Dicladispa armigera facts for kids
Quick facts for kids Dicladispa armigera |
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| Dicladispa armigera specimen in Java | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Family: | Chrysomelidae |
| Subfamily: | Cassidinae |
| Genus: | Dicladispa |
| Species: |
D. armigera
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| Binomial name | |
| Dicladispa armigera (Olivier, 1808)
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| Synonyms | |
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Dicladispa armigera is a type of leaf beetle found in Southeast Asia. It's often called the "rice hispa". These beetles are known as a serious pest because they cause a lot of damage to crops in many countries. For every male rice hispa, there are usually about 1.26 to 1.46 females.
Contents
Life Cycle of the Rice Hispa
The rice hispa goes through several stages as it grows, just like many other insects.
Eggs
Female rice hispa beetles usually lay their tiny eggs on the underside of leaves. Sometimes, they also lay them on the top side. The eggs are very small and covered in a dark substance. Each egg is laid by itself. A female beetle can lay between 18 and 101 eggs in her lifetime, with about 55 eggs on average. The eggs hatch in about four days.
Larvae
When the eggs hatch, tiny larvae emerge. They are about 2.4 millimeters long, flat, and pale yellow. These larvae dig into the leaf, eating the green parts inside. They leave only the top and bottom layers of the leaf. This feeding often leaves discolored patterns on the leaf. The larvae stay and grow inside the leaf. They also turn into pupae there. A fully grown larva is about 5.5 millimeters long, flat, and dull pale yellow. The larval stage lasts for 7 to 12 days. After this, they change into pupae.
Pupae
D. armigera pupae are flat, brown, and about 4.9 millimeters long. The pupal stage lasts for about 4 days. During this time, the insect transforms into its adult form.
Adults
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Finally, the adult beetle, called an imago, comes out. It cuts its way out of the leaf where it grew. The adult beetle is about 5 millimeters long. It is bluish-black and has a spiny body. Female adults usually live for about 24 days, and males live for about 16 days. Some beetles have lived for as long as 90 days. Adult rice hispas have long, sharp spines on their body and wing covers.
Where Rice Hispas Live
Dicladispa armigera is found in many countries. It is very common in Bangladesh, India, and Laos. It is also present in other countries, but not as widespread. These include Bhutan, Cambodia, China, Indonesia, Iran, Korea, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Taiwan, Thailand, Vietnam, and Papua New Guinea.
How Rice Hispas Reproduce
These beetles can have many babies quickly. This helps them spread and become a problem. Adult beetles mate for the first time after 3 to 7 days. Mating is a careful process that takes about an hour.
How Rice Hispas Affect Humans
D. armigera causes a lot of damage to important crops. They especially target rice, maize (corn), and other grasses. Young plants are more easily damaged by these pests. Farmers want to reduce the number of rice hispas to get more crops. There are two main ways to control their populations: using natural enemies (biological control) or using special sprays (chemical control). Sometimes, people also remove them by hand.
Biological Control
Scientists have looked into using other species to control the rice hispa. For example, tiny wasps like Trichigramma zahiri and Neochrysocharis sp. lay their eggs inside the rice hispa's eggs or larvae. The wasp larvae then eat the rice hispa from the inside. Another wasp, Scutibracon hispae, attacks the larvae and pupae. These wasps are natural enemies of the rice hispa.
A special fungus called white muscardine fungus (Beauveria bassiana) has also been tested. When the fungus spores land on the beetle, they grow and enter its body. The fungus then uses the beetle's body for food. In tests, this fungus helped reduce the number of rice hispas. Adult beetles died 5 to 6 days after getting infected. The fungus would then cover their bodies. Infected eggs would have a white powdery mass around them. Infected larvae became thinner. Infected pupae became smaller and deformed.
Chemical Control
Different types of sprays have been tested on D. armigera. Some natural sprays, like Neem oil, have been very good at reducing rice hispa numbers by up to 96%. Regular pesticides are also very effective. They can reduce rice hispa populations by up to 100% in rice fields.
