Ebooks

Welcome to the fascinating world of entomology – the study of insects. Insects are among the most diverse and abundant organisms on Earth, playing crucial roles in ecosystems, agriculture, and human health. This practical manual has been crafted to serve as your guide into the fundamentals of entomology, providing a hands-on approach to understanding the morphology, behavior, and classification of these remarkable creatures. Entomology is a multidisciplinary science that encompasses aspects of biology, ecology, physiology, and taxonomy. The “Practical Manual on Fundamentals of Entomology” is designed to cater to the needs of students, researchers, and enthusiasts who seek a comprehensive and practical resource to explore the world of insects. Whether you are a beginner or someone with a background in the biological sciences, this manual aims to enhance your understanding and appreciation of the intricate lives of insects.

Insect collection is a source of recreation for many people and maybe a hobby for those who are interested in studying insects. Methods of collection and preservation of insects are the pre-requisite to studying the insects and their various internal and external organs. After collection, it becomes imperative to keep and preserve the insect specimens intact and safe for a longer time to further study the characters or to develop the insect collection museum. Let‘s have a look and do the different types methods of collection, and devices used for the collection and preservation of insects including immature stages in this practical session. Collection  The purposes of insect collection are: To know the occurrence of a particular insect in a particular locality. Taxonomic study of insects. Identification of insects. To study the bionomics and rearing of insects for various entomological experiments. To develop the insect repository etc.

The grasshoppers are widely distributed throughout the country and may be seen in abundance during monsoon season. For the generalized morphological description, this insect has been considered as the most suitable representative of class insects because its structural details are not much variable. Apart from this, being larger, it can be studied easily. The generalized insect body is divided into 3 distinct body regions: a head, a thorax and an abdomen. Grouping of body segments into distinct regions is known as Tagmosis and the body regions are called Tagmata. The Head

The collected insect samples can be inspected in the laboratory after detaching the antenna and putting them under the microscope. They can also be studied through the permanent slides of different types of antennae with the help of microscope. Antennae are mobile sensory segmented appendages of the head. They articulate with head in front or between the eyes and arise from antennal socket. The size and shape of antennae varies in different insects. They are used for sensory perception which includes motion and orientation, odor, sound, humidity, and a variety of chemical cues. The Sensilla on the antenna acts as tactile, olfaction, carbon dioxide, temperature, wind, humidity, and sound receptors. Structure of Antenna: Antennae consist of three parts

Mouthparts of insects vary among insects of different groups depending upon their feeding habits. They are mainly of two types viz., Mandibulate (feeding mainly on solid food) and haustellate (feeding mainly on liquid food). Insect mouthparts have become modified in various groups to perform the ingestion of different types of food and by different methods. Indeed the modifications in the mouthparts to ingest almost all kinds of the food material, are one of the factors for the success of the group. 1. Biting and chewing type: e.g. Cockroach & grasshopper.

The typical thoracic leg consists of six parts, basal coxa that articulates with the thorax in the pleural region, small trochanter, femur, tibia, segmented tarsus, and pre-tarsus. The coxa is often divided into two parts, the posterior and the anterior (usually the larger part) being called the meron. The trochanter articulates with the coxa but usually forms an immovable attachment with the femur. The femur and tibia are typically the longest leg segments. The tarsus, which is derived from a single segment, - is usually subdivided into individual tarsomeres. The pretarsus may consist of a single claw, but it is usually composed of a pair of moveable claws and one or more pads or bristles. Legs are usually looked upon as the principal organs of terrestrial locomotion.

The complete system of veins of a wing is termed venation or neuration. Generally in all the insects, there is some similarity in wing venation and therefore, it is presumed that all types of wing venation have developed from the common base or the same ancestor. Using an extensive study of wing venation in different groups of insects, Comstock and Needham constructed a hypothetical type of wing venation from which all other types have presumably been derived. According to them the primitive wing venation has developed from two tracheae which are situated on the anterior and the posterior basal margins of wings and their branches are spread all over the wing.

