Final answer:
Ecdysones are steroids responsible for regulating the molting process in arthropods, with their activity influenced by the presence or absence of juvenile hormone (JH). These hormones control gene transcription and subsequent protein synthesis that governs molting and metamorphosis.
Step-by-step explanation:
Ecdysones are steroids that play a crucial role in the regulation of molting in arthropods. These steroidal hormones are triggered by another hormone known as juvenile hormone (JH) which, in its presence, promotes larva-to-larva molts. As the level of JH decreases in mature caterpillars, ecdysone promotes the transition from pupa to adult during the metamorphosis process.
Steroid hormones are also known to regulate gene transcription by affecting the synthesis of mRNA, which in turn modulates protein synthesis and therefore regulates specific cell processes. This regulatory function is essential across various species, with steroid hormones controlling different aspects of development and physiology such as sexual growth, reproductive cycling, and homeostasis, in addition to their role in arthropod metamorphosis.
It is important to note that insect growth regulators, which are a diverse group of substances, can affect insect development and interfere with the molting process, which is a critical stage for many pests, particularly in their larval forms.