Pesticide Definitions PDF

Introduction Arleen Upod-Dela Cruz, MSc Assistant Professor I  Definition of terms Acaricide-Material toxic to mites (Acarina). Activator-Chemical added to a pesticide to increase its toxicity. Active ingredient (a.i.) -Toxic component of a formulated pestici...

Introduction Arleen Upod-Dela Cruz, MSc Assistant Professor I  Definition of terms Acaricide-Material toxic to mites (Acarina). Activator-Chemical added to a pesticide to increase its toxicity. Active ingredient (a.i.) -Toxic component of a formulated pesticide. Adherence- The ability of a material to stick to a particular surface. Adhesive (= Sticker) - Material added to increase pesticide retention; different commercial preparations of methyl cellulose are available for this purpose.  Definition of terms Adjuvant- A spray additive to improve either physical or chemical properties (see also Supplement, Sticker, Adhesive, Spreader, Wetter and Emulsifier). Antibiosis -The resistance of a plant to insect attack by having, for example, a thick cuticle, hairy leaves, toxic sap, etc. Anti-feedant- A chemical possessing the property of inhibiting the feeding of certain insect pests. Asymptote - The point in the growth of a population at which numerical stability is reached. Bait - Foodstuff used for attracting pests; usually mixed with a poison to form a poison bait.  Definition of terms Band application - Treatment of a band of soil in row-crops, usually covering plant rows, with either sprays or granules. Biocide - A general poison or toxicant. Browsing - The eating of foliage of bushes and trees Carrier- Material serving as diluent and vehicle for the active ingredients; usually in dusts. Chemosterilant - Chemical used to render an insect sterile without killing it.  Definition of terms Coarctate pupa - A pupa enclosed inside a hardened shell formed by the previous larval skin. Cocoon - A silken case inside which a pupa is formed. Compatibility - The ability to mix different pesticides without physical or chemical interactions which would lead to reduction in biological efficiency or increase in phyto-toxicity. Concentrated solution (c.s.) - Commercial pesticide preparation before dilution for use.  Definition of terms Concentrate spraying - Direct application of the pesticide concentrates without dilution. Concentration - Proportion of active ingredient in a pesticide preparation, before or after dilution. Contact poison - Material killing pests by contact action, presumably by absorption through the cuticle. Control (noun) - Untreated subjects used for comparison with those given a particular crop protection treatment.  Definition of terms Control (verb) - To reduce damage or pest density to a level below the economic threshold. Legislative: the use of legislation to control the importation and to prevent any spread of a pest within a country. Physical: the use of mechanical (hand picking, etc.) and physical methods (heat, cold, radiation, etc.) of controlling pests. Cultural: regular farm operations designed to destroy pests. Chemical: the use of chemical pesticides as smokes, gas, dusts, and sprays to poison pests. Biological: the use of natural predators, parasites and disease organisms to reduce pest populations. Integrated: the very carefully reasoned use of several different methods of pest control in conjunction with each other to control pests with a minimum disturbance to the natural situation.  Definition of terms Cover- Proportion of the surface area of the target plant on which the pesticide has been deposited. Defoliant - Spray which induces premature leaf-fall. Desiccant- Chemical which kills vegetation by inducing excessive water loss. Diluent - Component of spray or dust that reduces the concentration of the active ingredient, and may aid in mechanical application but does not directly affect toxicity.  Definition of terms Disinfect - To free from infection by destruction of the pest or pathogen established in or on plants or plant parts. Dispersal - Movement of individuals out of a population (emigration) or into a population (immigration). Diurnal - Active during the daytime. Dormant - Alive but not growing; buds with an unbroken cover of scales; quiescent; inactive; a resting stage.  Definition of terms Dose; dosage - Quantity of pesticide applied per individual, or per unit area, or per unit volume, or per unit weight. Drift - Spray or dust carried by natural air currents beyond the target area. Ecdysis - The molting (shedding of the skin) of larval arthropods from one stage of development to another – the final molt leading to the formation of the puparium or chrysalis.  