Agri Quiz: Entomology: Insect Morphology MCQ

Correct Answer: Greek
Entomology is derived from the Greek words 'Entomon' meaning insect and 'Logus' meaning study. It's a branch of zoology focusing on insects.

Correct Answer: Arthropoda
Insects belong to the Phylum Arthropoda, derived from the Greek words 'Athro' (segmented) and 'Poda' (legs). Arthropoda is the largest phylum in the animal kingdom.

Correct Answer: Carboniferous
While insects originated in the Devonian period, the first insects with wings and those feeding on plants (phytophagous) appeared during the Carboniferous period.

Correct Answer: Bilateral Symmetry
Insects exhibit bilateral symmetry, meaning their body can be divided into two equal halves along a central axis. This is a common feature among many mobile animals.

Correct Answer: Three (Head Thorax Abdomen)
An insect's body is characteristically divided into three main segments: the Head, Thorax, and Abdomen. This tripartite division is a key feature of the class Insecta.

Correct Answer: Open Type
Insects possess an open circulatory system where the blood, called haemolymph, flows freely within the body cavity (haemocoel) bathing the organs directly.

Correct Answer: Chitin-protein complex
All insects have an exoskeleton made of cuticle, which is primarily a composite material consisting of chitin (a polysaccharide) and proteins. This provides support and protection.

Correct Answer: Malpighian Tubules
Excretion in insects is mainly carried out by Malpighian tubules, which absorb waste products from the haemolymph and pass them into the hindgut. Green glands are typical of Crustacea.

Correct Answer: Crustacea
Crustaceans, like crabs and prawns, are distinguished by having two pairs of antennae, gills for respiration, and green glands for excretion. Insects typically have one pair of antennae and respire via tracheae.

Correct Answer: Arachnida
The class Arachnida, which includes spiders, scorpions, mites, and ticks, is characterized by the complete absence of antennae. They typically possess four pairs of legs.

Correct Answer: Cervix
The flexible, neck-like membranous region connecting the head capsule to the thorax is called the cervix. It allows for head movement.

Correct Answer: Notum/Tergum
The dorsal (upper) surface plates of each thoracic segment are referred to as the Notum or Tergum. The ventral surface is the Sternum, and the lateral surfaces are the Pleura.

Correct Answer: Meso- and Metathorax
In winged insects, the wings are primarily attached to the second (Mesothorax) and third (Metathorax) thoracic segments. These two segments together are often called the Pterothorax.

Correct Answer: Uromeres
The segments that make up the insect abdomen are specifically called uromeres. The abdomen typically consists of up to 11 segments.

Correct Answer: Segment 9
The external reproductive structures of male insects are typically found associated with the 9th abdominal segment. Female genitalia are often on segments 8 and 9.

Correct Answer: Thorax and Abdomen
Spiracles are usually located laterally on the thoracic segments (meso- and metathorax) and the anterior abdominal segments. Typically, there's one pair per segment, up to the 8th abdominal segment.

Correct Answer: Hypognathous
Hypognathous refers to a head orientation where the mouthparts are positioned ventrally, pointing downwards, perpendicular to the body axis. This is common in grasshoppers (Orthopteroid).

Correct Answer: Forwards
In the prognathous condition, the head is oriented horizontally, and the mouthparts project directly forward, parallel to the body axis. This type is also known as Coleopteroid.

Correct Answer: Opisthognathous
Opisthognathous describes a head type where the mouthparts are directed backward and held ventrally, often between the front legs. This is characteristic of Hemiptera and also called Hemipteroid.

Correct Answer: Biting and Chewing
The biting and chewing type (Mandibulate) mouthparts are regarded as the most basic or primitive type, from which other forms have evolved. Examples include grasshoppers and beetles.

Correct Answer: Hymenoptera
Chewing and lapping mouthparts are found in insects like honeybees and wasps (Order Hymenoptera). They are used for lapping up liquids like nectar and manipulating solids like wax.

Correct Answer: Four
The 'Bug Type' piercing-sucking mouthparts, found in Hemiptera (bugs, aphids, leafhoppers), typically consist of four stylets (modified mandibles and maxillae) used to penetrate plant tissues.

Correct Answer: Six
Mosquitoes (Order Diptera) possess piercing-sucking mouthparts adapted for feeding on blood or nectar, typically utilizing six stylets to penetrate the host's skin.

Correct Answer: Thysanoptera
Rasping and sucking mouthparts are characteristic of the order Thysanoptera (thrips). These mouthparts are asymmetrical, often lacking the right mandible, and possess three stylets.

Correct Answer: Housefly
Sponging mouthparts are found in insects like the housefly (Order Diptera). They are adapted for soaking up liquid or liquefied food through sponge-like lobes (labella).

Correct Answer: Siphoning
Lepidopterans (butterflies and moths) have siphoning mouthparts, where the galeae of the maxillae are modified into a long, coiled proboscis for sucking nectar from flowers.

Correct Answer: Labrum
The Labrum is a flap-like structure located at the front of the mouth cavity, functioning as the upper lip. The Labium forms the lower lip.

Correct Answer: One pair
Centipedes (Class Chilopoda) are characterized by having one pair of legs per body segment, except for the first and last few segments. Their front legs are often modified into poison claws.

Correct Answer: Physogastry
The condition where the abdomen of a queen insect, particularly in termites and ants, becomes massively enlarged due to hypertrophied ovaries is called physogastry. The enlarged abdomen itself is referred to as physogastric.