Bioterrorism Targeting Animals

Bioterrorism Targeting Animals by Andrea Evans

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What is Bioterrorism?

When people hear the word “bioterrorism” they generally associate it with a biological attack directly targeting the human population. Bioterrorism can be defined as the deliberate release of viruses, bacteria and other germs used to cause illness or death in people, plants, or animals (CDC 2007). We seem to ignore all of the indirect threats such as plants and animals that can greatly impact the society if targeted.


 Bioterrorism Targeting Animal Agriculture

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A specific form of bioterrorism is bioterrorism targeting animal agriculture. This form of bioterrorism involves terrorists targeting livestock such as cows, pigs, sheep, etc. in order to indirectly impact their enemy. This presents a problem for those involved because by targeting animals, terrorists are able to not only spread disease, but also are able to impact their targets economy severely. People began using animals to target their enemies since the 14th and 15th centuries. They did this by catapulting rotting animal corpses over into their enemy’s home base. People of that time were able to associate a rotting animal corpse with some sort of biological infection. Today, there is a much better understanding of biology which allows terrorists to utilize it in bioterrorism attacks.


 Why Is The United States A Major Target?

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The United States is currently the largest distributor in the world of livestock. The United States is the source of many countries food supplies throughout the world. Given that the United States is the leading distributor, much of our growth in economy comes from the distribution of livestock (Olson 2012). The United States is a major target in a bioterrorism attack because if the United States must halt its distribution, they will lose all of their connections to other countries. If the United States were to be under a bioterrorism attack on their livestock, the U.S. would not be able to distribute. This would significantly impact the U.S. economy as well as potentially cause the U.S. to lose its distributing connections with other countries.


What Types of Disease Are We Talking about? 

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 Anthrax: Anthrax is a lethal disease affecting mostly animals caused by Bacillus anthracis. Anthrax is capable of being contracted in the skin, lungs and gastrointestinal tract. Animals are capable of spreading this disease to humans, but humans are incapable of spreading this disease to each other. Sources of anthrax can be from body wastes and carcasses of infection animals and can easily be accidently handled or ingested by humans, further spreading the disease (Liu et al. 2013).


 

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 Foot-And-Mouth: Foot-and- Mouth (FMD) disease is a lethal disease targeting the hooves and mouths of animals such as horses and cows. FMD is caused by the bacteria Aphthae epizooticae. This bacteria is extremely hard to vaccinate against because it variable, coming in many different forms. This viral disease is easily spread from animal to animal and causes a major threat on animal farming. Animals infected with this disease are incapable of be utilized as an agricultural source due to the infection.


 

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Avian Influenza: Avian influenza is most commonly known as the bird flu caused by the influenza A virus. Most avian influenzas do not infect humans, but overtime some have developed the capabilities of infecting humans. Avian influenza has a major impact on poultry populations and can cause a decrease in production. Once a bird has a confirmed case of avian influenza, surrounding birds must be killed and the infection sites must be sanitized to decrease further spreading of the influenza. This form of sanitation is called depopulation. Depopulation is a method of quickly destroying a large number of animals in order to prevent further spreading of a given infection (Martcheva 2014). In order to manage and maintain spread of avian influenza, proper protocols must be followed.


What Can We Do To Prevent it?

 Prevention from a bioterrorism attack on agriculture requires an increase in security at major farming locations. Daily, animals are taken in and out of distribution warehouses and put into contact with thousands of animals. Increasing the security and maintenance of animals being brought in and out of facilities will help prevent diseases from getting into livestock distribution warehouses. We can also prevent major bioterrorism attacks on livestock by following proper protocols when an infection hits. This includes proper depopulation of all animals infected.

 

References:

Liu, S., Y. Zhang, M. Moayeri, et al. (10 co-authors). 2013. Key tissue responsible for anthrax-toxin-induced lethality. Nature. 501: 63-68.

Martcheva, M. 2014. Avian flu: modeling and implications for control. Jour. Bio. Sys. 22: 151-175.

Olson, D. 2012. Agroterrorism: threats to America’s economy and food supply. FBI Law Enf. Bull. 81: 1-1.

