Arthropods Facts & Diet

Arthropods Species, Types, Facts, Diet, Habitat, Reproduction, Lifespan and list of Arthropods is here for you. Get all about Arthropods from this page now.

What is an Arthropod?

An arthropod is an invertebrate animal having an exoskeleton with a segmented body and paired jointed legs. They have the major role to maintain the ecosystem as recyclers of nutrients, pollinators, scavengers, and food for other animals. They are about75% of all animals on earth. It includes many animals that you look in your daily life such as spiders, centipedes, ants, and slaters. Arthropods are generally divided into four groups:

  • Insects
  • Myriapods
  • Arachnids
  • Crustaceans

arthropods image

The Arthropods developed before 530 million years ago in Cambrian oceans. These will able to survive today just because they adapt the change in environment during this long period.

Arthropod Definition

The invertebrate animals of Arthropods phylum having a segmented body with jointed limbs and a usually chitinous exoskeleton, continuous molted, including the insects, crustaceans, spiders and other arachnids, and myriapods.

Or any large group of animals with jointed limbs and a body made up of segments comes under the arthropod classification. There are few classifications of the arthropod that helps easy to recognize the arthropod class animals.

Arthropod Characteristics

There are several characteristics which divide the arthropod category from other class. The animals of class arthropod differs it from others. Here are the few characteristics of arthropod that helps you to distinguish other classes.


Arthropods are invertebrates which mean they have no bones in the body for support. They produce a hard exoskeleton made of chitin, a mixture of lipids, carbohydrates and protein that protects and covers their bodies like an armor suit.

Segmented Bodies

Arthropods bodies will be internally and externally segmented. The number of segments depends on the each species; for example, millipeds have more segments than lobsters.

Jointed Appendages

Arthropod is the Greek word in which ‘Arthro’ meaning joint, and ‘pod’ means foot. All arthropods have the jointed legs attached to their hard exoskeletons that allow the movement and flexibility. The joints generally bend in only one direction but allow for sufficient predatory and defensive actions.

Bilateral Symmetry

The arthropod’s body can be divided vertically into two mirror images. This is known as the bilateral symmetry. An arthropod shares this symmetry with many other animals such as mice, fish and even humans. The animals such as the jellyfish and sea star exhibit radial symmetry, but sea sponge and coral are asymmetrical or exhibiting no pattern at all.

Open Circulatory System

An arthropod has an open circulatory system. Instead of closed circulatory system of interconnected capillaries and veins, an arthropod’s blood is pumped through open spaces called sinuses to reach tissues.

Arthropods Examples

Arthropods are animals of the group of phylum Arthropoda. More than 80% of all animals in the world are arthropods. With such a large group of animals, there are lot of different species and examples – but they do have the some similar traits:

  • An exoskeleton or external skeleton made of chitin and it is covered with a thick protective layer which works as the armor suit.
  • Segmented bodies
  • Six legs or more which are jointed to the exoskeleton. Their name comes from the Greek words for ‘Joint’ and ‘Foot’.


Arthropods Facts

  • Yet Arthropods are not big, but according to the species numbers, it has the wide range.
  • The exoskeleton is water proof which makes it survive in the harsh conditions.
  • Arthropods like to be in the safe conditions because they are very vulnerable once they shed their exoskeleton.
  • Arthropods can survive in the harshest conditions across the world from very hot places to cold places in the world. A scorpion which is an arthropod, can survive even after being frozen solid.
  • Arthropods have no backbones. So, they are classified as the invertebrates.
  • The Arthropods were developed before half billion years ago.
  • Arthropods are often food for the animals and human beings as well. Commonly eaten arthropods are shrimp and lobster along with crabs.

Arthropods Reproduction

In the reproduction process of arthropods, there are both male and female individuals. The male sperm are commonly travels to the female within sealed packet that known as the spermatophores. In the process of transferring sperm are not diluted by the surrounding medium in the case of aquatic situation nor they will suffer this problem on the land for rapid desiccation.

The Arthropod eggs are usually have the rich quantity of yolk, but there are few species which eggs have little amount of yolk. This especially method of reproduction found in the certain arthropods include the evolvement of unfertilized eggs.

Types of Arthropods

The arthropods are generally divided in the three main groups:

Insects (Subphylum Hexapoda)

There are millions of inspect species exists all over the world. It’s best to just look at some of the common ones. All insects have well arranged paired six legs. They also have two compound eyes and two antennae on the head.

  • Aphids
  • Ants
  • Butter flies
  • Beetles
  • Cockroaches
  • Cicadas
  • Dragonflies
  • Leaf hoppers
  • Grasshoppers
  • Mayflies
  • Lice
  • Flies
  • Fleas
  • Stink bugs
  • Praying mantis
  • Termites
  • Silverfishes
  • Walking Sticks

Arachnids (Subphylum Chelicerata)

There are more than 100,000 species of arachnids. This class is divided into three categories.

