What features distinguish arthropods in the class Acari from those in class Insecta?

The distinguishing features of arthropods in the class Acari, which includes ticks and mites, from those in class Insecta are primarily related to their anatomical structure. Acari have a unique body plan that consists of a lack of antennae, which is a significant difference when compared to insects, as insects possess one pair of antennae. Additionally, Acari are characterized by having two body regions: a fused cephalothorax and abdomen, which is quite different from the three distinct sections (head, thorax, and abdomen) seen in insects.

Moreover, Acari adults have four pairs of legs, while insects, as adults, have three pairs of legs. These features highlight the evolutionary adaptations and functional differences between these two classes of arthropods. Understanding these distinctions is important in the study of entomology and acarology, especially in pest control contexts where identifying the type of organism is crucial for effective management strategies.