Answer :

Final answer:

Cheyletiella mites are ectoparasites that remain on their hosts by feeding on skin cells and other secretions, and their survival depends on the host's availability and co-evolutionary mechanisms to evade the immune system.

Explanation:

Cheyletiella mites are surface-dwelling parasites that remain on their hosts by feeding on skin cells, blood, or secretions. These ectoparasites are adapted to live on the warm-blooded vertebrate host for at least part of their life cycle, relying on the host for the necessary habitat and resources to survive. Environmental factors, such as the availability of the host and the interaction with the host, are critical in maintaining parasite populations. Moreover, cheyletiella mites have evolved mechanisms to effectively adhere to their host's skin, ensuring they remain attached while feeding and during their development. Factors such as co-evolution with the host and the ability to evade the host's immune system allow these mites to persist on the host and continue their life cycle.