Definition of terms Ecesis (= Oikesis) - The establishment of an organism in a new habitat; accidental dispersal and establishment in a new area. Economic damage - The injury done to a crop which will justify the cost of artifical control measures. Economic-injury level - The lowest population density that will cause economic damage. Economic pest - A pest causing a crop loss of about 5–10%, according to definition.  Definition of terms Economic threshold - The pest population level at which control measures should be started to prevent the pest population from reaching the economic injury level. Efficiency of a pest control measure - The more or less fixed reduction of a pest population regardless of the number of pests involved. Effectiveness of a pest control measure - This is shown by the number of pests remaining after control treatment.  Definition of terms Emulsifiable concentrate (e.c.) - Liquid formulation that when added to water will spontaneously disperse as fine droplets to form an emulsion (= Miscible oil). Emulsifier - Spray additive which permits formation of a stable suspension of oil droplets in aqueous solution, or of aqueous solution in oil. Emulsion - A stable dispersion of oil droplets in aqueous solution, or vice cersa. Entomophagous - An animal (or plant) which feeds upon insects.  Definition of terms Fecundity - Capacity to produce offspring (reproduce); power of a species to multiply rapidly. Formulation - Statement of nature and amount of all constituents of a pesticide concentrate. - Method of preparation of a pesticide concentrate. Fossorial legs - Modified for digging; in the habit of digging or burrowing.  Definition of terms Frass - Wood fragments made by a wood-boring insect, usually mixed with the feces. Fumigant - Pesticide exhibiting toxicity in the vapour phase. Furrow application - Placement of pesticides with seed in the furrow at the time of sowing. Generation - The period from any given stage in the life cycle (usually adult) to the same stage in the offspring.  Definition of terms Grub (White) - A scarabaeiform larva; thick-bodied, with a well-developed head and thoracic legs, without abdominal prolegs, usually sluggish in behaviour; general term for larvae of Coleoptera. Hemimetabolous - Insects having a simple metamorphosis, like that in the Orthoptera, Heteroptera, and Homoptera. Herbivorous - Feeding on plants (phytophagous). Holometabolous - Insects having a complete metamorphosis, as in the Diptera, Hymenoptera, Coleoptera, Lepidoptera.  Definition of terms Host - The organism in or on which a parasite lives; and the plant on which an insect feeds. Hypermetamorphosis - A type of complete metamorphosis in which the different larval instars represent two or more different types of larvae. Imago - The adult, or reproductive stage of an insect. Inert - A material having no biological action. Infect - To enter and establish a pathogenic relationship with a plant (host); to enter and persist in a carrier.  Definition of terms Infest - To occupy and cause injury to either a plant, soil or stored products. Insecticide - A toxin effective against insects. Instar - The form of an insect between successive molts; the first instar being the stage between hatching and the first molt. Larva - The immature stages of an insect, between the egg and pupa having a complete metamorphosis Larvicide - Toxicant (poison) effective against insect larvae. Life table - The separation of a pest population into its different age components (e.g. eggs, larvae, pupae, adults).  Definition of terms Miticide - Preferably called Acaricide. Molluscicide - Toxicant effective against slugs and snails. Monophagous - An insect restricted to a single host plant species. Mortality - Population decrease factor; death rate. Natality - Population ‘increase’ factor; birth rate. Nematicide - Toxicant effective against nematodes (= eelworms). Nocturnal - Active at night. Definition of terms Nymph - The immature stage of an insect that does not have a distinct pupal stage; also the immature stages of Acarina that have eight legs  Definition of terms Oligophagous (= Stenophagous) - An animal feeding upon only a few, closely related, host plants; or it may be an animal parasite. Ovicide - Toxicant effective against insect or mite eggs. Oviparous - Reproduction by laying eggs. Definition of terms Parasite - An organism living in intimate association with a living organism (plant or animal) from which it derives material essential for its existence while conferring no benefit in return.  Parasitoid - An organism alternately parasitic and free-living; most parasitic Hymenoptera and Diptera fall into this category as usually only the larvae are parasitic.  Parthenogenesis- Reproduction without fertilization; usually through eggs but sometimes through viviparity.  