Metamorphosis and immature stages The change in growth and development (form) of an insect during its life cycle from birth to maturity is called metamorphosis. There are four basic types of metamorphosis in insects. Ametabola: (No metamorphosis) e.g. Silver fish. These insects have only 3 stages in their life cycle namely egg, young ones and adults. It is most primitive type metamorphosis. The hatching insects resemble the adult in all respects except for the size and called as juveniles. Moulting continues throughout the life. Hemi-metabola: (Incomplete metamorphosis) e.g. Dragonfly, damselfly and may fly. These insects also have 3 stages in their life namely egg, young ones and adults. The young ones are aquatic and are called naiads. They are different from adults in habits and habitat. They breathe by means of tracheal gills. In dragonfly naiad, the lower lip (labium) is called mask which is hinged and provided with hooks for capturing prey. After final moult, the insects have fully developed wings suited for aerial life

The best learning situation requires one specimen and set of tools per two students for studies. Students working in pairs have ample opportunity to fully participate in the dissection and to carefully examine the specimen. They are also able to share and discuss their observations during and after the dissection. Requirements: Dissecting pan with wax pad, dissecting pins, forceps, hand lenses and scissors Procedure Place the specimen in the dissecting pan ventral side up. Use scissors to cut through the exoskeleton‘s ventral side from the head to the posterior end of the abdomen.

Requirements: Dissecting pan with wax pad, dissecting pins, forceps, hand lenses and scissors Procedure Place the specimen in the dissecting pan ventral side up. Use scissors to cut through the exoskeleton‘s ventral side from the head to the posterior end of the abdomen. Pull the cut sides apart and observe the internal organs. Pin the sides of the insect to the dissecting pan. The observation of the reproductive systems of males and females are as follows: Female reproductive system The main functions of the female reproductive system are egg production and storage of male spermatozoa until the eggs are ready to be fertilized. The basic components of the female system are paired ovaries, which empty their mature oocytes (eggs) via the calyces (Calyx) into the lateral oviduct which unite to form the common (median) oviduct.

Requirements: Agriculturally important insects of each order  Orthoptera  Examples: Grasshopper, cricket, etc. Metamorphosis: Paurometabolous Mouthparts: Chewing  Significance: Variable or Pest  Characteristics  •            They are medium to large-sized insects.  •            Antenna is filiform.  •            Mouthparts are mandibulate.  •            Prothorax is large. The pronotum is curved, ventrally covering the pleural region. •             Hindlegs are saltatorial  •            Forewings are leathery, thickened and known as tegmina.  •            They are capable of bending without breaking.  •            Hindwings are membranous with large anal area.  •            They are folded by longitudinal pleats between veins and kept beneath the tegmina.  

Requirements: Insecticides of different types Insecticide chemicals in their “raw” or unformulated state are not usually suitable for pest control. These concentrated chemicals and active ingredients may not mix well with water, may be chemically unstable, and may be difficult to handle and transport. For these reasons, manufacturers add inert substances, such as clays and solvents, to improve application effectiveness, safety, handling, and storage. Inert ingredients do not possess Insecticidal activity and are added to serve as a carrier for the active ingredient. Manufacturers will list the percentage of inert ingredients in the formulation or designate them as “other ingredients” on their labels.

Sprayers Sprayer is a machine used to apply liquid chemicals on plants to control pest and diseases. It can also be used to apply herbicides to control weeds and to spray micro nutrients to enhance plant growth. The main functions of a sprayer are •             Breaking the chemical solution in to fine droplets of effective size.  •            Distributing the droplets uniformly over the plants.  •            Applying the chemicals with sufficient pressure for positive reaching the plants  •            Regulating the amount of liquid applied on plants to avoid excessive application.

Requirements: Clipboard, Pencils, Hand lens, Pocket knife, insect catching nets, attractants, spread sheet Collection bags and vials, Camera etc. Sampling techniques are used to draw valid inferences about the population parameters using the sample statistics Components of an insect sampling program  Knowledge of pest and beneficial insects Identification  Life cycle and biology Injury caused Sample: Sample is a subgroup of the population. It is defined as a collection of individual observations from the population about which inferences are to be made, and is obtained by a specific method.

A  Aspirator - 2, 9, 11  Arthropods – 13, 15  Abdomen- 13, 14, 29, 42, 45, 47, 53, 55, 56,58, 59, 61, 64, 66, 68, 69, 70,  Antennae- 5, 13, 15, 40, 41,43, 57, 63, 67,69,  Ambulatorial- 25  Amplexiform-36. Ametabola- 37, Apodous- 38, 40, 67, 68, 70. Acephalous- 41, 67, 70  Acrididae- 52 Anisoptera- 55, 56  Aphids- 3, 6, 62, 63, 68, 70