Zoophagous parasites are organisms that feed on or derive nutrients from animals. In the context of entomology, this term specifically describes insects that act as parasites on larger animal hosts, such as lice, fleas, or certain types of flies that feed on livestock or wildlife.

Parasites are organisms that live on or inside a host, deriving nutrients at the host's expense. Trichogramma and Cotesia are well-known parasitoid wasps used in biological control, while fleas and horse flies are common ectoparasites that feed on vertebrate blood. All listed examples represent various parasitic life strategies.

The oriental rat flea, Xenopsylla cheopis, is the primary vector for Yersinia pestis, the bacterium that causes plague. The disease is zoonotic, typically circulating among small rodent populations. Humans become infected primarily through the bites of these fleas after they have fed on infected rodents. This transmission cycle is a classic example of vector-borne disease dynamics.

The domestic silk moth (Bombyx mori) is economically significant for silk production, and its larvae feed almost exclusively on the leaves of the mulberry tree (Morus species). Sericulture relies heavily on high-quality mulberry cultivation to ensure healthy larval development and high-grade silk yield. While some wild silkworms may feed on other plants, the commercial industry is centered on mulberry-fed silkworms.

Polyphagous parasites are organisms that exhibit a broad host range, meaning they can successfully parasitize many different species. This trait provides them with a significant ecological advantage, as they are not dependent on a single host species for survival or reproduction. In contrast, oligophagous parasites are restricted to a few host species, and monophagous parasites are limited to only one.

Heteroxenous parasites are those that must infect two or more different host species to complete their biological life cycle. This complex life cycle often involves intermediate hosts and a definitive host. In contrast, monoxenous parasites complete their entire life cycle within a single host species. Understanding these requirements is essential for developing effective control strategies for parasitic diseases in both livestock and crop production.

The ensign wasp (family Evaniidae) is a specialized parasitoid that targets the ootheca (egg case) of cockroaches. The female wasp locates the cockroach egg case and deposits her eggs inside it. Upon hatching, the wasp larva consumes the developing cockroach eggs within the case. This biological interaction makes the ensign wasp a natural control agent for cockroach populations in various environments.

A potential pest is often categorized as a secondary pest, which typically does not cause significant damage under normal conditions but may become problematic if environmental factors change or if primary pests are removed. While the term 'potential' implies future risk, 'secondary' describes its current status relative to the primary pest complex. Management of secondary pests is crucial to prevent them from escalating into major threats following the application of broad-spectrum insecticides.

Kala-azar, or visceral leishmaniasis, is a severe parasitic disease caused by the protozoan Leishmania donovani. The parasite is transmitted to humans through the bite of an infected female phlebotomine sand fly. These flies are small, nocturnal insects that thrive in tropical and subtropical regions. Controlling the sand fly population and using protective measures like insecticide-treated bed nets are primary strategies for preventing the transmission of this disease.

Lac is a natural resinous secretion produced by several species of lac insects. The resin content in these secretions is approximately 68%. The harvesting process involves collecting sticklac from the branches of host trees. Because the valuable dye and resin are both products of the insect's life cycle, the insects are often left within the harvested sticklac to ensure the quality and color of the final product.