Definition of terms Persistence - The term applied to chemicals that remain active for a long period of time after application. Pest - An animal or plant causing damage to man’s crops, animals or possessions. Pest density - The population level at which a pest species causes economic damage. Pest management - The careful manipulation of a pest situation, after extensive consideration of all aspects of the life system as well as ecological and economic factors.  Definition of terms Pest spectrum - The complete range of pests attacking a particular crop. Pesticide - A chemical which by virtue of its toxicity (poisonous properties) is used to kill pest organisms. A term of wide application which includes all the more specific applications – insecticide, acaricide, bactericide, fungicide, herbicide, molluscicide, nematicide, rodenticide, etc. Pheromone (= Ectohormone).- A substance secreted by an insect to the exterior causing a specific reaction in the receiving insects. Phytophagous - Herbivorous; plant eating.  Definition of terms Phytosanitation - Measures requiring the removal or destruction of infected or infested plant material likely to form a source of reinfection or reinfestation. (See Crop Hygiene.) Poison bait - An attractant foodstuff for insects, molluscs, or rodents, mixed with an appropriate toxicant. Polyphagous - An animal feeding upon a range of hosts. Pre-access interval - The interval of time between the last application of pesticide to an area and safe access to the area for domestic livestock, and man.  Definition of terms Pre-harvest interval - The interval of time between the last application of pesticide and the safe harvesting of edible crops for immediate consumption. Proprietory name - Distinguishing name given by the manufacturer to a particular formulated product. Protective clothing - Clothing to protect the spray operator from the toxic effects of crop protection chemicals. This may include rubber gloves, boots, apron, respirator, face mask, etc. Pupa - The stage between larva and adult in insects with complete metamorphosis; a non-feeding and usually inactive stage.  Definition of terms Quarantine - All operations associated with the prevention of importation of unwanted organisms into a territory, or their exportation from it. Repellant - A chemical which has the property of inducing avoidance by a particular pest. Residue - Amount of pesticide remaining in or on plant tissues (or in soil) after a given time, especially at harvest time. Resistance - The natural or induced capacity to avoid or repel attack by pests (or parasites). Also the ability to withstand the toxic effects of a pesticide or a group of pesticides, often by metabolic detoxification.  Definition of terms Rodenticide - A toxicant effective against rodents. Roguing - The removal of unhealthy or unwanted plants from a crop. Run-off - The process of spray shedding from a plant surface during and immediately after application, when droplets coalesce to form a continuous film and surplus liquid drops from the surface. Seed dressing - A coating (either dry or wet) of protectant pesticide applied to seeds before planting. Semiochemicals - Chemicals produced by one organism that incite a response in another organism.  Definition of terms Spray - Air-carried: spray propelled to target in a stream of air. o Coarse: dispersion of droplets of mass median diameter over 200 µm. o Concentrate: undiluted commercial pesticide preparation. o Fine: dispersion of droplets of mass median diameter from 50–150 µm. o Floor: spray applied to the litter on the ground surface. o High-volume: over 1200 1/ha on bushes and trees; over 700 1/ha on ground crops (or over 400 1/ha according to definition). o Low-volume: spray of 250–600 1/ha on bushes and trees; 50– 250 1/ha on ground crops (or 5–400 1/ha). o Median-volume: 600–1200 1/ha on bushes and trees; 250–700 1/ha on ground crops. o Mist: dispersion of droplets of 50–100 µm in diameter. o Ultra-low-volume: less than 50 1/ha on ground crops; less than 250 1/ha on trees and bushes (or less than 51 1/ha according to definition).  Definition of terms Spread - Uniformity and completeness with which a spray deposit covers a continuous surface, such as a leaf or a seed. Stability - The ability of a pesticide formulation to resist chemical degradation over a period of time. Sticker - A material of high viscosity used to stick powdered seed dressings on to seeds; two commonly used stickers are paraffin and methyl cellulose. A solution of methyl cellulose can be added to a spray to increase retention on plant foliage.  