How do parasites differ from parasitoids that always kill their hosts?

The primary distinction between parasites and parasitoids lies in the fate of the host. While both organisms benefit at the expense of a host, parasitism is a relationship where the parasite does not necessarily kill the host organism. In contrast, parasitoidism is a specialized strategy in which the parasitoid always kills its host.1

Key differences include:

• Host Survival: Parasites often evolve to maintain the host's life to ensure their own continued access to nutrients or to facilitate transmission to new hosts. Parasitoids, typically insects such as wasps, develop on or within a single host individual and inevitably cause its death as they complete their larval development.2341
• Life Cycle Strategy: Parasites may have complex life cycles involving definitive and intermediate hosts, sometimes utilizing vectors for transmission. Parasitoids generally focus their entire developmental cycle on a single host, which serves as the sole food source for the developing larva.154

While some parasites can be highly virulent, their evolutionary success is often tied to the host's survival, whereas the death of the host is a fundamental requirement of the parasitoid life cycle.123