  • Scorpionida
  • Acarina
  • Araneae

Arachnids have no wings and antennae with eight legged arthropods. Most of arachnids live on land but there are few species as well which found in the fresh and salt water habitats. Here are few names of species:

  • Brown Recluse
  • Crab Spiders
  • Black widow spider
  • Chiggers
  • Daddy longlegs
  • Harvestmen
  • Mites
  • Scorpions
  • Orb Weavers
  • Tick
  • Vinegaroons
  • Wind Scorpions
  • Whip tailed scorpions

Crustaceans (Subphylum Crustacea)

All crustaceans have ten legs and more which generally found in the living water. The majority of aquatic crustaceans live in salt water. But you can find several living in lakes and rivers. Woodlice are one of the small numbers of crustaceans that you can easily see on the land. There are 40,000 species of crustaceans. Here are few common ones:

  • Barnacles
  • Crabs
  • Brine Shrimp
  • Fish
  • Crayfish
  • Lice
  • Krill
  • Horseshoe Shrimp
  • Lobsters
  • Shrimp
  • Seed Shrimp.

arthropods facts

Are Insects Arthropods?

Yes, all insects classified under the category of the phylum Arthropoda. Here are few arthropods which share the various characteristics:

  • They do not have a backbone
  • They have exoskeleton made of chitin.
  • They have segmented bodies.
  • They have an open circulatory system.

All insects are arthropods, but all arthropods are not insects.

Are Spiders Arthropods?

Yes, all spiders are the member of the large category of animals known as the Arthropoda. The spiders have the characteristics to get in the class of Arthropods. The category includes smaller groups which follow the small groups or order. The spiders belong in the Order Araneidae which is the class of Arthropoda.

Are Crabs Arthropods?

Of course, it is. Crabs are coming under the category of the Crustaceans of phylum Arthropoda. The crabs have the exoskeleton and more than two-three pair of legs. The legs are jointed to the exoskeleton and their bodies are segmented. You can find the arthropod in water, land and air as well.

Are Ants Arthropods?

Yes, of course. Ants are Arthropoda which comes under the class of insects (Subphylum Hexapoda). Ants have the few pairs of legs and head with the exoskeleton and have the segmented bodies. The Arthropods have the millions of species which comes under this category.

Are Butterflies Arthropods?

This is true. Butterflies come under the class of insects (Subphylum Hexapoda). The butterflies fulfill the criteria to being in the Arthropod category.

Arthropod Exoskeleton

The arthropods have the exoskeleton which is tough and hard outer shell. It is mostly made up of chitin, which is the strong material related to the cellulose. It does not grow as the arthropod get bigger, unlike snail shells or turtle. The exoskeleton is the tough substance which has the arthropods to makes it stronger to survive in the tough and harsh conditions. The exoskeleton is made up of layers.

The harder outer layer and the more flexible inner layer work together to provide more protection against the predators. The innermost layer protects against the dehydration, and many arthropods have another layer that prevents the waxy layer to being damaged or torn. All these work together to provide the efficient system of protection.

Arthropod Habitat

Arthropods finds in the almost every habitat across the world. There are several species of the arthropods which lives even in the Antarctica. You can find the Arthropod in the water, land and air as well. The Arthropod has the millions of species under the category. There are many different species which adapt the environment in which they developed. So, the species of class arthropods can live on land, air, and water as well. There category animals will be able to survive in the harsh conditions. You can check more details about habitat of the Arthropods.

Arthropod Circulatory System

The Arthropods have the unique circulatory system. Their exoskeleton filled with the liquid body cavity, the haemocoel. Thereby, all tissues and organs are permanently exposed to a fluid medium known as the haemolymph. It consists of plasma with suspended haemocytes. The hemolymph circulation forced by the special pumping organ noted as heart. After go out heart, arteries and veins deliver the hemolymph to the various body regions and compartments. These arterial systems are developed to differing extents in arthropods and together with the heat constitute the haemolymph vascular system or the cardiovascular system.

Arthropods have an open circulatory system. It contains a dorsal heart and an arteries system that may be very limited in insects and extensive in crabs. The arteries deliver blood in tissues spaces from which it continuously drains back to a large pericardial sinus surrounding the heart. A number of Ostia (paired openings) are located along the length of heart and that allows blood to emit in when the valves are open. The closed valves prevent the blood to get back when the heart contracting and force it into the arteries of the tissues from which it flows to other hemocoels.

In the large crustaceans, the gills from which the blood will pass where it becomes oxygenated on its return to the heart. The blood of the large crustaceans and archinds contains the blue, because of the oxygen carrying pigment hemocyanin; insects lack a respiratory pigment since the tracheal system delivers oxygen directly to the tissues. Only a several insects have the hemoglobin in their blood such as some insect larvae and few small crustaceans.

Respiration in Arthropods

Aquatic Arthropods have the gills on their head for respiration. Although, they can varies in location and structure for the various categories. The gills are always outgrowths of the skin and therefore covered by the exoskeleton which is thin in this area and not a barrier to the exchange of gases. Terrestrial arthropods have the tracheae and book lungs as respiratory organs. Tracheae are the system of small tubes that allow passing of gases in the body.

In several species of arthropods, the tracheal tubes are bathed in the blood, but in insects tracheoles are embedded in the tissues, even within muscle cells. Tracheae are the undoubedly unique arthropod invention and developed number of times in the phylum. They are found in myriapods, insects, and arachnids. For small terrestrial animals, tracheal systems are highly efficient. The water loss reduced due to the small, external opening.

The chitinous lining prevents collapse, and the small size of the arthropod and resultant, tubule of short length eliminates the need of moving gases in and out by active ventilation. Book lungs are chitin-lined many blood filled plates over which air circulates contained by internal pockets. Most of the spider species have tracheae and book lungs, but large spiders such as tarantulas and scorpions have book lungs.

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