Definition of terms Stomach poison - A toxicant (poison) which operates by absorption through the intestine after having been injested by the insect, usually on plant material. Susceptible - Capable of being easily infested or infected; not resistant. Systemic - A pesticide absorbed through the plant surfaces (usually roots) and translocated through the plant vascular system. Taxonomy - The laws of classification as applied to natural history; identification of plant and animal species. Tolerance - Ability to endure infestation (or infection) by a particular pest (or pathogen) without showing severe symptoms of distress.  Definition of terms Toxicity - Ability to poison, or to interfere adversely with vital processes of the organism by physico-chemical means. Tracer - Additive to facilitate location of a deposit, by radioactive or fluorescent means. Translocation - The uptake of a pesticide into part of a plant body and its subsequent dispersal to other parts of the plant body. Trap crop - Crop of plants (sometimes wild plants) grown especially to attract insect pests, and when infested either sprayed or collected and destroyed. Trap plants usually grown between the rows of the crop plants or else peripherally.  Definition of terms Vector - Organisms able to transmit viruses or other pathogens either directly or indirectly. Direct virus vectors include insects, mites and nematodes. Viviparous - Giving birth to living young (Aphidoidea). THANK YOU  Concept of Insect Physiology and Toxicology It is desirable to study insect physiology to identify and understand systems that are unique to insects and not found in mammals, birds, reptiles or fish. If insecticides are developed that target those systems, and only those systems, there is a good chance that the insecticides will be non-toxic to other species and therefore safe to handle and safe for the environment in which they are used. For example there are some insecticides for use against fleas on domestic pets that target the pupal stage of insect development and prevent the fleas from reaching adulthood. These chemicals are of extremely low toxicity to mammals and therefore safe for the pets and their owners.  Insects play a vital role in nutrient cycling, the process by which nutrients are transferred from living organisms to the environment and then back to living organisms. They do this by consuming plants and a nimals and breaking down organic matter. (PDF) The Role of Insects in Nutrient Cycling: Unsung Heroes of Ecosystem Health (researchgate.net)  Insecticide Use Patterns Indiscriminate use of insecticides in controlling insect pests of agricultural crops has been implicated in the development of resistance in disease vectors that breed within farming areas. Since vector control strategies are insecticide based, it is important to study insecticide resistance in farming areas such as irrigation sites where vectors are breeding. The indiscriminate use of insecticides in the area, the residue levels in soil and water samples from breeding grounds  Pesticide residues on food lead to between 4,000 and 20,000 new cases of cancer every year. The contamination results in anywhere from 6 million to 14 million fish deaths and 67 million bird deaths.  Pesticidescan eliminate some animals' essential food sources, causing the animals to relocate, change their diet or starve.  Plant Protection Product is a more specific phrase than pesticide (PPP). Plant protection products are "pesticides" that guard desirable or practical plants or crops.  Types of Pesticides Herbicides Herbicides are pesticides designed for controlling unwanted plants. They are commonly used in the home garden or farm where there is a problem with weeds that compete with desirable crops.  Do herbicides have negative effects on humans or the environment? Yes, herbicides can have negative environmental effects depending on the type of plant they are targeting, how often it is applied, and where it is poured onto.  Herbicides can affect organisms when they are in liquid form by entering their system when they drink water. The liquid herbicide also competes with oxygen for use in photosynthesis with other aquatic lifeforms such as algae.  Insecticides Insecticides are a family of chemicals designed to control insects. Most insecticides work by poisoning the nervous system or interfering with metabolic processes. Insects undergo chemical changes when they eat poison – this is how they die.  Fungicides Fungicides are used to control fungal plant diseases. They can be natural or synthetic compounds, but they all work by disrupting the cell membranes of fungi so that the organism cannot survive.  Rodenticides Rodenticides are toxic substances, often in the form of bait, for use in eradicating rodents. Rodents find these bait and often die from eating them or by pest-control agents laying traps that prevent rats from entering buildings.  