What are the three parts of the shape of a silkworm?

The silkworm's body is divided into three parts: head, chest and abdomen, and consists of thirteen sections.

The head has a mouth and six pairs of monocles, and the chest has three pairs of feet with sharp ends (chest feet). There are four pairs of round meat feet (abdominal feet) and a pair of tail feet in the abdomen. Abdominal feet can help silkworms crawl around on mulberry leaves.

Silkworm is a deformed insect, the most common one is silkworm, also called silkworm, which is one of the economic insects that spin silk and cocoon on mulberry leaves. Silkworm originated in China, its development temperature is 7 ~ 40℃, and its suitable feeding temperature is 20 ~ 30℃. Silkworm babies feed on mulberry leaves After eating mulberry leaves continuously, the body turned white and began to peel after a period of time. When peeling, they don't eat or move like sleeping for about one day. This is called "dormancy".

Once skinned, it is the second instar larva. Even if it is peeled once, it will increase by one year, and the larvae will be peeled four times to become fifth instar larvae. After eating mulberry leaves for 8 days, they will become mature silkworms and start spinning and cocooning.

Extended data:

Insect families in the animal kingdom are huge and diverse, and their metamorphosis types are varied, mainly including the following five metamorphosis forms:

1, adding segment exception

For example, there are differences in body size and organ development between the larval and adult stages of pterodactyl, and the number of abdominal segments increases gradually from 9 to 12.

2. Exception table

For example, collembola, a subclass of wingless insects, has basically the same shape as adults when it is still a larva, but during its growth and development, its sexual organs gradually mature, the number of tentacles and tails increases, and its individual size also changes somewhat.

3. Primitive pervert

This metamorphosis only exists in winged insects of the order Mayflies. From larva to adult, it goes through the stage of sub-adult, which is short and in a static state.

4. Incomplete metamorphosis

The main feature of this metamorphosis is that the characteristics of insect adults gradually appear in the process of growth and development through three stages: egg stage, larva stage and adult stage.

5, completely abnormal

Insects that conform to this metamorphosis form are characterized by four stages: egg, larva, pupa and adult. Larvae and adult have great differences in external morphology and living habits. When larvae mature, they lose their form.

But the shape of pupa is basically close to that of adult. Such as LEPIDOPTERA moths and butterflies, larvae have no antennae and wings, and their mouthparts are chewing. After becoming an adult, all the larval forms disappear. Not only do they have wings to fly freely, but their mouthparts also become siphoned. Coleoptera, Diptera, Hymenoptera, Neuroptera, etc.

The larval morphology of some fully metamorphosed insects is also different at different ages, which is called metametamorphosis, such as beetles, scorpions, flies of Diptera and wasps of Hymenoptera. In a word, all the higher orders in winged subclass belong to the form of complete deformation.

Baidu encyclopedia _ insect metamorphosis