What do we call parasites that live only part of their life cycle on the host animal?

The term used to describe parasites that live only part of their life cycle on the host animal is "transitory parasites." These parasites do not rely on their host for their entire life cycle; instead, they may spend only a portion of it on the host before moving on to other environments or life stages. This distinguishes them from parasites that depend on the host for survival throughout their entire life cycle.

Understanding this distinction is crucial in parasitology, as it affects how the parasites interact with their hosts and the ecological implications. For example, transitory parasites might be less harmful over time since they do not remain on their hosts indefinitely, allowing for the host to recover between infections.

In contrast, permanent parasites establish a long-term relationship with their hosts, obligate parasites must spend their entire life cycle on or in the host, and facultative parasites can thrive in both parasitic and free-living conditions, further highlighting the unique nature of transitory parasites. Each type of parasite has distinct characteristics and impacts on their hosts, which is essential knowledge for anyone studying parasitology or related fields.