How does a honey bee develop from an egg to an adult?:
The honey bee queen lays an egg in a small chamber or cell in an area of the colony called the brood nest. A helpless, grub-like larva emerges from each egg after a few days, and its only function is to eat. Unlike a butterfly caterpillar that must forage for food, the bee larva never strays from its cell and nurse bees (young adult worker bees that perform this task at a partic-ular stage of their life) constantly eliver food, sometimes flood-ing the cell with food. It has been estimated that more than one hundred thousand visits are made to a single honey bee during its egg and larval stages, during which time the larva can in-crease in size one-thousand-fold (see this chapter, question 2: What do larvae eat?) Because it doesn’t leave its cell, the larva’s bodily wastes are stored inside its body to protect the food in the cell from fecal contamination.All honey bees outgrow their “skin” and molt about every twenty-four hours during the first few days of larval life. Their skin is actu-ally an external skeleton or xoskeleton,and when the ecdysisor molting occurs, the skin splits at the head and slips off the rear end of the larva’s body in a process that normally takes less than thirty minutes. Underneath is a new skin that is softer and looser at first, filling up as the larva grows until it is stretched tightly Metamorphosis Bees undergo complete metamorphosis, which involves a sig-nificant change in both their internal and external form (mor- phology).The word is from the Greek word metamorphoun, meaning “to transform,” a compound of the words meta(after or beyond) and morphe(form). The familiar transformation from a tadpole into a frog is another example of complete metamorphosis. Complete metamorphosis in an insect involves four basic stages: • It starts with an egg containing an embryo. • A bee larva hatches from the egg, basically a simple grub-like eating machine that outgrows and sheds its outer skin five times. This process is called molting, and the skin is actually its skeleton, called an exoskeleton. Each time the old exoskeleton is shed, a new, looser version is revealed underneath that fills up as the larva eats. A complicated series of hormonal fluctuations accompanies each molt. • The fully grown larva’s last molt reveals the pupal stage, during which the exoskeleton totally encloses the insect and it stops eating. Within the pupa, the bodily structures reorganize, unnecessary body parts are discarded, and the insect is totally transformed. • A fully grown adult insect emerges from the pupa.About 12 percent of insects, including crickets and grass-hoppers, go through incompletemetamorphosis that skips the pupal stage. The adult female lays her eggs and the eggs hatch into nymphs that look like small adults but usually don’t have wings. They molt several times as they grow until they reach their adult size, by which time they have usually grown wings. In contrast to metamorphosis, a cockroach and a human are examples of a continuously developing animal that begins as a small version of its adult self and just grows larger, the only structural change being the development of its reproductive organs and, in insects, fully developed wings. again, signaling that it is time for another molt. Each stage before the molt is called a numbered instar, and after the fourth instar has grown to its maximum size, several things happen. Prompted by hormones (internal chemical changes) and phero-mones (external chemical signals), the larva stops eating and finally expels its feces, which are pushed down to the bottom of the cell. The nurse bees apply a wax cap that closes off the cell, and the larva spins a cocoon around itself using silk from a special gland in its head. Layers of silk may coat the brood cell walls, having accumulated from previous larval generations. The beeswax that makes up the combs can soften in warm weather, and the accumulated silk is thought to strengthen the cell and give extra protection to the pupae. Soon after the cocoon is complete, the fifth molt occurs inside the cocoon and the pupa is revealed under the old exoskeleton. During the pupal stage, the larva metamorphoses into a fully grown adult bee. When the metamorphosis is complete, the bee ecloses, which means it sheds its cocoon, and then finally leaves the cell to begin its adult working life. Beekeepers sometimes describe the emergence of the adult bees from the pupal case as “hatching,” a colloquial term for eclosing. The length of each developmental stage differs slightly for each caste, although each caste spends about three days in the egg. The queen spends eight days as a larva, and after about four days in the pupal stage she ecloses. Female workers spend about eight to ten days as larvae and eight days as pupae. Drones spend about thirteen days as larvae and eight days as pupae.

What do larvae eat?:
Nursing worker bees bring the larvae a series of different foods as they develop in their cells. At each stage of growth, the larvae give off particular chemical signals (phero-mones) that tell the nurse bees what to feed them, resulting in qualitative and quantitative differences in the food given to lar-val queens, workers, and drones. The larvae that will develop into worker bees are first fed a brood food,also called worker jelly, which is produced by the hypopharyngeal gland in the head of a nurse bee. After about six days, the nurse bees begin feeding the worker larvae a combination of nectar and bee bread,which is a substance made from pre-digested protein-rich pollen. After three more days, the larvae enter the pupal stage, at which time they stop eating and live off their accumulated body fat, and over the next few days they metamorphose into adult bees. The bee larvae that will develop into queens are fed exclu-sively on royal jelly for their first four days of life .Drone larvae require the most food because they grow larger than either workers or queens, and the food mixture given to older drone larvae contains the most protein-rich pollen. Other species of bees have a different way of feeding their young. In solitary species there are no nest mates to care for the young. Instead, the mother prepares a nest in soil or in another small space and she places a small pellet of pollen mixed with freshly collected nectar in the nest. She lays one egg directly on this larder, and when the larva emerges it eats this food inde-pendently, without any contact with adult bees. It subsequently pupates, metamorphoses, and emerges as a fully developed adult bee.

Does a bee have a heart?:
Yes, bees have hearts, but they are quite different than the four-chambered hearts of mammals like humans. Bees, like all insects, have an open circulatory system without veins or arteries, so there are places in its body where the body fluid (hemolymph) washes directly around the tissues and organs. A pulsating, muscular tube along its back, called the dorsal vessel, pumps the hemolymph from the abdomen to the thorax and then to the head, squeezing the hemolymph into each section of the body. Additional pulsating organs, called simple hearts, or ostia, are located at other points in the body and boost the fluid’s circulation. As the muscles relax, the fluid circulates back into the dorsal vessel, moving more or less quickly depending on the insect’s activity level. Unlike blood, hemolymph does not carry oxygen, so this relatively inefficient system is adequate to distribute nutrients to the cells.

