insectivore inclusive: Biological control and Insectivorous plants

An insectivore is a type of carnivore with a diet that consists chiefly of insects and similar small creatures.
An alternate term is entomophage, which also refers to the human practice of eating insects.
The first vertebrate insectivores were Amphibians. When they evolved, 400 million years ago, the first amphibians were piscivores, with numerous sharp conical teeth, much like a modern crocodile. The same tooth arrangement is however also suited for eating animals with exoskeletons, thus the ability to eat insects is an extension of piscivory.

Insectivorous plants are plants that derive some of their nutrients from trapping and consuming animals or protozoans. The benefit they derive from their catch varies considerably; in some species it might include a small part of their nutrient intake and in others it might be an indispensable source of nutrients. As a rule however, such animal food, however valuable it might be as a source of certain critically important minerals, is not the plants' major source of energy, which they generally derive mainly from photosynthesis.
Insectivorous plants might consume insects and other animal material trapped adventitiously, though most species to which such food represents an important part of their intake, are specifically, often spectacularly, adapted to attract and secure adequate supplies. Their prey animals typically, but not exclusively, comprise insects and other arthropods. Plants highly adapted to reliance on animal food use a variety of mechanisms to secure their prey, such as pitfalls, sticky surfaces, hair-trigger snaps, bladder-traps, entangling furriness, and lobster-pot trap mechanisms. Also known as carnivorous plants, they appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic bogs and rock outcroppings.
Insectivorous plants include the Venus flytrap, several types of pitcher plants, butterworts, sundews, bladderworts, the waterwheel plant, brocchinia and many members of the Bromeliaceae. The list is far from complete, and some plants, such as Roridula species, exploit the prey organisms mainly in a mutualistic relationship with other creatures, such as resident organisms that contribute to the digestion of prey. In particular animal prey organisms supply carnivorous plants with nitrogen, but they also are important sources of various other soluble minerals, such as potassium and trace elements that are in short supply in environments where the plants flourish. This gives them a decisive advantage over other plants, whereas in nutrient-rich soils they tend to be out-competed by plants adapted to aggressive growth where nutrient supplies are not the major constraints.
Technically these plants are not strictly insectivorous, as they consume any animal that they can secure and consume; the distinction is trivial however, because not many primarily insectivorous organisms exclusively consume insects. Most of those that do have such a restrictive diet, such as certain parasitoids and hunting wasps are specialised to exploit particular species, not insects in general. Indeed, much as large mantids and spiders will do, the larger varieties of pitcher plant have been known to consume vertebrates such as small rodents and lizards. Charles Darwin wrote the first well-known treatise on carnivorous plants in 1875.

Biological control is defined as the reduction of pest populations by natural enemies and typically involves an active human role. Natural enemies of insect pests, also known as biological control agents, include predators, parasitoids, and pathogens. Biological control agents of plant diseases are most often referred to as antagonists. Biological control agents of weeds include herbivores and plant pathogens. Predators, such as birds, lady beetles and lacewings, are mainly free-living species that consume a large number of prey during their whole lifetime. Parasitoids are species whose immature develops on or within a single insect host, ultimately killing or fatally infecting the host. Most have a very narrow host range. Many species of wasps and some flies are parasitoids. Pathogens are disease-causing organisms including bacteria, fungi, and viruses. They kill or debilitate their own host and are relatively specific. There are three basic types of biological control strategies; conservation, classical biological control, and augmentation