Are cicadas, locusts, moths, and stick insects pests or beneficial insects?

Insects are extremely diverse in species and varied in form, belonging to the arthropods among invertebrates, and are the most numerous animal group on Earth. Common ones include cicadas, locusts, moths, stick insectsand others. Many people are unclear about whether these insects are pests or beneficial insects. Let us take a look together!

1. Cicada

The cicada is commonly known as the zhi liao (zhi liao) or jie luo zi. Cicadas usually live in temperate to tropical regions of the world, with a few distributed in desert areas. They are the general term for insects of the family Cicadidae, suborder Auchenorrhyncha, order Hemiptera, class Insecta. The nymphs live in the soil and belong to the hemimetabolous insects. The nymphs suck the roots of plants, and the adults feed on plant sap.

Are cicadas beneficial insects or pests?

Cicadas are pests. Throughout their life, cicadas are harmful to plants and are destroyers of trees. They insert their needle-like mouthparts beneath the head into the branches and trunks of trees, piercing and sucking plant sap to sustain life. After mating, the female cicada also uses its spear-shaped ovipositor to insert into the xylem of young tender branches to lay eggs. Each insertion makes a hole, and on a single branch many small holes are often made. After laying eggs, it uses its mouthparts to pierce a ring around the lower part of the branch through the cambium, so that the upper part of the branch cannot obtain water and nutrients and eventually dies. When the wind blows, the dead branch falls to the ground. The eggs hatch into nymphs, which burrow into the soil and begin a long underground life, feeding on the sap of tree roots underground. This lasts at least two or three years, or as many as seventeen years. Only after living long enough underground do they crawl out to the surface, then “the golden cicada sheds its shell”, and they emerge as adults.

How long do cicadas live?

Different species of cicadas have different life cycles. The life cycle of French cicadas is mostly 4 years, while in North America there are cicadas with a lifespan of up to 17 years. The lifespan of most cicadas in China is 3 to 7 years, of which nearly half are 5 years, and a few can live through 8 to 9 years.

What do cicadas eat?

The nymphs of cicadas live in the soil and use their piercing-sucking mouthparts to suck the sap from plant roots. They usually stay in the soil for several years or even more than ten years, such as 3 years, 5 years, and also 17 years. In summer, the adults sing in the trees and feed by using their needle-like mouthparts to suck tree sap.

2. Locust

Locusts are also known as grasshoppers, grasshoppers, and mai zha, among other names. They are the general term for animals of the family Acrididae, order Orthoptera, distributed in tropical and temperate grasslands and desert areas around the world. There are more than 10,000 species worldwide, and more than 1,000 species in China, among which the East Asian migratory locust has the widest distribution and causes the most serious damage in China.

Are locusts beneficial insects or pests?

Locusts are agricultural pests. Locusts are an important component of agricultural, forestry, and pastoral ecosystems. Many harmful locust species can cause varying degrees of damage to agriculture, forestry, and animal husbandry. There are already more than 10,000 species of locusts worldwide, among which about 300 species can cause harm to agriculture, forestry, and animal husbandry. Locusts can occur worldwide except in Antarctica and in areas north of 55° north latitude in Eurasia. The area where locusts occur year-round worldwide reaches 46.8 million square kilometers, and 1/8 of the global population is frequently affected by locust plagues.

3. Moth

Moths are the general term for insects closely related to butterflies. Both belong to the order Lepidoptera. When at rest, most spread their wings on both sides of the body. Their wings have eye-like patterns that can deter enemies. They are mostly active at night and like to gather in bright places, hence the folk saying “the moth flies into the flame and burns itself”.

Are moths beneficial insects or pests?