Germicides Germicides are a type of chemical used to kill unwelcome organisms such as bacteria, viruses, and fungi. The most common types of germicide agents include chlorine, nitrates, alcohols, and acids  What are the most common types of common household germicides? Germicidal soaps, gels, or cleansers. All these contain chemicals that cause infections to be killed, including antimicrobials like triclosan.  Algicides Algicides are essential to kill the algae that cause all your hard work of cleaning up after the pool. Algae come in two forms – blue-green and thread- like. It’s easy for both types of algae to grow, especially in warm water over 75°F (24°C).  Bactericides A bactericide is a drug that kills bacteria or inhibits their growth, either by stopping plant cell walls from forming or blocking some essential process needed for the cells to reproduce.  Larvicides Larvicides are insecticides that are designed to kill larval mosquito species. Mosquito larvae are the youngest, smallest stages in the development of these insects. They live in still water that cannot be walked through or dipped into, requiring chemical intervention for their extermination.  TOPIC 2 A. Insect Growth, Development, and Reproduction  Molting An insect’s skeleton is on the outside of its body and is called an exoskeleton. It serves as a support for muscles and internal organs as well as a covering. As the insect’s rigid exoskeleton cannot expand much, it must be shed and replaced with a larger one as the insect grows. This process is called molting. The life stage between each molt is called an instar. Molting is governed by hormones. Cuticle secretion and the molt cycle are controlled by ecdysone, a steroid hormone. The hormone is secreted by a gland in the thorax, which is in turn controlled by a hormone from the brain. Whenever the brain receives the appropriate stimulus, the insect will molt. A new cuticle forms under the old one, then the old exoskeleton splits and the insect wriggles its way out. Many insects eat their own discarded skin. The new cuticle is soft at first. The insect may swallow air to expand its own volume and stretch the new exoskeleton before in hardens, usually within about an hour.  Kinds of Insect Growth Molting may occur up to three or four times or, in some insects, fifty times or more during its life. The two kinds of insect growth are directly related to molting patterns. Those that show a determinate pattern of growth have a fixed number of molts, whereas those that have indeterminate growth continue to molt indefinitely Classification of Insects According to Growth  The Stages of Molting 1. Apolysis a. Molting hormones are released into the haemolymph and the old cuticle separates from the underlying epidermal cells. The epidermis increases in size due tomitosis and then the new cuticle is produced. Enzymes secreted by the epidermal cells digest the old endocuticle, not affecting the old sclerotised exocuticle.  2. Ecdysis a. This begins with the splitting of the old cuticle, usually starting in the midline of the thorax’s dorsal side. The rupturing force is mostly from haemolymph pressure that has been forced into thorax by abdominal muscle contractions caused by the insect swallowing air or water. After this the insect wriggles out of the old cuticle.  3. Sclerotisation a. After emergence the new cuticle is soft and this a particularly vulnerable time for the insect as its hard protective coating is missing. After an hour or two the exocuticle hardens and darkens. The wings expand by the force of haemolymph into the wing veins.  Life Cycle An insect’s life-cycle can be divided into three types 1. Ametabolous or No metamorphosis 2.Hemimetabolous or Incomplete metamorphosis 3. Holometabolus or Complete metamorphosis  Ametabolous No metamorphosis These insects are primitively wingless where the only difference between adult and nymph is size. Example: Order: Thysanura (Silverfish).  Hemimetabolous Incomplete metamorphosis The terrestrial young are called nymphs and aquatic young are called naiads. Insect young are usually similar to the adult. Wings appear as buds on the nymphs or early instars. When the last moult is completed the wings expand to the full adult size. Example: Order: Odonata (Dragonflies).  Holometabolus Complete metamorphosis These insects have a different form in their immature and adult stages, have different behaviors and live in different habitats. The immature form is called larvae and remains similar in form but increases in size. They usually have chewing mouthparts even if the adult form mouth parts suck. At the last larval instar phase the insect forms into a pupa, it doesn’t feed and is inactive, and here wing development is initiated, and the adult emerges. Example: Order: Lepidoptera (Butterflies and Moths).  