Farming Shellfish for the Greater Good

When someone hears the word farming, that someone might picture a person dressed in overalls, wielding a pitchfork, and driving a tractor around big open land. What most people don’t think of is aquaculture farming that happens in the water. Along with those delicious berries and greens you find in the grocery store, much of the shellfish such as oysters and clams are also farmed.

There are not many environmental benefits for land farming except to buy food for dinner. Shellfish farming does more than give us some dinner. Shellfish farming, also known as shellfish aquaculture, can help clean the water that humans throw their waste into. Many humans love a good oyster every now and again but we are not the only living organism that enjoys oysters. By farming shellfish, the farming creates a food source for other marine animals such as birds. Some objects that are beneficial to this world are made through a process that actually hurts this world with pollution. The gear that is needed to farm shellfish is also beneficial to the surrounding environment. The gear creates a shelter for other marine organisms such as fish to take refuge from predators.

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These shellfish can be farmed in a few different ways. One way is to set up long lines that hang down from the surface of the water and shellfish such as oysters or clams grow on the suspended lines. These can be set up in a controlled area or in the open water. Another method of farming shellfish is to have an environment where the salinity and temperature is controlled and constant and to drop bags or cages and have the shellfish grow in the cages under water. The bag or cage would be brought to the surface to harvest the mature shellfish. Shellfish aquacultures that are set up in the ocean with changing environmental conditions such as temperature and salinity is beneficial to the quality of the water that is polluted every day.

Humans throw a lot of waste into the water. Whether it is driving a power boat around or factories that dump their nitrogen filled waste in the water, this waste is harmful to the surrounding water. A group of shellfish called bivalves, which are a compressed body surrounded by a shell such as an oyster, can filter the water to remove some of the excess nitrogen that humans carelessly dump into the big blue ocean. Bivalves can filter an amazing amount of water in a day. In some species, individuals can filter up to 50 gallons of water per day. Most shellfish farms have thousands of bivalves growing, so if you add it all up, that is a large amount of water that is getting filtered in just one day. The excess nitrogen dumped into the water can actually be beneficial to the bivalves because they use it for their tissue growth.

Oysters served in a buttery, garlic sauce is a favorite dish to many seafood lovers. We are not the only ones that enjoy good seafood. Some species of birds love a good shellfish meal. The shellfish may not be soaked in a fattening, tasty sauce, but some birds still love them as much as humans do. There are species of sea ducks in France that came back to an area that people thought they left for good, because of shellfish farms. These farms created an abundant food source for these birds. Sea ducks in France are not the only bird that likes to eat shellfish. There are many marine birds in the US that will crack open a bivalve and eat the delicious meat inside. Shellfish farming is growing in many areas around the world and the continuous growth will create food for many different organisms.

The process to make many of the material objects in this world is harmful to the environment including the water. There are even some farms that create food for people to eat but also spray pesticides everywhere that does harm other animals. When it comes to shellfish farming, the gear and equipment that the shellfish farms rely on are not harmful to the environment. The gear is beneficial in many ways. The equipment can create a shelter for little species of fish to hide if they are getting chased by a predator. The gear can also create a place for scared fish to eat in peace and not have to worry about another fish sneaking up behind them and stealing their food or using that scared fish as food.

Next time someone says the word farming, remember that a shirtless person in overalls planting seeds is not the only farmer in this world. Shellfish are becoming a big product of farming and is very beneficial to the human’s race and to other organisms that live in or around the water.

Save the Penguin, Save the World

Climate change, also known as global warming, is an increase in the world’s surface temperature or sea surface temperature. The rapid increase in temperature will severely affect the inhabitants of polar regions. For example, polar bear and some seal populations are projected to lose a great deal of their habitat by the year 2100. Penguins are also among these at-risk animals as they are a group of animals that rely on a specific temperature that assists in their way of life. The penguin population is in danger due to their sensitivity to climate change, which will ultimately affect their reproduction schedules, food sources and migratory patterns.

