Insects are invertebrates that are found within the phylum of arthropods, that is, they have an external exoskeleton that provides great protection without sacrificing mobility and they also possess articulated appendages. They form the most diverse group of animals on the planet, with more than a million species, while many more are discovered every year.
On the other hand, they are mega-diverse and have adapted very well to almost every environment on the planet. Insects differ from other arthropods in having three pairs of legs and two pairs of wings, although the latter can vary. Its size can range from 1 mm to 20 cm, while the largest insects inhabit tropical areas. Continue reading this article on our site and you will learn everything about the wonderful world and the characteristics of insects, from details about their anatomy to what they feed on.
Anatomy of insects
The body of insects is covered by an exoskeleton made up of a succession of layers and various substances, among which is the chitin, sclerotin, wax and melanin. This gives them mechanical protection and protection against desiccation and water loss. As far as body shape is concerned, there is great variation within insects, they can be thick and plump like beetles, long and thin like phasmids and stick bugs, flattened like cockroaches. The antennae can also vary in shape, being feathery as in some moths, long in grasshoppers, or coiled as in butterflies. Your body is divided into three regions:
Insect Head
It's capsule-shaped and it's where the eyes, the mouthpiece made up of several pieces and the pair of antennae are inserted. The eyes can be compound, formed by thousands of receptor units, or simple, also called ocellus and it is a small photoreceptor structure. The oral apparatus is made up of articulated parts (the labrum, the mandibles, the maxillae and the labium) that allow them to perform different functions depending on the type of insect and its type of feeding, since it can be:
- Chewing type: as in the case of Orthoptera, Coleoptera and Lepidoptera.
- Cutting-sucking type: present in Diptera.
- Sucking type: also Diptera such as the fruit fly.
- Chewing-licking type: in bees and wasps.
- Picker-sucker type: typical of hemiptera such as fleas and lice.
- Siphon or tube type: also present in Lepidoptera.
Insect thorax
It is made up of three segments, each with a pair of legs:
- Prothorax.
- Mesothorax.
- Metathorax.
In most insects, the meso- and metathorax each bear a pair of wings These are cuticular expansions of the epidermis and They are equipped with veins. On the other hand, the legs are adapted for different functions depending on the way of life, since in terrestrial insects they can be marchers, jumpers, diggers, swimmers. In some species, they are modified to catch prey or collect pollen.
Insect Abdomen
It is composed of from 9 to 11 segments, but the latter is greatly reduced in structures called fences. The sexual organs are housed in the genital segments, which in males have a copulatory organ to transfer sperm and in females they are related to oviposition.
If you are passionate about these small animals, surely you will also like this other article on our site about The most beautiful insects in the world.
Insect feeding
The diet of insects is enormously varied. Depending on the type of insect, they can feed on the following:
- Plant juice.
- Plant tissues.
- Sheets.
- Fruits.
- Flowers.
- Wood.
- Fungal hyphae.
- Other insects or animals.
- Blood.
- Animal fluids.
Reproduction of insects
In insects, the sexes are separate and reproduction is internal Some species are asexual and reproduce by parthenogenesis, that is, by the production of unfertilized female sex cells. In sexual species, sperm are generally deposited in the female's genital ducts during copulation.
In some, the sperm are enclosed in spermatophores that can be transferred during copulation or deposited on the substrate to be picked up by the female. The sperm are then stored in the spermatheca of females.
Many species mate only once in their lifetime, however, others may mate several times a day. They generally lay many eggs, up to more than a million at a time and can be laid alone or in groups and do so in certain locations. Some species place them on the plant on which the larvae will then feed, aquatic species place them in the water, and in the case of parasites, they lay eggs on butterfly caterpillars or on other insects, where they will later develop. the larva and will have food. Also, in some cases, they can pierce wood and lay their eggs inside. Other species are viviparous and one individual is born at a time.
Metamorphosis and growth of insects
The first stages of growth take place inside the egg and can leave it in different ways. During metamorphosis, the insect undergoes transformations and changes shape, that is, they change their molt or ecdysis. Although this process is not exclusive to insects, very drastic changes occur in them, since it is related to the development of wings, restricted to the adult phase, and to sexual maturity. The metamorphosis can vary according to its type and are classified as follows:
- Holometabolos: that is, complete metamorphosis. It has all the stages: egg, larva, pupa and adult.
- Hemimetabolos: it is a gradual metamorphosis, here the states are: egg, nymph and adult. The changes occur little by little, and only in the last molt are they the most marked.
- Ametabolos: There is no differentiation between juveniles and adults, except for their sexual maturity and body size.
In this other article on our site we show you other Animals that undergo metamorphosis in their development.
Other characteristics of insects
In addition to the characteristics mentioned above, these are other peculiarities of insects:
- Tubular heart: they have a tubular heart through which hemolymph circulates (similar to the blood of other animals) and its contractions occur due to perist altic movements.
- Tracheal Breathing: You breathe through the tracheal system, an extensive network of fine tubes that branch throughout the body and that are connected to the outside by means of spiracles that allow gaseous exchange with the environment.
- Urinary system: they have Malipigian tubules for urine excretion.
- Sensory system: Your sensory system is made up of different structures. They have hair-like mechanoreceptors, they also perceive sound through tympanic organs that consist of a group of sensory cells. Chemoreceptors for taste and smell, sensory organs on antennae and legs for temperature, humidity, and gravity.
- They have diapause: they enter a state of lethargy where the animal remains at rest due to unfavorable environmental conditions. Therefore, its life cycle is synchronized with favorable times where food is abundant and environmental conditions are optimal.
- Defense method: for their defense, they have different types of coloration, and this can be warning or mimicry. Some species may also have a repulsive taste and smell, others have stingers with poisonous glands, horns for defense or stinging hairs. Some resort to flight.
- Pollinators: are pollinators of many plant species, which would not exist were it not for insect species. This process is called coevolution, where there is mutual adaptive evolution between two or more species.
- Social Species: Social species exist, and as far as this is concerned, they are highly evolved. They have cooperation within the group, which depends on tactile and chemical signals. However, not all groups are complex societies, many have temporary organizations and are not coordinated. On the other hand, insects such as ants, termites, wasps and bees are extremely organized, since they live in colonies with social hierarchies. They are highly evolved, to the point that they have developed a system of symbols to communicate and transmit information about the environment or a food source.
To complete our guide on insects and their characteristics, we leave you this other article on our site about The 20 most poisonous insects in the world.
