OBSERVATION A. Developmental Stages Of Housefly B. Developmental Stages Of Cockroach
Insects constitute the largest class of animals representing over 7,50,000 species. They are the most successful land invertebrates, and the only major competitors with humans for dominance in the world. Today, the life of every human being is affected by insects in one way or the other. Quit a number of insect varieties are closely connected with some of our diseases like malaria, cholera, plague, etc. and with our day to day life. Housefly (Musca nebula) and Cockraoch (Periplanta americana) are two such insects which effect the human life the most.
Houseflies have been pursuing mankind throughout all of recorded history, and probably from the time man emerged from his caves and began to walk erect Houseflies are cosmopolitan in distribution and are intimately associated with human life. Hence, they are found in all places of human dwelling. They remain active in all seasons except winters. They neither bite nor sting us, yet we hate them for their insanitory habbit.
Houseflies spread a number of communicable diseases like a cholera, typhoid, dysentery, etc. Indeed Flies are probably responsible for more deaths among humans then any perceived atrocities we may have misguidedly thrust upon them.
Cockroaches are also cosmopolitan in distribution and are found in such places of human dwellings, where darkness, warmth, dampness, and plenty of organic debris are available. Thus, one can easily find these hidden in our kitchens, sewers, godowns, railway compartments, ship, etc.
Cockroaches are nocturnal and omnivorous. They come out of their hiding places during the night in search of food. Cockroaches harm us by chewing our clothes, books, and leather wares when normal food in scanty.
COMMON HOUSEFLY (Musca nebula)
COCKRAOCH (Periplanta americana )
EXPERIMENT AIM: Keeping in view the huge impact that these insects have on lives of humans, the study of the developmental stages of the insects Housefly and Cockraoch have been selected for this project.
MATERIALS REQUIRED: Preserved specimens of different developmental stages of housefly/cockroach, notebook, pen, etc.
EXPERIMENTAL PROCEDURE: Get the preserved specimen of different developmental stages of housefly/cockroach and observe the stages carefully. Note down your observations in the notebook.
Body structure of Housefly
Life history of a Housefly
Housefly has grey body of 1. ADULT HOUSEFLY. about 6-7 mm long. The body is divided into head, thorax and abdomen: Head. Head is ovoid with two large, lateral compound eyes. Ommatidia is the unit of compound eye. In the centre of head three oscelli or simple eyes are present. In front of the head are two small, sensitive antennae.
Mouth parts. The proboscis(mouth0 is made up of three parts :
(1) (2) (3)
Rostrum Raustellum Oral disc (sucker)
For feeding, the raustellum forms food channel. This pierces into the food and sucks it into the alimentary canal.
Thorax: It is divided into three parts :
(1)Prothorax (2)Mesothorax (3)Metathorax Three pairs of legs arise from the segements of thorax. Each has five joints – (a) Coxa, (b) Trochanter, (c) Femur. (4) Tibia and (5) Tarsus. The mesothorax contains a pair of wings. They are transparent and have supporting veins. Metathorax contains halters, the vestigial wings. Abdomen: Female has five visible segments in the abdomen with five pairs of spiracles present on the lateral side. The male has sixth and seventh vestigial segment also with two pairs of spiracles on them. Fine hair are presen all over the abdomen. In females 6-9 segments form the ovipositor involved in reproduction.
2. EGGS. Egs are cylindrical, white, about, 1 mm long. Female lays about 120-150 eggs at a time. These
hatch out between 8 to 24 hours, depending on the temperature.
3. LARVA. The larva (maggot) is creamy, soft, wriggling worm-like. The body is made up of 12 segments and a distinct head, covered by cuticle. The head consists of maxilla, mandibles in pairs and a labium. The first and last segments have spiracles. The larva remains embedded inside the organic matter. It moults twice within 6-8 days to grow in size. The full grown larva is 12 mm long. 4. PUPA. The imago breaks the purium and emerges out. It is a weak small fly. It beomes active within few hours. The imago starts laying egs within two weeks.
Body Structure of Cockroach
Life History of Cockroach
You're Reading a Preview Unlock full access with a free trial.
Download With Free Trial
3. NYMPH: Inside the ootheca the eggs develop into the young one called nymphs. The ootheca wall is broken in about 7-8 days and young nymphs emerge out of it.
A nymph is small, light broen creature like the adult cockroach. However, I lacks wings and has immature gonads. The body is covered by chitin which gradually hardens and prevents growth of nymph. Each nymph undergoes 6 to 7 mounting to develop into an adult cockroach.
Comprehensive Laboratory Manual in Biology for CBSE Class 12 by Dr.J.P.Sharma.