The Adelie penguins are primarily found living in icy areas, and are known as ice obligate creatures. Their breeding process is partially dictated by how long the days are. As the days get longer, these penguins produce hormones that change their behavior. This will lead to an increase of their fat storage, which is required for the extended periods of time during migration. Because timing is influenced by length of day, if temperatures are altered it will not only affect their breeding schedule, but also general survival of the species. Breeding is also dictated by how precise their environment is. Having an altered environment can affect the arrival, body weight and nutrition before breeding, as well as timing of egg laying and egg size. Specifically speaking, if the seasons turn to summer and the days get shorter, the urge to breed lessens (Ainley 2002). After their storage of food, the penguins begin a fasting period and couples form a bond where they create offspring. The female lays exactly two eggs and incubates them for a little over 30 days before she trades off with the male penguin. Any alteration to this process can negatively affect the future generations of penguins. If there is a delay, the Adelie’s will not be able to complete their post breeding migration. If they are not able to complete this process, their molt will not be on time therefore trapping them on solid ice, which can cease breeding for the following season.

Emperor penguins are a type of penguin that breed based on a very specific schedule; therefore are subject to climate change. The male and female penguins take turns going off to feed, then travel 60 to 100 miles to nest and breed in the month of May. They only produce a single egg in the summer months of June and July and the male incubates it until it hatches in August. After the babies are hatched, their feeding begins in fall between September and October. There is concern that chicks hatched late in the season will not have the time needed to fully develop. The Emperor penguins’ wings have three layers containing dense, oily and water-proof feathers that allow them to swim efficiently.   If they are not given time to mature properly, the chicks may not develop the protection they will need as time goes by. Due to the exactness of this schedule, if the sea surface temperature were to increase, it can put at risk the single egg from reaching adulthood.

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The Adelie penguins and Emperor penguins share a specific diet consisting of small fish and krill. Often humorous, this process consists of them clumsily tripping over ice and snow mounds, making their way to an opening in the ice, where they dive into the water to eat. Krill are a small, shrimp-like sea creature that tends to deposit closer to pack ice. Pack ice, also known as polar ice caps, are larger pieces of ice drifting on the water. Increased sea surface temperature will lead to reduced amounts of pack ice which the krill require for a safe haven to reproduce and live. This in turn will lead to a decline in a major food source for both of these types of penguins. The other small fish that the penguins consume are also at risk, as the krill are a major food source for many parts of the food chain.

The Adelie and Emperor penguins are not the only breed to be affected by climate change; there is also the Fairy penguin. Appropriately named, Fairy penguins are the smallest species of penguins. Luckily, they have shown to adapt quickly to forced change. In 1982, six penguins were taken towards the end of their molting period and had interaction with humans. During this period, they were exposed to a change in diet over differing temperatures throughout the changing of seasons. The data showed that there was a correlation between egg laying rates and sea surface temperature. It also leads to lower breeding successes between generations.

The Adelie, Emperior and Fairy penguins all have a similar characteristic; they are victims of climate change. They all have a regimen that is being compromised and can eventually lead to their demise. Food consumption, migration patterns and reproduction are all essential to their way of life. The krill that they eat are also at risk due to change in sea level. Migration patterns will change due to a rise in temperature. There is hope that some species will be able to adjust to the climate changes, however there is no telling what the future will hold.

Citations:

Ainley, D. 2002. The adelie penguin. 1st ed. Columbia University Press, New York, New York.

Humpback Whales: Masters of Sound and Show

Whales, along with dolphins and porpoises, are very social animals, with some living in pods, or a group of whales, for their whole lives. One of the most well-known whales is the humpback whale, or Megaptera novaeangliae, or literally “New England big wing”, known for its complex songs and large flippers. Here is a little context on these whales. Humpbacks, like most mysticetes, or baleen whales, do not live in pods for extended periods of time. However, they do form pods when traveling to and from their winter breeding grounds. These whales are known to be very curious creatures, making them excellent for whale-watching; this often makes them change their communication patterns in different, even bizarre ways. Humpbacks use a foraging strategy that is exclusive to their species known as bubble-netting, where they use bubbles to concentrate their prey into a position that is convenient for feeding. Among whales, humpbacks have one of the most complex communication capabilities, as well as the most diverse behavior, in the animal kingdom. I will be discussing their songs, a type of sound known as megapclicks, their pod and surfacing behavior, bubble netting, and their innate curiosity.

