SUBJECTIVE QUESTIONS OF HEXAPODA AND MYRIAPODA
- Describe evolutionary perspective of insects.
- What factors does responsible for the success of insects?
- Describe external body features of insects.
- Give evolution of fight in insects.
- Give mechanism of flight in different insects.
- Describe other forms of locomotion in insects.
- Write note on mouth parts of insects.
- How are gases exchanged in the insects?
- Give mechanism of respiration.
- Describe blood circulation in insects.
- Write note on thermoregulation in insects.
- Describe nervous system of insects.
- Write note on different sense organs in the insects,
- Write note on compound eye of insects.
- Discuss excretion in insects.
- Give different endocrine glands in insects.
- Write note on pheromones.
- Describe reproduction in insects.
- Give different types of metamorphosis in insects
- Write note on social insects.
- Give social behaviour in honey bees.
- Write note on different beneficial insects.
- Discuss different harmful insects.
- Give the evolution of arthropods.
1. What is thermoregulation?
Ans: Thermoregulation is the ability to maintain body temperatures at a level different from environmental temperatures.
2. Define an insect.
Ans: The arthropods with three pairs of wing, one pair of antennae and three pairs of legs are called insects.
3. Name the segments of thorax of insects.
Ans: Prothorax, mesothorax, and metathorax.
4. Name different structures preset in the abdomen of insects.
Ans: Lateral fold, Genital structures, Cerci and Gills.
5. What is Direct or Synchronous Flight?
Ans: In this case muscles move the wings directly. One group of muscles is present on the bases of the wings. They contract to produce a downward thrust. Second group of muscles is attached dorsally and ventrally on the exoskeleton. These muscles contract to produce an upward thrust.
6. What is indirect or asynchronous flight mechanism?
Ans: In this case a muscle does not move the wing directly. They only change the shape of the exoskeleton for both upward and downward wing strokes.
7. What is critical point of wing?
Ans: There is a critical point midway into the down stroke. This stored energy reaches a maximum at the critical point.
8. What are fibular flight muscles?
Ans: Indirect flight muscles are called fibular light muscles.
9. Name the mouth parts of insects.
Ans: Labrum, Mandible, Maxilla and Labium
10. What is the function of Mechanoreceptors?
Ans: Mechanoreceptors detect physical displacement of the body or of body pans.
11. What are Johnston‘s organs?
Ans: They are present in the base of the antennae of most insects like mosquitoes. Long setae vibrate when certain frequencies of sound strike them. It vibrates the antennae of these insects. Vibrating setae move the antenna in its socket. It stimulates the sensory cells.
12. What are Tympanal (tympanic) organs?
Ans: Tympanal organs are present in the legs of crickets and in the abdomen of grasshoppers and sonic moths and in the thorax of other insects. Tympana organs consist of a thin and cuticular membrane. It covers a large air sac. The air sac acts as a resonating chamber.
13. What are ommatidia?
Ans: Compound eyes consist of an up to 28.000 receptors. These receptors are called ommatidia. The ommatidia are fused into a multifaceted eye.
14. Name the parts of ommatidia.
Ans: Lens. Crystalline cone, Retinula cells and Pigment cells
15. What are Retinula cells of ommatidium?
Ans: These are special cells of the ommatidium. Retinula has a special light-collecting area, called the rhabdom. The rhabdom converts light energy into nerve impulses.
16. What are Malpighian tubules?
Ans: Malpighian tubules and the rectum are primary excretory structures in the insects. Malpighian tubules end blindly in the haemocoel. They open in to the gut at the junction of the mid gut and the hindgut.
17. Name the endocrine glands of the insects.
Ans: corpora allata and prothoracic glands
18. Name the hormones involved in the synthesis of ecdysone.
Ans: Ecdysiotropin Thoracotropic hormone, ecdysone
19. Name the hormones involved in the moulting of insects.
Ans: These are two hormones: Ecdysone and Juvenile hormones
20. What are pheromones?
Ans: The chemicals released by an animal that change the behavior or physiology of another member of the same specks is called pheromones.
21. Name different types of pheromones.
Ans: Sex pheromones, Caste-regulating pheromones, Aggregation pheromone, Alarm pheromones and Tr ailing pheromones.
22. What is the function of Caste-regulating pheromones?
Ans: They are used by social insects to control the development of individuals in a colony. Example: The female bee feed the larva with royal jelly. The amount of royal jelly determines whether the larva will become a worker or a queen.
23. What is the function of Trailing pheromone?
Ans: It is released by foraging insects. These pheromones help other members of the colony to identify the location and quantity of food. Example: Ants often mows on a pheromone path to and from a food source.
24. What is indirect fertilization?
Ans: A few insects, including silverfish and springtails have indirect fertilization. The male deposits a spermatophore. The female picks up later.
25. What are sperm receptacles in insects?
Ans: The male usually transfer sperm into sperm receptacle of female. Sperm receptacle is an out pocket of the female reproductive tract.
26. What is meant by larva instar?
Ans: Some insects are produced in immature stages called larval instars.
25. What is Ametabolous metamorphosis?
Ans: In this case. primary differences between adults and larvae are body size and sexual maturity. Both adults and larvae are wingless. The number of molts in the ametabolous development of a species varies.
26. What is Paurometabolous metamorphosis?
Ans: In this case, larvae undergo number of molts between egg and adult stages. The number of molts is species-specific. The immature larva gradually changes into the adult form.
27. What is nymph?
Ans: Immature larva is called nymphs.
28. What is holomatbous metamorphosis?
Ans: Their immature is different from the adult in body form. It has different behaviorband habitat. Therefore, the immatures are called larvae.
29. What is emergence or eclosion?
Ans: The adult open the cocoon with its mandibles and come out. This final process is called emergence or eclosion.
30. What is a caste?
Ans: Each kind of individual in an insect colony is called a caste.
31. Name different castes present in a colony of social insect.
Ans; Queens. Workers. Kings or drones and Soldiers.
32. What are drones?
Ans: Drones develop from unfertilized eggs. They do not work. They are fed by the workers. They leave the hive and mate with queen.
33. Why does the evolution of social insects take place?
Ans: Many individuals leave no offsprings in the evolution of social behavior. Thus these individuals sacrifice for the survival of the colony. This behaviour has puzzled evolutionists for many years. They explain it with the concepts of kin selection and altruism.
34. Name some diseases transmitted by insects.
Ans: Insect transmits diseases like malaria, yellow fever, bubonic plague encephalitis and typhus.