name the components of cockroach mouth parts??
Answers
Answer:
The mouthparts of the cockroach include labrum, mandibles, maxillae and labium.
Labrum or the upper lip is a broad and roughly rectangular shaped structure. It hangs from the front edge of the head on the lower side. Hypo pharynx is a tongue like structure in the floor of the mouth.
Mandibles are a pair of hard, strong, large, dark colored structures found one on either side with jagged inner edges. They move in horizontal motion and crush the food present in-between them.
Maxillae are a pair of structures which lie outside and behind the mandibles. Each consists of three parts known as protopodite, exopodite and endopodite.
Labium is said to be formed by the fusion of the second pair of maxillae. It forms the broad median lower lip and has a pair of 3-segmented labial palps on either side which is sensory in nature.
Explanation:
MOUTHPARTS OF COCKROACH
Mouthparts of insects are modified cephalic appendages. Different insects have adapted themselves to different modes of ingestion of food. The basic structure of mouthparts remains the same. These similar mouthparts are an example of homologous organs. Homometabolous insects have different types of mouthparts in their larvae and adults. Hemimetabolous insects have similar type of mouthparts in their larvae and adults.
The mouthparts of cockroach are biting and chewing type. This biting and chewing type of mouthparts are considered as the most primitive and unspecialized of all the mouthpart types. The other examples include grasshopper, dragonfly and beetle. Also the larvae of mosquito, housefly butterfly and honeybee also have biting and chewing mouthparts.
The mouthparts of cockroach are developed to suit its habit of feeding on solid food and as a result it has well developed mandibles. All the components of the mouthparts are present without any modification. These mouthparts help the cockroach to bite and chew on hard stuffs, consume soft stuffs and also lap upon liquids. The mouthparts also include Labrum, Mandibles, and a pair of first maxillae, labium, and hypopharynx. The following is the structure of each of the mouthpart,
Labrum:
The mouth is covered by labrum. It is also known as upper lip. This labrum is attached to the clypeus. The labrum bears gustatory sensilla on its inner surface. Labrum helps in tasting and also handling the food.
Mandibles:
These are a pair of triangular, hard, unjointed, stout, chitinised structures. The mandibles are located on either side of mouth behind labrum. They are dentate along their inner margins and are masticatory in function. These mandibles are provided with two pairs of muscles namely, adductor and abductor muscles to help the movement of mandibles only in horizontal plane against each other.
First pair of maxillae:
A pair of first maxillae is located behind mandibles on either side of the mouth. The first maxilla has two basal segments called cardo and stipes. Cardo is attached to the head capsule and stipes is attached to the cardo. The stipes has five segmented maxillary palp on its outer side. This palp is situated on a small sclerite called palpifer. Inner to the palp two chitinous lobes namely lacinea and galea are found attached to stipes. Lacinea is pincer like with two terminal denticles whereas galea is the outer soft hood life structure bearing long chitinous bristles. The maxillary palps are used for cleaning the antennae and also the front pair of legs.
Labium:
Labium is formed by the fusion of second pair of maxillae. It is also known as lower lip. The basal segment of labium is called post-mentum. Labium includes two segments namely broad rectangular sub-mentum and a triangular mentum. Also pre-mentum is present in front of the mentum. Pre-mentum is formed by the fusion of two stipes and it bears a small sclerite called palpiger. Each palpiger has a 3-segmented labial palp. At the distal end the pre-mentum bears a pair of paraglossae inner to labial palps. A pair of glossae is present between paraglossae. The paraglossae and glossae together constitute ligula.
Hypopharynx:
It is chitinous, grooved and a rod-like structure found hanging into the preoral cavity. It is also known as ligula or tongue. Hypopharynx divides the proximal part of preoral cavity into a larger anterior cibarium and a posterior salivarium. The salivary duct opens into salivarium at the base of the hypopharynx.