Humpback whales are most well-known for their songs, but they also have a large repertoire of other sounds, including moans and grunts. A song is, in the biological sense, nothing more than a string of sounds that are produced in a repetitive fashion. The songs humpbacks sing are, in my honest opinion, better than any song that is played on the radio today. Humpbacks use these songs during the mating season, but the exact purpose of these songs is unknown, as is true with much of the behaviors that humpbacks use. We do know that whales will change the structure and composition of their songs due to coming in contact with other pods. We also know that humpbacks will shorten their songs in the presence of ships; however, we are not sure why they do this. It does make studying their songs really hard to do, since we usually need to use ships to study their songs at all.

Among the humpback whales’ immense collection of sounds is a sound known as a megapclick, a clicking sound named after the scientific name of the humpback, Megaptera novaeangliae. Megapclicks are used during nighttime foraging. These sounds were just discovered recently, so we still do not know the purpose of these sounds. We do know that these sounds are somewhat rare, only being heard twice throughout the continual study process. Some people, including myself, believe that it may be a form of echolocation, similar to what odontocetes, or toothed whales use.

Humpback breaching image

As mentioned previously, humpbacks rarely form long-standing pods. That does not mean that they do not exist. When in pods, these whales will perform in behaviors that are generally well-known, including breaching, in which at least 40% of the whale clears the water’s surface. They communicate through a set of behaviors known universally as surfacing behaviors, many of which, including breaching, are well known. We do not know why humpbacks, or any whale for that matter, will perform most forms of surfacing behavior; we just know that they will use these behaviors when they are in groups. Some scientists, and many people, believe that it is just their way of having fun.

Bubble net image

Bubble-netting is another humpback exclusive behavior. Humpbacks will swim below a school of fish and, as they rise, blow bubbles by producing sounds, corralling the fish into a concentrated area. These bubbles scare the fish into the correct position to maximize the amount of fish caught in one lunge. Some humpbacks prefer to use true bubble nets, where they produce bubbles that form spirals going around in a circle, or bubble clouds, which are collections of small seltzer-like bubbles meant to stun or disorient fish. When multiple humpbacks forage together, this foraging technique becomes much more efficient, as the whales will take turns “casting the nets,” as it were, so everyone gets the chance to eat fish. It is unclear how the whales thought of this unique strategy, but it is clear that it works.

Humpback whales are the most curious of all whales, often approaching ships by themselves. During the days of commercial whaling, this often led humpbacks to their death, earning them the title, “the stupidest of all the whales”. These whales are very unique in that they will act very differently when they are around people than when they are by themselves, which makes direct observations on their behavior nearly impossible. These whales, like dolphins, are highly intelligent, so they may just by trying to mess with the heads of the scientists trying to study them.

Humpbacks are very vocal and expressive creatures, traveling the world’s oceans. On the international scale, these majestic animals are endangered, or at risk of dying out forever. These whales need our protection if they are to survive for future generations to enjoy. If you want to see these majestic creatures yourself, you can easily see them by going whale-watching in the summer and fall, and all you need is a good pair of binoculars and a camera.

Why You Should Care About Algae Bioreactors

Why Should You Care About Algae Bioreactors?

