Bees and wasps are cousins -- they belong to the same family of insects -- but at the same time they can be deadly enemies. All bees have wings while some wasps are wingless, but when they have wings, they are same kind. Bees are important pollinators, but so are some wasps. Not all bees sting, but neither do all wasps; when they do sting, the bee dies while the wasp lives to sting again. Some wasps eat meat -- usually other insects -- but bees feed only on nectar and pollen. Overall, both bees and wasps are an important part of the planetary ecosystem.
Both bees and wasps belong to the insect family Hymenoptera, meaning "thin membranous wings." They don't all have wings, but when they do, they have two pairs and the front ones are larger than the back ones. Ants and hornets are also part of this insect family, which has 120,000 named species to date.
Like all insects, bees and wasps have six legs. Bees have a thick body, while most wasps show the classic narrow or "wasp-waisted" connection between thorax and abdomen. Both bees and wasps have mandibles, or chewing mouth parts, but in bees these are partially modified into a tube for sucking up nectar. Both may have a lot of body hair or only a few hairs, but the bee's are branched while the wasp's are simple -- you need a microscope to see this.
Most wasps are predatory carnivores, eating mostly other insects in all stages of development. Bees are vegetarian, eating only nectar -- which they concentrate into honey and store in their hive for winter food -- and pollen. Bees are a favourite prey of one member of the wasp group, the Asian giant hornet, which will attack beehives, kill the adult bees and carry off the larvae to chew into paste and feed this to its own offspring.
Defending the Nest
Since bees do not attack wasps, wasps need no defence against bees. The Asian giant hornet does attack bees, though, and the European honeybee (Apis mellifera) has no defence against it. Asian honeybees (Apis cerana), however, have developed a way of defending their hive against predatory hornets -- they mob an attacking hornet and cook it by surrounding it with a cluster of their own bodies. They do not sting it to death, but instead vibrate their muscles to generate heat until the temperature inside the ball of bees rises to 46.7 degrees Celsius or more, which kills the hornet.