We get to see a great deal of diversity when it comes to bees, with 20,000 known species inhabiting the planet. There are so many different types of bees that it is a bit difficult to identify all of them with the naked eye. However, there are certain traits and characteristics which can help you in knowing the difference between some of the commonly seen bees. Honey bees These have a small shape. They are generally black. However, some have a brown-yellow center. These are extremely social in nature. A honeybee colony has three castes. One queen bee lays eggs. Some hundred drones are fertile male bees. Thousands of undeveloped female bees that are called worker bees. The job of these workers is to collect nectar from flowers, make and store honey, protect the hive, feed and care for the queen bee and the baby honey bees. Their sting is barbed and cannot be withdrawn. The hives that honey bees build are called 'honey combs' or 'beeswax'. The wax is generated due to the special glands in the abdomen. Honey is stored in the hexagonal cells of the beehive. The pollen is carried in a smooth, bristle-surrounded area on one segment of the hind leg. This is called a pollen basket or corbicula. Ground bees These dig tunnels in the ground and hence are also called "mining bees". These tunnels are made with the aim of providing shelter for their progeny. Well-shaded areas having loose soil and scarce vegetation is chosen. Chambers are made at the end of the tunnels by female bees. Here, they store food for the baby bees. The ground bee is black in color, small in size and can sting. Normally, they are not aggressive. However, when they feel threatened they can attack. Pollen is carried on the body and leg hair. Bumblebees These are large and hairy. The general color is black and yellow. These display social behavior and live in colonies. In tropical areas, these colonies flourish for many years. In temperate areas like North America, the worker bees and drones perish in cool climate. The young and fertilized queen bees survive the winter due to hibernation. When the temperature elevates, these lay eggs to start a new colony. In tropical regions, there are some varieties of stingless bumblebees. This species live in deserted holes made by rodents and other small animals. Digger bees They have long tongues and fly very fast. These excavate nests in wood or stay in the ground solitary or socially. Pollen is carried on brushy areas close to the middle of the hind leg and are excellent pollinators. Around thousand species of digger bees can be found in Canada and America. These are also characterized by the exceptionally long antennae of its male members. Another characteristic is that these are not overly aggressive and their sting is milder when compared to other bees. Carpenter bees These have metal-like, black color and no yellow marks. Their length is 2 to 2.5 inches. They have solitary behavior and cannot prepare wax. From flower to flower, they can travel long distances. The nests these make are in flower stalks or wood. There exists a pile of sawdust near the nest entrance. Cellophane bees As these are similar to wasps, they are considered to be the most primitive bees. These have short and forked tongues and are relatively hairless. Their nest tunnels and larval cells are created with a secretion that becomes as hard as a cellophane membrane. Pollen grains are carried on leg hair or internally in a stomach like crop. Orchid bees They are brightly colored and are metallic in appearance. It is thought that orchids and orchid bees co-evolved and hence they are dependent on each other. They have a long proboscis and store the nectar very deep within their blossoms. These are one of the few species where males are engaged in productive activity other than mating. Males gather fragrant oils from blossoms by employing the scraper-like segments of the legs. It is guessed that these oils are used to attract mates. Africanized honey bees These were found all over Africa, south of the Sahara desert. As per one ideology, they migrated to North and South America in 1956 and stayed in the rural regions. Another theory states that, African honey bees were imported to Brazil in 1957 and subsequently released into the wild. These mated with European honey bees and the progeny was called "Africanized honey bees". These are similar to European honey bees, but they are more aggressive to defend their nests. So, they are called "killer bees". From Brazil, they spread to South and North America. When people and animals are in the vicinity of their nests, these bees are very dangerous. Similar to the honey bees, they produce honey and pollinate plants. Their social features are akin to the honey bee. Leafcutter and Mason bees These prepare their nests in preexisting cavities or live in collections of individual nests. They have long tongues and special pollen carrying hair on the bottom side of the abdomen. They are useful in agriculture as they pollinate crops. Sweat bees While the technically sound use of the term 'sweat bees' is restricted to species belonging to family Halictidae, colloquially it is used for all the bee species which are attracted to the human sweat - the salt in the human sweat to be precise. These are small, dark-colored bees with little hair, which build their nests on the ground. They have societies in which related individuals assist one another. Pollen is carried on body hair and base of the legs. Parasitic bees These are also called "cuckoo" bees. These do not search for food or build nests on their own. Instead, they use the nests and food of other bees. They can be classified into "cleptoparasitic bees" and "social parasites". The former attack the nests of solitary bees, hide their eggs in the chambers before the host lay their own and close the chambers. The baby bees flourish on the food stored by the host female. The eggs or larvae of the host female are killed by the parasitic female or her larvae. The social bees kill the queen bee, lay their eggs in the cells of the host and coerce the workers of the host to rear their babies. Females of parasitic bees do not have pollen brushes or pollen baskets. At one end we the smallest bee in the world, Trigona minima, measuring mere 2.1 mm. At the other, we have the leafcutter bee measuring 39 mm. In between these two, there exist as many as 20,000 species of bees which come in a range of sizes and colors. It is difficult to find a better example of diversity in kingdom Animalia.