Sexual and Asexual Reproduction Most insects reproduce via sexual reproduction, i.e. the egg is produced by the female, fertilized by the male and oviposited by the female. Eggs are usually deposited in a precise microhabitat on or near the required food. However, some adult females can reproduce without male input. This is known as parthenogenesis and in the most common type of parthenogenesis the offspring are essentially identical to the mother. This is most often seen in aphids and scale insects. B. Metabolic Systems of Insects  Insect External Anatomy The insect is made up of three main body regions (tagmata), the head, thorax and abdomen. The head comprises six fused segments with compound eyes, ocelli, antennae and mouthparts, which differ according to the insect’s particular diet, e.g. grinding, sucking, lapping and chewing. The thorax is made up of three segments: the pro, meso and meta thorax, each supporting a pair of legs which may also differ, depending on function, e.g. jumping, digging, swimming and running. Usually the middle and the last segment of the thorax have paired wings. The abdomen generally comprises eleven segments and contains the digestive and reproductive organs  Ocelli in insects are simple photo-receptors that detect light and movement. They consist of a single lens and several sensory cells. Unlike compound eyes, ocelli do not form a complex image of the environment. Most arthropods possess ocelli  Muscular System Many insects are able to lift twenty times their own body weight and may jump distances that are many times greater than their own length. This is not because they are strong but because they are so small. Muscle power is proportional to its cross-sectional area. Because the mass (the insect's body) that is moved is in proportion to its volume and the fact that they also have a better leverage system than humans do, they can jump remarkable distances.  The muscular system of insects ranges from a few hundred muscles to a few thousand. Unlike vertebrates that have both smooth and striated muscles, insects have only striated muscles. Muscle cells are amassed into muscle fibers and then into the functional unit, the muscle. Muscles are attached to the body wall, with attachment fibers running through the cuticle and to the epicuticle, where they can move different parts of the body including appendages such as wings. The muscle fiber has many cells with aplasma membrane and outer sheath or sarcolemma. The sarcolemma is invaginated and can make contact with the tracheole carrying oxygen to the muscle fiber. Arranged in sheets or cylindrically, contractile myofibrils run the length of the muscle fiber. Myofibrils comprising a fine actin filament enclosed between a thick pair of myosin filaments slide past each other instigated by nerve impulses.  Muscles can be divided into four categories: Visceral These muscles surround the tubes and ducts and produce peristalsis as demonstrated in the digestive system. Segmental Causing telescoping of muscle segments required for molting, increase in body pressure and locomotion in legless larvae.  Muscles can be divided into four categories: Appendicular Originating from either the sternum or the tergum and inserted on the coxae these muscles move appendages as one unit. These are arranged segmentally and usually in antagonistic pairs. Appendage parts of some insects, e.g. the galea and the lacinia of the maxillae, only have flexor muscles. Extension of these structures is by hemolymph pressure and cuticle elasticity.  Muscles can be divided into four categories: Flight Flight muscles are the most specialized category of muscle and are capable of rapid contractions. Nerve impulses are required to initiate muscle contractions and therefore flight. These muscles are also known as neurogenic or synchronous muscles. This is 24 because there is a one to one correspondence between action potentials and muscle contractions. In insects with higher wing stroke frequencies the muscles contract more frequently than at the rate that the nerve impulse reaches them and are known as asynchronous muscles.  