Moths are pests. The larvae of moths have chewing mouthparts and feed on plant leaves, making them important pests of agricultural and forestry crops, fruit trees, tea, vegetables, flowers, and more. Adults cannot chew food, but instead suck tree sap, nectar, and the like with a long mouthpart similar to a straw. Some species also form sheaths or spin silk webs. Some bore into plant tissues and cause damage, mining the leaf mesophyll and boring into stems. Some invade and damage buds, flowers, seeds, and other tissues, and can sometimes cause galls. Larvae living in the soil bite and eat plant roots, becoming important underground pests. Species that damage stored grain, goods, or hides are important storage pests. A small number of species are predatory, preying on aphids or scale insects, such as the ciliate blue butterfly, which is a natural enemy of the sugarcane woolly aphid.

4. Stick insect

Stick insects are medium-sized or large insects of the subclass Pterygota within the superorder Orthopterida. They are named for their slender bodies. They may be winged or wingless. Most have dark brown body coloration, while a few are green or dark green. They inhabit high mountains, dense forests, and environments with complex habitats. They have typical mimicry and protective coloration and are not easily found by enemies.

Are stick insects beneficial insects or pests?

Stick insects are pests. Stick insects live in forests or bamboo groves. They are phytophagous and can harm plants. They can be seen feeding both day and night, but most feed and are active in the evening. Especially in Oceania, several species of stick insects often occur in large numbers and feed on eucalyptus leaves. There are also reports in China of damage to oak trees causing disasters.

What natural enemies do stick insects have?

Cuckoo wasps

Cuckoo wasps are also known as cuckoo bees, red-tailed wasps, and other names. Most are distributed in parts of North China. Their method of laying eggs is peculiar. The cuckoo wasp lays its eggs inside the nests of bees and wasps or on the skin of other larvae. After the larvae hatch, they usually eat the food in the nest and even eat the small larvae of bees and wasps. Scientists call this phenomenon “borrowing a nest to lay eggs”.

Crows

Crows are birds of the genus Corvus, family Corvidae, order Passeriformes, class Aves. They are omnivorous. Many species like to eat carrion and do some harm to seedlings and grain. However, during the breeding period they mainly feed on small vertebrates, locusts, mole crickets, scarab beetles, and moth larvae, which is beneficial to agriculture. In addition, because they like carrion and peck at agricultural waste, they can eliminate pollution caused by animal carcasses and the like, playing a role in purifying the environment.

Drongos

Drongos are birds that inhabit tropical broad-leaved rainforests in mountainous areas. They are active in open grasslands in forests, beside open rivers in valleys, or in moist swampy areas. They mainly feed on insects such as locusts and grasshoppers, and also eat plant stamens and berries. They often perch for long periods at the tops of isolated tall trees, sometimes suddenly flying up rapidly to catch insects flying past in the air, or flying and weaving through dense trees.

Ants

Ants are a kind of insect with many species. More than 11,700 species are known worldwide, and more than 600 species have been confirmed within China. Their lifespans are very long. Worker ants can survive from a few weeks to 3 to 10 years, while queens can survive several years or even ten years. A single ant nest can grow in one place for several years or even more than ten years. It should be noted that termites are not ants.

Spiders

Spiders are the most abundant predatory animals in terrestrial ecosystems. They are the general term for all species in the order Araneae, class Arachnida, phylum Arthropoda. They are distributed worldwide except in Antarctica. Their role in maintaining the stability of agricultural and forestry ecosystems cannot be ignored. They mostly feed on insects, other spiders, and myriapods, and some spiders also feed on small animals.

Mantises

Mantises are terrestrial predatory insects (carnivorous). They are widely distributed around the world except in polar regions, with the richest species diversity in tropical areas. Any small species of insect can be preyed upon by mantises, especially flies, mosquitoes, locusts, and the eggs, larvae, exposed pupae, and adults of moths and butterflies, all of which are suitable prey for them. Even large insects such as cicadas and migratory locusts are also their prey.

Changeable lizard

The changeable lizard is a reptile of the genus Calotes, family Agamidae. It mostly inhabits tropical and subtropical regions and is commonly found under forests, in hillside grass, near graves, by riversides, along roadsides, and in grass or on tree trunks near residences. It has strong adaptability and is not affected by human activities. Its survival altitude range is 80 to 2,000 m. It mainly feeds on insects and small vertebrates, including rodents and other lizards.