Biology and behaviour of the silkworms

Transcription

1 Biology and behaviour of the silkworms Małgorzata Łochyńska Silkworms Breeding and Mulberry Cultivation Laboratory Institute of Natural Fibres and Medicinal Plants Wojska Polskiego 71B Poznań POLAND

2 Mulberry silkworm (Bombyx mori L.) Inseminated eggs. Uninseminated or just laid eggs. The egg of mulberry silkworm is oval, 1,5 mm in diameter and has a distinct hollow in the centre. There are about eggs in 1 gram.

3 Mulberry silkworm (Bombyx mori L.) In spring the caterpillars hatch from the eggs. They are 3 mm long. They start eating at once. After days the caterpillars become mature, 8-10 cm long.

4 Mulberry silkworm (Bombyx mori L.) During the caterpillars live, there are 4 moults after 4-7 days.

5 Mulberry silkworm (Bombyx mori L.) During the moult, the caterpillars stick to leaves with silk fibres and rise their heads, where they have a characteristic triangle of snapped epidermis.

6 Mulberry silkworm (Bombyx mori L.) The caterpillar comes out from the old epidermis, called indusium, which was sticked to leaves.

7 Mulberry silkworm (Bombyx mori L.) The caterpillar s epidermis has a very various pigmentation: white, black, speckled or without pigments. It is a feature of variety.

8 Mulberry silkworm (Bombyx mori L.)

9 Mulberry silkworm (Bombyx mori L.)

10 Mulberry silkworm (Bombyx mori L.) After days the caterpillars lose their appetite, they become yellow and the epidermises are transparent. That means, that they are ready to spin their flosses.

11 Mulberry silkworm (Bombyx mori L.) Just before spinning, we put the wood ladders, on which the caterpillars spin their flosses.

12 Mulberry silkworm (Bombyx mori L.)

13 Mulberry silkworm (Bombyx mori L.) A cocoon is a floss with a caterpillar, chrysalis or butterfly inside and the epidermis after the last moult.

14 Mulberry silkworm (Bombyx mori L.) Two salivaries, spinnerets, produce the silk fibre. They are 5 times longer than the caterpillar s body.

15 Mulberry silkworm (Bombyx mori L.)

16 Mulberry silkworm (Bombyx mori L.) Two single silk fibres (from two salivaries) are sticked in one double fibre.

17 Mulberry silkworm (Bombyx mori L.) The silk fibre is made from the white, unsoluble in water fibroine. Liquid fibroine get harden under the activity of oxygen. This proteine is covered with a yellow-coloured sericine (proteine glue).

18 Mulberry silkworm (Bombyx mori L.) During spinning the floss, the caterpillar sticks the silk fibre on the edge of the wood ladder. First it makes a dense net, called a floss, and then hangs the cocoon on it.

19 Mulberry silkworm (Bombyx mori L.) One caterpillar can produce the silk fibre, which is m long.

20 Mulberry silkworm (Bombyx mori L.) The caterpillar transforms into the chrysalis inside the cocoon and it undergoes a complete metamorphosis. After 2-3 weeks, the chrysalis transforms into a white butterfly.

21 Mulberry silkworm (Bombyx mori L.) The butterfly melts the top of the cocoon and goes out. It lives days. The female has bubble aromatic salivaries, which produce an aroma, that attracts a male. The wing span of this moth reaches 4 cm but it has no ability to fly.

22 Mulberry silkworm (Bombyx mori L.) The butterflies make a pair at once and start copulation.

23 Mulberry silkworm (Bombyx mori L.) After copulation, a female lays about 500 eggs in 2-4 days. One female can lay eggs. After winter, a new generation of caterpillars hatches from these eggs.

24 Mulberry silkworm (Bombyx mori L.)

25 The egg of the oak silkmoth is 5 mm in diameter. There is about 120 eggs in 1 gram.

26 After 8-14 days, the black and dense haired caterpillars hatch from the eggs.

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29 After 5-6 days, the caterpillars undergo the first moult and become yellow.

30 There are 4 moults during the caterpillar s live.

31 The moult lasts 2 days. At this time, the caterpillars freeze and do not eat.

32 The caterpillars just before and after the second moult.

33 The caterpillars before and after the third moult.

34 The caterpillars are covered with sparse and thorny hairs.

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37 Frightened caterpillars freeze and their hair stands on end.

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39 The caterpillars eat the leaves and small branches of oak and birch.

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41 After days from the hatch, the caterpillars grow to 15 cm. They become mature and spin the flosses.

42 The cocoons are sticked to the branches.

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44 The cocoons of oak silkmoth are very irregular. They have holes, loops and weaved leaves and branches.

45 The cocoons are white- or beige-coloured.

46 The cocoons of oak silkmoth contain less silk fibre than the cocoons of mulberry silkworm. However oak fibre is stronger and more resistant to acid and alkali activity.

47 Oak fibre is 3-4 times thicker than mulberry fibre.

48 Oak silkmoth spends winter as the chrysalis in the cocoon. Even when the teperature drops to 20 o C, the chrysalises are safe.

49 Transformation of oak silkmoth s caterpillar into the chrysalis lasts 7-9 days.

50 After 2-3 weeks, the butterflies melt the cocoons and go out.

51 The wing span of a butterfly reaches 15 cm. Unlike mulberry silkworm, this moth has the ability to fly.

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55 The butterflies make a pair and start copulation.

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57 After hours, a female lays eggs.

58 After 8-10 days, an autumn generation of black caterpillars hatches from the eggs. The oak silkmoth species gives two generation per year.

59 Mulberry silkworm (Bombyx mori L.) and oak silkmoth (Anthereae pernyi G.) The chrysalis and cocoon of mulberry silkworm and oak silkmoth

60 Mulberry silkworm (Bombyx mori L.) and oak silkmoth (Anthereae pernyi G.)

61 Mulberry silkworm (Bombyx mori L.) and oak silkmoth (Anthereae pernyi G.) The cocoons, from the mulberry silkworms breeding at INF&MP, will be used in: The cosmetics industry The textile industry The production of wear (scarves, ties) The production of surgical threads.