Flight has allowed the insect to disperse, escape from enemies, environmental harm, and colonize new habitats. One of the insect’s key adaptations, the mechanics of flight differs from other flying animals because their wings are not modified appendages. Fully developed and functional wings occur only in adult insects. To fly, gravity and drag (air resistance to movement) has to be overcome. Most insects fly by beating their wings and to power their flight they have either direct flight muscles attached to the wings, or an indirect system where there is no muscle to wing connection and instead they are attached to a highly flexible box like thorax  Direct flight muscles generate the upward stroke by the contraction of the muscles attached to the base of the wing inside the pivotal point. Outside the pivotal point the downward stroke is generated through contraction of muscles that extend from the sternum to the wing. Indirect flight muscles are attached to the tergum and sternum. Contraction makes the tergum and base of the wing pull down. In turn this movement lever the outer or main part of the wing in strokes upward. Contraction of the second set of muscles, which run from the back to the front of the thorax, powers the downbeat. This deforms the box and lifts the tergum. Digestive System  An insect uses its digestive system to extract nutrients and other substances from the food it consumes. Most of this food is ingested in the form of macromolecules and other complex substances (such as proteins, polysaccharides, fats, and nucleic acids) which must be broken down by catabolic reactions into smaller molecules (i.e. amino acids, simple sugars, etc.) before being used by cells of the body for energy, growth, or reproduction. This break-down process is known as digestion.  The insect's digestive system is a closed system, with one long enclosed coiled tube called the alimentary canal which runs lengthwise through the body.  Alimentary canal functions The alimentary canal only allows food to enter the mouth, and then gets processed as it travels toward the anus. The insect’s alimentary canal has specific sections for grinding and food storage, enzyme production and nutrient absorption.  Sphincters control the food and fluid movement between three regions. Sphincters The three regions include the foregut (stomatodeum), the midgut (mesenteron), and the hindgut (proctodeum). Salivary glands and salivary reservoirs The salivary glands produce saliva. The salivary ducts lead from the glands to the reservoirs and then forward through the head to an opening called the salivarium behind the hypopharynx; which movements of the mouthparts help mix saliva with food in the buccal cavity. Saliva mixes with food which travels through salivary tubes into the mouth, beginning the process of breaking it down.  Food is moved down the gut by muscular contractions called peristalsis. 1. Stomatodeum (foregut): This region stores, grinds and transports food to the next region. Included in this are the buccal cavity, the pharynx, the oesophagus, the crop (stores food), and proventriculus or gizzard (grinds food).  1. Stomatodeum (foregut): Salivary secretions from the labial glands dilute the ingested food. In mosquitoes (Diptera), which are blood- feeding insects, anticoagulants and blood thinners are also released here.  2. Mesenteron (midgut): Digestive enzymes in this region are produced and secreted into the lumen and here nutrients are absorbed into the insect’s body.  2. Mesenteron (midgut): This membrane prevents food pathogens from contacting the epithelium and attacking the insects’ body. It also acts as a filter allowing small molecules through, but preventing large molecules and particles of food from reaching the midgut cells  3. Proctodeum (hindgut) This is divided into three sections; the anterior is the ileum, the middle portion, the colon, and the wider, posterior section is the rectum.  3. Proctodeum (hindgut) Like other animals, the removal of toxic metabolic waste requires water. However, for very small animals like insects, water conservation is a priority. Because of this, blind-ended ducts called Malpighian tubules come into play.  3. Proctodeum (hindgut) These ducts emerge as evaginations at the anterior end of the hindgut and are the main organs of osmoregulation and excretion. These extract the waste products from the haemolymph, in which all the internal organs are bathed).  Circulatory System The main function of insect blood, hemolymph, is that of transport and it bathes the insect’s body organs. Making up usually less than 25% of an insect’s body weight, it transports hormones, nutrients and wastes and has a role in osmoregulation, temperature control, immunity, storage (water, carbohydrates and fats) and skeletal function. It also plays an essential part in the molting process. An additional role of the hemolymph in some orders, can be that of predatory defense. It can contain unpalatable and malodourous chemicals that will act as a deterrent to predators.  