What are natural enemy insects? An introduction to common natural enemy insects such as green lacewings
What are natural enemy insects, what characteristics do they have, and what do they mainly eat? Using natural enemy insects to control pests is a special control method that can reduce environmental pollution and maintain ecological balance. The mass rearing and use of natural enemy insects in China have achieved remarkable results. Now let us take a look at the introduction below.
Natural enemy insects are insects that parasitize or prey on other insects. They have long controlled the development and spread of pests in farmlands, forest areas and pastures.
Green lacewings belong to the order Neuroptera and have egg, larval, pupal and adult stages. There are 105 species on the mainland, and more than 200 species are known in Taiwan, China. Because green lacewings feed mainly on aphids, they are commonly known as aphid lions. When feeding, the larva pierces its pincer-like mouthparts into the prey's body and sucks out all the prey's body fluids, thereby killing the pest. The larva's back has many tubercles, on which the sucked-dry prey are placed as camouflage, making it look like bird feces; some species have green adults with slender wings and many wing veins, like lace, hence the English name ”green lacewing”.
The larvae can prey on red spider mites, aphids, whiteflies, scale insects, as well as the eggs and larvae of many kinds of pests, and they have a large appetite, move quickly and have strong predatory ability, making them a multifunctional commercial natural enemy insect. Indoors, larvae are reared on rice moth eggs, and adults are fed an artificial diet made by mixing yeast powder with honey. Female adults lay eggs at the tip of a silk secretion stalk about 0.5 cm long. In application, green lacewing eggs can be placed in rice fields, or larvae can be released directly onto crops. Adults mainly sip nectar and eat pollen. Mantises (mantid) belong to the order Mantodea and are gradual-metamorphosis insects among the incomplete-metamorphosis types. More than 1,500 species are known, and there are 17 species in Taiwan, China. Both the young stages and adults are carnivorous and prey only on moving food, and can catch butterflies and moths, flies or locusts. The head is triangular, with three simple eyes in the middle and well-developed compound eyes. It is the only insect whose head can turn backward 180 degrees. The pronotum and the coxae of the first pair of legs are also unusually long, and the second and third segments of the front legs bear spines and are specialized into sickle-shaped grasping legs. It often holds its front legs up high waiting for prey to come, as if praying, so it is also called the praying mantid (praying mantid).
The broad-bellied mantis has a pair of obvious white spots on its wings, and besides green, there are also brown individuals. Mantises lay their eggs inside an egg case formed from secretions, called an "piao xiao" (pronounced piao xiao, used in traditional Chinese medicine). More than a hundred eggs are arranged inside the egg case in four rows in a "人"-shaped pattern, and in nature they are often parasitized by parasitic wasps. Newly hatched young insects first shed their embryonic covering and need 7-8 molts before growing into adults, which takes about 70-80 days; if food is insufficient, it takes even longer. Females are larger than males, and during mating the male is slowly eaten by the female starting from the head, but this does not affect the mating result, because the nerves in the head do not control the male's sperm transfer. Mantises can be reared indoors, using housefly larvae bought from fishing tackle shops as food; newly hatched young mantises are fed small fruit flies. The rearing box must create a three-dimensional space for them to rest, otherwise cannibalism is severe. Providing sufficient water can help them live longer.
Hoverflies, also called hover flies, move about on leaves preying on aphids. They belong to the order Diptera, family Syrphidae (syrphidae), and are complete-metamorphosis insects. The larvae resemble maggots and are often found near places where aphids occur on tender shoots. Green-colored ones have a white stripe on the back, and there are also brown transparent larvae. Many species have adults colored like bees or wasps, and because they often fly among flowers, they are also called flower flies (flower flies), feeding on nectar.
The larvae of this group of insects vary greatly in habitat and appearance. Many species are beneficial insects that specialize in preying on aphids and can be used as natural enemy insects to control aphids. Some hoverfly larvae parasitize the nests of social insects, such as ant, termite or bee nests; there are also species that live in decaying plants or wood; the larvae of some species have a very long breathing tube at the end of the abdomen and live in extremely polluted freshwater.