INSECTS
THE INSECT BODY
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| Internet picture |
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| Picture by: Daine Casallas |
METAMORPHOSIS AND GROWTH
Depending on the species, insects develop into an adult through one of two processes, these are complete metamorphosis and gradual metamorphosis.
COMPLETE METAMORPHOSIS
It has four dramatically different stages. In this process the larva is an immature form of an animal that looks very different from the adult.
GRADUAL METAMORPHOSIS
This type of metamorphosis hasn´t got distinctly different larval stage- an egg hatches. The medium stage is called nymph, which often resembles the adult insect.
INTERNAL STRUCTURE
- Nervous system: Some insects have a gigant fiber system. The central nervous system consist of a pair of longitudinal nerve chords that lie along the ventral surface of the abdomen and thorax, a brain or a ganglion.
- Digestive system: Consists of a foregut (esophagus, crop and gizzard), midgut (stomach and gastric ceca) and hindgut (intestine, rectum and anus). The majority of insects feed on plant juices and plant tissues. Others as ants and termites cultivate fungus gardens as a source of food.
- The feeding habits of insects are determined to some extent by their mouthparts, which are specialized for each type of feeding.
- Excretory system: Malpighian tubules are very efficient, both as excretory organs and as a mean of conserving body fluids. Many insects can reasorb nearly all water from the rectum to mantain balancing between water and salt.
- Circulatory system: It consist of a contractike tube in dorsal side of the body through which the blood is pumped by rhytmic contractions.
- Respiratory system: Insects has a traqueal system. It´s an extensive network of thin- walled tubes that branch into every part of the body.
- The aquatic nymphs of dragonflies for example are equipped with traqueal gills.