How do bees breathe?:
Bees breathe without lungs. Air enters through open-ings called spiracles on the sides of the bee body, and a net-work of tubes called trachea weave their way around organs and through tissues, allowing air to ooze throughout the bee’s body. For larvae and inactive insects, this is how they breathe, tak-ing in oxygen and expelling carbon dioxide through this simple system. But when a bee flies, it needs more oxygen and its flight muscles move more air through its body by expanding air sacs that are part of the respiratory system and drawing air in more forcefully. Then the spiracles contract and compress the air sacs, forcing the air deeper into the body so that more oxygen reaches the cells, and then the spiracles open and carbon diox-ide is expelled.

What did honey bee see ?:
Like many insects, bees have more than two eyes they actually have five. The two largest are compound eyes that are set on either side of the head, each containing 4,500 indi-vidual hexagonal facets (ommatidia), which are light sensitive units that work together to produce an integrated visual image, although what they see is different from what we see. According to Lars Chittka and Nigel Raine at the University of London, the clarity of their vision is approximately one hundred times worse than normal human vision. This is because the number of ommatidia is relatively small compared to the 1.5 million photo-receptors in the human retina or the millions of light-sensitive elements in a digital camera. Susanne Williams and Adrian Dyer at Monash University in Australia created an optical device that simulates the way mul-tiple lenses create an image by using 4,500 parallel-mounted black drinking straws. Using this device, they concluded that in order to see fine details, bees would have to be very close to an object. Color plate D shows how, using their device, they illus-trated what a flower might look like to a honey bee. Later work from the same lab applied this imaging system to the under-standing of how bees navigate and recognize complex natural landmarks with incredible accuracy. The bee’s other three eyes are simple structures, called ocelli, that are located on the top of its head. These are light-detecting organs that do not produce visual images. They are common in some other insects; for example, some butterflies have ocelli on their genitalia. It is thought that they help the bee sense direc-tion and low levels of light, and they may play a role in enabling bees to follow a streaking scout bee that flies overhead to lead a swarm to its new home . Bees are also able to see fast-moving objects much better than we can, and the ocelli may play a role in this facility. Recent experiments by Gerald Kastberger at the University of Graz in Austria explored how bees with oc-cluded ocelli react to changes in the light environment during flight. He found that the ocelli seem to help control phototactic behavior in flight course control in honey bees. Adrian Dyer has done a series of interesting experiments to explore the limits of bee vision. After much trial and error, he trained honey bees, Apis mellifera,to recognize an image of a human face by associating that face with a sugar reward, and they consistently flew to the familiar face when it was placed with other images that were unfamiliar. They even flew to that face when the sugar reward was removed. But when the face was rotated 180 degrees, they were significantly less able to identify it, raising interesting questions about their visual processing. Bees are partially colorblind. Each ommatidum or facet in the eye contains nine light-sensitive cells that are receptive to dif-ferent colors. They contain six green receptor cells, according to Motohiro Wakakuwa at Yokahama City University, which are responsible for detecting motion and seeing small targets. The other color receptors vary depending on their position in the eye, and there are now understood to be three types of omma-tidia. So, for example, if the bee is looking down, certain recep-tors are sensitive to green light, but if she is looking up, they are sensitive to ultraviolet. The brain apparently compares complex sets of signals from different sensors to identify color. Experiments have demonstrated that honey bees can see a wide range of colors, but the spectrum visible to them is shifted into the ultraviolet range, so they can tell the difference between yellow, blue, green, and ultraviolet but cannot distinguish be-tween red and black. They can also see a color, known as “bee’s purple,” that is a mixture of yellow and ultraviolet, and they can see patterns of polarized light that help them navigate . Rudiger Wehner and Gary Bernard demonstrated that most photoreceptors in a bee’s eye are “twisted like a corkscrew,” and they found that the amount of the twist corrects for the po-tentially false perception of colors as a result of polarized glare from reflecting surfaces on plants.The interior of a bee colony is quite dark and yet the bees in-side do all sorts of detailed work, so clearly bees can “see” in the dark; touch and scent play a large part in organizing their ac-tivities inside the colony. Because they are red/black colorblind, meaning they cannot distinguish between these two colors, ob-servation hives and bee labs are commonly lit with red lights so that researchers can watch them while the bees carry on in what seems like normal darkness to them.

Did honeybee has bones?:
Instead of a bony internal skeleton, adult bees, like all insects, have a firm scaffolding, called an exoskeleton,that encases the outside of their body. The external covering hardens after the bee emerges from the pupa, and it protects the bee from drying out, gives the bee support, and allows for movement. All of the bee’s muscles are attached to this exoskeleton, which is jointed but very solid and durable. It is also coated with a thin layer of oily wax, secreted by the bee, which has an odor that is unique to her particular hive. Guard bees use these odors to compare to sensory information from the colony to determine if a bee trying to enter the colony is a nest mate or an intruder.

What are the antennae used for?:
A bee has two antennae, sometimes called feelers, and the name “feelers” describes what these appendages do for bees. Each antenna is a major source of environmental informa-tion, with sensors that detect odors and function as giant ex-ternal noses. Other antennal sensors are mechanosensors that detect wind direction and pressure waves, including vibrations, and they help the bees stay attuned to their body position in the environment. Using a microscope to examine the honey bee antenna reveals the complexity of these sensors.