drop, these processes slow down, which can delay maturation and even affect survival rates. Thus, the correct understanding is that heat is essential for facilitating the transitions between developmental stages in insects, making option B the accurate choice.

Other choices, while also related to insect biology, do not directly address the necessity of heat for development. Assembling their physical structure and establishing territorial boundaries, although important behaviors and processes, do not primarily depend on temperature in the same critical way that developmental stages do. Attracting mates involves behavior influenced by various factors, including pheromones and visual cues rather than temperature alone.