Respiratory System Insect respiration is accomplished without lungs using a system of internal tubes and sacs through which gases either diffuse or are actively pumped, delivering oxygen directly to tissues that need oxygen and eliminate carbon dioxide via their cells. Since oxygen is delivered directly, the circulatory system is not used to carry oxygen, and is therefore greatly reduced; it has no closed vessels (i.e., no veins or arteries), consisting of little more than a single, perforated dorsal tube which pulses peristaltically, and in doing so helps circulate the hemolymph inside the body cavity.  Respiratory System Air is taken in through spiracles, openings which are positioned laterally in the pleural wall, usually a pair on the anterior margin of the meso and meta thorax, and pairs on each of the eight or less abdominal segments, Numbers of spiracles vary from 1 to 10 pairs. The oxygen passes through the tracheae to the tracheoles, and enters the body by the process of diffusion. Carbon dioxide leaves the body by the same process.  Reproductive System Most insects have a high reproductive rate. With a short generation time, they evolve faster and can adjust to environmental changes more rapidly than other slower breeding animals. Although there are many forms of reproductive organs in insects, there remains a basic design and function for each reproductive part. These individual parts may vary in shape (gonads), position (accessory gland attachment), and number (testicular and ovarian glands), with different insect groups.  Female The female insect’s main reproductive function is to produce eggs, including the egg’s protective coating, and to store the male spermatozoa until egg fertilisation is ready. The female reproductive organs include, paired ovaries which empty their eggs (oocytes) via the calyces into lateral oviducts, joining to form the common oviduct.  Female Egg development is mostly completed by the insect’s adult stage and is controlled by hormones that control the initial stages of oogenesis and yolk deposition. Most insects are oviparous, where the young hatch after the eggs have been laid.  Female Insect sexual reproduction starts with sperm entry that stimulates oogenesis, meiosis occurs and the egg moves down the genital tract. Accessory glands of the female secrete an adhesive substance to attach eggs to an object and they also supply material that provides the eggs with a protective coating. Oviposition takes place via the female ovipositor.  Male The male’s main reproductive function is to produce and store spermatozoa and provide transport to the reproductive tract of the female. Sperm development is usually completed by the time the insect reaches adulthood. The male has two testes, which contain follicles in which the spermatozoa are produced. These open separately into the sperm duct or vas deferens and store the sperm. The vas deferentia then unite posteriorally to form a central ejaculatory duct this opens to the outside on an aedeagusor a penis. Accessory glands secrete fluids that comprise the spermatophore. This becomes a package that surrounds and carries the spermatozoa, forming a sperm-containing capsule.  C. Insect Coordination and Integration Insect Flight Insect flight is the most energy-demanding activity of animals. It requires the coordination and cooperation of many tissues, with the nervous system and neurohormones controlling the performance and energy metabolism of muscles, and of the fat body, ensuring that the muscles and nerves are supplied with essential fuels throughout flight.  Insect Flight Octopamine, which acts as neurotransmitter, neuromodulator or neurohormone in insects, has a central role in flight. It is present in brain, ventral ganglia and nerves, supplying peripheral tissues such as the flight muscles, and its concentration in hemolymph increases during flight.  Insect Path Integration Well before the advent of GPS, humans have had a need to revisit specific sites, for instance, the home cave or a specific tree that is abundant in fruit. While a map would be useful in these instances to avoid getting lost, creating a map requires information of where one is relative to the goal or the starting point of a trip. This is particularly difficult if there are no conspicuous features in the environment, for example in the desert or at sea.  Insect Path Integration Many arthropods, including a wide variety of insects — for example, shield bugs, field crickets, cockroaches, flies, honeybees and ants — are known to use this strategy to return to their nest, hive or burrow by the shortest possible route after convoluted foraging trips. This is critical for survival since it reduces predatory pressure and allows the animal to minimize exposure to hostile weather conditions. In principle, during path integration animals continuously keep track of the distance and the directions traveled and then integrate this information to produce a single ‘home’ vector that takes them directly back to the point of origin. THANK YOU