Whether you believe a changing climate is manmade or not, renewable and sustainable means of energy production should be on your radar. It is simply not a sustainable model to continue to use fossil fuels at the rate humanity is right now. One day, the reserves will run dry and our ability of acquiring energy could prove to be much more challenging. Renewable energy systems offer more security and economic independence from other countries because we will not be relying on foreign oil. Also, renewable energy technologies could allow us to be free from oil-related conflict. Some of the current means of renewable energy production are solar, wind, and wave; however, microalgae bioreactors offer a new method of producing energy in a sustainable manner.
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Algae bioreactors work through photosynthesis. This important naturally occurring biochemical process is used by all plants, and without it more carbon dioxide would be built up in the atmosphere and there would be less oxygen available for us to breathe. Photosynthesis uses sunlight to break down carbon dioxide and water to create glucose (a form of energy also used by the human body) and oxygen. The glucose, or resulting biomass, that results from this process can then be used as fuel and burned. This ability to produce fuel is partly what makes algae bioreactors so promising and exciting. Because the bioreactor system is using carbon dioxide that is already in the air, when the product is burned it is essentially the same carbon dioxide being released again. This means that no additional carbon dioxide is being produced. That carbon dioxide will continue to go through the cycle of being taken up by the algae and being released when the biomass is burned. This makes microalgae bioreactors carbon neutral. Fossil fuels on the other hand, have been stored in the Earth’s crust for millions of years. This means that the chemicals produced by burning fossil fuels are being reintroduced to Earth’s cycles. So when burning fossil fuels, we are putting something back into the atmosphere that has not been there for millions of years, and this shifts the current balance of the atmosphere. It is important to realize, that once the atmosphere was very heavy with carbon dioxide, and this is likely not a condition that could sustain human life.
Algae bioreactors are multifunctional because they can be designed as open or closed systems. Open systems are like ponds or fountains, while closed systems are encased in transparent materials like glass. Due to the ability to be open or closed system, algae bioreactors have found a variety of different uses. They can theoretically be used in public spaces like fountains to control carbon dioxide levels, and even produce useable biomass which is stored beneath the system. Algae bioreactors can even be used to provide hydrogen to fuel cells which are incredibly efficient units that currently use fossil fuels.
Perhaps one of the most promising fields for algae bioreactors is in civil engineering andErstbefuellung Algenhaus Wilhelmsburg architecture. Algae bioreactors can actually look very beautiful in contrast to the cold grey metal we are familiar with in many modern buildings. While algae bioreactors are still fairly new, they are already being integrated into building facades and can provide the building with heat and running water. The photo to the left shows a new construction in Hamburg, Germany which is the first residential building of its kind to use algae bioreactors in this way.
Additionally, algae bioreactors can produce biofuel to meet a variety needs. Currently, biofuels are a more controversial matter because the lands used to grow the required crops are areas that many believe should be used for food production. The problem is that these traditional crops like corn will only grow during one season, and food is more essential to sustain life than energy to power cars and other such luxuries. But this is where algae bioreactors become especially interesting. They can produce the needed biomass constantly unlike current crops used for biofuel like corn which grows during a limited time of year. They need less space when compared to corn, and much of the corn plant is not even used in the biofuel. This leads to a large amount of unnecessary waste for a very small gain. Algae bioreactors may be a part of the answer to solve the conflict within the biofuel industry, but until then the bioreactor systems still need to be improved.
While algae bioreactors show a lot of promise, they still have some issues that need to be addressed. First, contamination is a serious problem that lowers the efficiency of the bioreactor system. In energy production it is important that the unit operate at, or at least near maximum efficiency to produce the most useable energy. A second issue is that quite a bit of space may be required, and in cities where buildings cast shadows these large bioreactors will need to be placed high were they can access sunlight. Location is very important, and a great deal of thought must go into installation, especially in cities where it becomes a massive undertaking to install the system. But even though algae bioreactors may have a ways to go, the outlook is good. A lot has changed in the last century, and it was not long ago that people like you and I were heating their homes with nothing more than a central fireplace that filled the home with a smoky air. Who knows what the next few years will bring?

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The Buzz about Honey Bee Decline

To many, bees are deemed a pesky nuisance to be avoided at all costs. They buzz and they sting, which is often met by swatting hands and ducking for cover. Yet, bees are vitally important to many flowering plants for their work as pollinators. Honey bees are an important pollinator of food crops across the world and their value to agriculture is estimated to be worth $14 billion in the United States alone. So, despite the reaction of many of us to say “Ew! Gross! Bugs! No!”, we depend on bees to pollinate the food we eat.

Perhaps, you’re now thinking “I guess bees aren’t so bad, maybe we can come to some sort of mutual understanding”. However, your new found friendship faces a roadblock because our insect friends are vanishing at an alarming rate. In 2006 and 2007, U.S. beekeepers started to notice a startling number of colony losses. What was peculiar about these losses was the absence of adult bees. The hives were usually empty aside from a few immature bees and the queen. Subsequently, this unusual phenomenon was termed colony collapse disorder (CCD).

