Order thysanura (silver fish)

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1. Order thysanura (silver fish) Presented To: Dr. Shahzad Ali Presented By: Mujahid Hussain 2019-mphil-1385

2. Silver Fish ( Lepisma saccharina ) The name Thysanura , derived from the Greek " thysano -" meaning fringed and " ura " meaning tail, refers to the long, fringed filaments on the abdomen of silverfish. A  silverfish  ( Lepisma saccharina ) is a small, wingless insect in the order  Zygentoma  (formerly  Thysanura ). Its common name derives from the animal's silvery light grey colour, combined with the fish-like appearance of its movements. However, the scientific name ( L. saccharina ) indicates the silverfish's diet consists of carbohydrates such as sugar or starches.

3. Description Silverfish are nocturnal insects typically 13–25 mm (0.5–1.0 in) long. Their abdomens taper at the end, giving them a fish-like appearance. The newly hatched are whitish, but develop a greyish hue and metallic shine as they get older. They have two long cerci and one terminal filament at the tip of the abdomen between the cerci. They also have two small compound eyes. They have long antennae, and move in a wiggling motion. Silverfish typically live for two to eight years. They are largely oviparous, depositing their eggs in cracks and crevices out of sight. They may be six or more instars, and in tropics maturity is reached in less than a year while in temperate regions two or more years are required to complete a generation.

4. Scientific Classification Kingdom : Animalia Phylum : Arthropoda Sub-phylum : Hexapoda Class: Insecta Sub-class: Apterygota Order: Zygentoma Family: Lepismatidae Genus: Lepisma Species: L. saccharina

5. Order Thysanura ( Thysanurans , Bristletails, Silver Fish Moths, Slickers) Diagnostic Features Small, primitive, elongated, flattened, naked or scaly bodies. Biting mouth-parts, maxillae long. Antennae long and many-segmented. Compound eyes well developed, vestigial or absent. Ocelli present or absent. Legs: Coxae small, tarsi 3 or 4 segmented with two or three claws.

6. Habit & Habitat Almost world-wide in distribution. They are among the most primitive of insects. Usually white, grey, brown or otherwise pigmented to harmonize with their immediate surroundings in the ground. They are apterous in nature and entirely dependent upon crawling, running and jumping. The habitat of these insects are of quite variable in nature. Majority of species adapt damp places under leaves, debris, bark, in rotten wood, mosses, lichens, on stones, trunks of trees and nests of ants and termite.

7. Cont ……. They are both diurnal and nocturnal and usually omnivorous in their feeding habits. Most of them are vegetarians that eat dry and decaying vegetation, fungi, lichens, mosses and similar plant material. House-inhabiting forms feed on cereals, pastes, glues, paper as well as starched clothing and sized silk and rayons . They may rarely eat woolen goods and other animal products.

8. Morphology The body seems to be naked but in fact they are usually somewhat hairy or covered with overlapping metallic scales and look like miniature dragons. Head is wide and not condtricted behind, antennae 30 or more segmented, compound eyes large and prominent or vestigial or absent, ocelli are present in few forms. Mouth parts: mandibles slender, entire or in two parts, incisors and molar areas wide apart, maxillary palpi composed of 4 to 7 segments, labial palpi 3 segmented.

9. Cont ……. The thorax forms the widest region, legs similar, often with one or more movable styli and hind coxae, tarsi 3 or 4 segmented with paired claws. Abdomen composed of 10 complete segments and the 11 th segment often modified into median caudal filament. The cerci often of 50 or more segments arise from the 10 th segment.

10. Reproduction Before silverfish reproduce, they carry out a ritual involving three phases, which may last over half an hour. In the first phase, the male and female stand face to face, their quivering antennae touching, then repeatedly back off and return to this position. In the second phase, the male runs away and the female chases him. In the third phase, the male and female stand side by side and head to tail, with the male vibrating his tail against the female.  Finally, the male lays a spermatophore, a sperm capsule covered in gossamer, which the female takes into her body via her ovipositor to fertilize her eggs.

11. Cont …… The female lays groups of fewer than 60 eggs at once, deposited in small crevices. The eggs are oval-shaped, whitish, about 0.8 mm (0.031 in) long, and take between two weeks and two months to hatch. A silverfish usually lays fewer than 100 eggs in her lifetime. When the nymphs hatch, they are whitish in colour, and look like smaller adults. They may go through 17 to 66 moults in their lifetimes, sometimes 30 in a single year—many more than most insects.

12. Life Cycle

13. Economic Importance Domestic species such as silverfish and firebrats may cause extensive damage to household goods.  They often feed on wallpaper paste, bookbindings , and the starch sizing of some textiles.  Cardboard and other paper products may also be damaged.

14. IPM for Order Thysanura There are two methods for the control of silverfish. Physical Control Chemical Control

15. 1. Physical Control Dehumifying Vaccuming Removal of food Trapping Eliminating harborage sites Drying store articles

16. 2. Chemical Control Diatomaceous earth Borate-based insecticidal dust production Silica aerogel Residual insecticides