So what’s causing the disappearances seen in colony collapse disorder? The answer is not so clear. Honey bees are hosts for a variety of pathogens, from viruses to bacteria, to mites and parasites. However, none of these factors alone are enough to explain the widespread losses seen in CCD. Recent research is implicating, instead, a group of pesticides called neonicotinoids that could explain the recent decline. Neonicotinoids are the newest family of insecticides introduced to the market. Therefore it was only within the last decade that scientists began to question whether these chemicals had something to do with honey bee decline and CCD.

Neonicotinoids have been considered a safer alternative to other pesticides because they selectively target the invertebrate central nervous system. They can be applied to crops without posing serious risk to ourselves and other mammals. However, their selectivity among insects is limited because beneficial pollinators, like honey bees, are still susceptible to neonicotinoid toxicity. These chemicals irreversibly bind to insect nicotinic acetylcholine receptors and in high enough exposure lead to paralysis and death.

Honey bees are consistently exposed to neonicotinoids in the field, especially during the sowing season in which seeds are planted using seed drilling machines. Seeds are often coated with neonicotinoids in order to provide pest protection for each plant from the moment it is put into the ground as a seed. However, the process of seed drilling has an unexpected consequence as a route to neonicotinoid exposure for bees. In the machine, the seed coating fragments and turns into a fine dust that is forced out into the surrounding area. Honey bees are subsequently forced to fly through the chemical plume during their foraging from hive to plant.

Another route of neonicotinoid exposure is caused by the systemic characteristics of neonicotinoids. Systemic insecticides are absorbed into all of the plant’s tissues and therefore confer insect protection to the entirety of the plant. This, however, is problematic for our tiny friends. When a honey bee goes to collect pollen or nectar from a treated plant, it is either ingesting the chemical directly or bringing it back to the hive to expose the rest of the colony. Neonicotinoids have been found in non-target areas surrounding agricultural fields.  The chemicals were found in the soil (despite no treatment for two seasons), in collected pollen, and in all dead and dying bees.

It is clear that bees have ample opportunity to come into contact with neonicotinoids, but what happens to them when they do? To answer this question researchers expose their tiny test subjects to various dosages of neonicotinoids and observe the effects. In one experiment bees were exposed to the neonicotinoid clothianidin at a field concentration that was determined as the highest concentration recommended for crop treatment. All of the bees died within three hours. Likewise the other neonicotinoid used, thiamethoxam, killed all bees in six hours, even at 200 times less than the field concentration.

RFID tracking device attached to honey bee

In some cases, however, hazardous effects of neonicotinoids on honey bees are not so blatant as to cause quick death. Neonicotinoids induce abnormal foraging behavior in bees. This means that exposure to these chemicals can disrupt the normal ability of bees to travel far from the hive and find their way back. In one study bees that ingested imidacloprid took a significantly longer time to return to their hive from a feeding site. The travel time of unexposed bees is fairly consistent, but with each increased dosage of imidacloprid the bees took longer to return to the hive. Some bees were never seen again.

It was unclear what actually happened to these bees, however, because the tracking was based solely on first person observation. However, one group of researchers took foraging observation one step further by using radio frequency tracking devices. The devices were attached to the bees as well as in the entrance of their hives. After being treated with sub-lethal doses of thiamethoxam, bees had a significantly reduced rate of being able to return to the hive. These findings seem to offer some insight to the absence of adult bees found in colony collapse disorder. There are no bodies because the bees never make it back to the hive from the field.

Although the future health of our tiny friends may be unclear, the research on the harmful effects of neonicotinoids has not gone unnoticed. In 2013 the European Commission of the European Food Safety Authority implemented a ban on the most widely used and harmful neonicotinoids including: imidacloprid, thiamethoxam, and clothianidin. Only time and future research wilI reveal the full extent to which neonicotinoids are impacting honey bee health. However, it remains apparent that the staggering decline of honey bees due to colony collapse disorder is in some way linked to neonicotinoid exposure.

How is Labor Divided in Honeybees?

With spring comes the start of warmer temperatures, and early blossoms. However, spring also brings out the species that hibernate for the winter. One of these species includes the honeybee. The honeybee is one of most fascinating organisms because of the unique behaviors it displays. Honeybees have the ability to create honey with only two ingredients, pollen and nectar. Their ability to make honey though is not the only thing that makes them interesting to study. Honeybees have developed an organized system of dividing labor amongst each other in their societies. Unlike humans, honeybees do not need a degree or give an interview for jobs. This division of labor in honeybee colonies is affected by several factors such as hormones, brain structure, and worker nutrition.

How is labor divided in the colonies?

The division of labor in honeybees is a complicated system. That is why it is important to understand the different jobs that exist in colonies. The division of labor is based on colony development and growth. In humans, we have assigned leaders that help organize the division of labor. However, here is no authority figure that regulates the distribution of jobs in honeybee colonies. Instead, honeybees go through various job stages throughout their lifetime. At a young age honeybees start off as nest workers, and do not travel outside the nest at all. Most honeybees also start off as nurses, and attend to the brood, or offspring, of the colony. At later stages in their life, honeybees become foragers and are responsible for food gathering. They may also continue on to become defenders of the colonies as well.

The Life Cycle of the Honeybee

What are the factors that affect the division of labor? 

All these different jobs that the honeybees perform are affected by several factors. One of these factors is juvenile hormone, which is responsible for behavioral development, metamorphosis regulation, and reproduction. The amount of this hormone has an important role in determining how the labor is divided. When JH-III, a type of juvenile hormone, is injected into honeybee, there were several changes that the honeybee went through. As the honeybee aged, several physiological changes were observed in the bee, especially in foraging honeybees. Compared to other honeybees of the same age, the honeybees with the JH-III injection became foragers earlier. These changes may be due to the increase in the amount of juvenile hormone, especially because the field bees tend to have larger amounts of juvenile hormone.

Juvenile hormone is not the only hormone that effects division of labor in honeybees. The hormone insulin is a regulator of glucose in the blood, and is produced by the pancreas. Insulin is an important hormone that is associated with which jobs honeybees perform in the colonies. When insulin is injected into honeybees, the honeybees transformed from nurses to foragers in less than two days. This is much faster then the usual time it takes for honeybees to make this job transition. It is clear that insulin levels can cause shifts in the division of labor. An increase in the amount of insulin produces more foragers then what would be expected.

A second factor that has an effect on the types of jobs that honeybees take on is brain structure. The brains of the honeybees contain a variety of biogenic amines that can have an effect on the division of labor. Biogenic amines are small molecules that contain one or more amine groups. These biogenic amines include dopamine, octopamine, and serotonin, which are found in the brains of honeybees. There is a direct link between the change in the level of these biogenic and the jobs honeybees perform. When the honeybees are young, only two to three weeks, they are more likely to process food, and care for brood. Once in adulthood, the honeybee has higher levels of the biogenic amines and spends most of its time foraging. In these ways biogenic amines are considered an important factor that contributes to how labor is divided in honeybee colonies.

Another factor that effects the division of labor in honeybee colonies is worker nutrition. Most of the energy in honeybees is stored in abdominal lipid, or fat. Foragers tend to have lower lipid levels compared to nursing bees. Foragers also have lower lipid levels on the first day of foraging compared to other days. The foraging was initiated by a decline in lipid storage. Also, because nurses need to take care of the nest and young, they also need more energy. This helps to explain why nurses tend to have higher lipid levels then foragers. Nutrition is an important factor for dividing labor in colonies.

Why study this complicated system at all?

The division of labor in honeybee colonies is affected by all of these factors, which includes hormones, brain structure, and worker nutrition. Division of labor is important in organisms, such as the honeybee, because it provides a system of order to rather complicated behaviors. Honeybees are model organisms that allow us to extend the study of the division of labor to other organisms like humans. We can compare how the factors that influence honeybee division of labor, might affect the types of jobs we perform. The division of labor is used to divide jobs in a variety of ways in humans. It can be observed in families, politics, and religion, as well as many other places. Without the division of labor, it would be hard to imagine what our societies would look like. Could you imagine what our country would look like without organized government? It may be fun at first, but sooner or later there would be too much chaos. Therefore, it is important that we understand the importance of the division of labor, and how it brings structure and order to a complicated group of organisms.