Symptoms of CCD in collapsed colonies (Bee Alert Technology, 2007).

• The complete absence of adult bees in colonies, with no or little build up of dead bees in the colonies or in front of those colonies.

• The presence of capped brood in colonies.

• The presence of food stores, both honey and bee bread,

I.  which is not immediately robbed by other bees. 

II.  attacks from hive pests such as the wax moth and small hive beetle are noticeably delayed. 

Symptoms of CCD in colonies actively collapsing (Bee Alert Technology, 2007).

• An insufficient workforce to maintain the brood that is present.

• The workforce seems to be made up of young adult bees.

• The queen is present.

• The cluster is reluctant to consume provided feed, such as sugar syrup and protein supplement.

Figure 1. Varroa jacobsoni Mite

(Bauer, 2002).

Varroa Mites

Varroa jacobsoni, were first found in Florida in the mid 1980’s.  The mites suck the blood of adult bees and brood, shortening the lifespan of the bee.  Reproduction takes place in the hive on the developing bee brood.  To do this, the female mite enters the brood cell right before capping to become sealed in with the larvae.  Honey bees can emerge with deformed legs or wings.  The mite eggs are laid in the cell and feed off the maturing larvae until they emerge out of the cell with the bee.  The mites are spread through drifting workers or when colonies rob an infected colony.  Varroa mites are often confused with the small hive beetle, but the varroa mites are slightly smaller, have eight legs instead of six, and are less circular.  Insecticides can be used to treat the hives that have varroa mite infestations (Bessin, 2007).  Hygienic behavior has been shown to arise spontaneously and the bees clean the mites off themselves, without the use of chemicals, but it takes time for such behaviors to evolve (Watanabe, 1994)

Figure 2. Micrograph showing a bee trachea infected with mites

(De Guzman, 2006).

Tracheal Mites

Acarapis woodi lives within the trachea or breathing tubes of adult bees.  The mites pierce the breathing tube walls and feed on the blood of the bee.  Severe infections can cause the bee to lose the use of their flight muscles located in the thorax.  They are very small in size and spend their entire lifecycle, except for migration periods, in the respiratory system.  The mites spread through bee to bee contact when the female mite climbs out of the bee and onto a younger, more susceptible bee.  Dissection of the trachea is the only way to diagnose the tracheal mite (Figure 2).  In severe infections, the trachea is completely black and filled with mites of different stages.  Colony populations can dwindle the most in late winter and early spring when mite levels are highest.  One treatment for mites is placing menthol pellets in the hive for four to six weeks (MAAREC, 2003).  As temperatures rise and air exposure increases, the menthol vaporizes and its fumes fill the colony. As the bees breathe the vapors, the mites are killed (Bessin, 2004).

Figure 3. Nosema staining on the outside of the hive

(MAAREC, 2003).

Nosema

Nosema apis is a spore forming protozoan that infects the digestive tract of adult bees.  The spores are ingested by the with food or water and the spores germinate and multiply in the lining of the bee’s midgut.  It inhibits the bee’s ability to digest food and causes brood-food production to decrease, lowering colony development.  Increased winter losses can also result from decreased honey production.  Infected bees show symptoms of dysentery, and worker bees that are infected may defecate in the hive or on the outside (Figure 3), rather than away from the hive.  Infected Queens have reduced egg production and a reduced life span.  Dissection and examination of the bee’s digestive tract is the only way to identify if the hive is plagued with the protozoan.  Chemical treatment can be done with Fumidil-B (Fumagillin); however the chemical will only suppress the vegetative stage and not the spores of the protozoan.  Infection could still continue after the medication has been consumed. The best defense for wintering colonies is to ensure that there is plenty of honey for the winter (MAAREC, 2003).         

  Figure 4. Webbing Produced by Wax Moth Larvae (Goodman, 2006).

The Wax Moth

Galleria melonella, is a moth that affects beeswax combs left unattended or combs in weak or dead colonies.  The moth only becomes a threat when the temperature is over 40 degrees Fahrenheit.  The adult female moths deposit masses of eggs onto the unprotected combs at night.  The eggs hatch into caterpillars and the feeding on cocoons, cast skins, and pollen chews through and destroys the beeswax cells.   Destruction also occurs when silken galleries are spun to protect them from bees attempting to clean out the colony.  Beeswax combs are often reduced to a mass of webs and debris (Figure 4).  The wax moth larvae spins a silken cocoon attached to the frame and over-winters in the pupae stage.  The wax moth can be easily avoided with a strong, healthy colony and by keeping stored equipment at a cool temperature during warm weather (MAAREC, 2003).

Figure 5. Adult Small Hive Beetles on a Healthy Honey Bee Hive

(Anderson, 2002)

The Small Hive Beetle

Aethina tumida originated in Africa and was discovered in Florida in 1998.  It is unknown how it arrived in North America, but it has spread to other states (Fell, 1999).  The female beetle lays eggs on or near a beeswax comb of an unprotected or weak colony.  The larvae consume pollen, combs, and larval honey bees.  The small hive beetle is only found in bee colonies where there is sandy soil because the larvae require sandy soil to pupate successfully.  Once an adult, the beetle will feed on honey bee eggs.  The beetle will also defecate in the honey, and somehow alter it to ferment and run out of the combs (MAAREC, 2003).  The honey of an infected hive will smell like decaying oranges.  There is an approved chemical from the Bayer Corp. effective in killing adult small hive beetles.  The best prevention is to keep the hive healthy and strong (Fell, 1999).  One of the signs of CCD is the delay in hive intrusion from the small hive beetle and wax moth, which would otherwise be very quick to invade the empty hives (Stokstad, 2007).  

1868  

Recent loses occurred in the United States in the Spring of 2001, 2004, and 2007.  Of the estimated 2.4 million honey bee colonies in the nation, a recent survey conducted by the Apiary Inspectors of America estimated that between 651,000 and 875,000 colonies were lost over the winter of 2006-2007.  Taking into consideration the known threats to honey bees, over 25% of beekeepers were considered to have Colony Collapse Disorder and an unknown cause (Underwood, 2007).   

Transporting thousands of bee colonies is harmful to the health of the colonies.  Bees are transported in giant 18 wheelers and stacked on top of each other, which stresses the bees (Thomas, 2007).  Queen bees have their wings clipped to prevent swarming, when bees leave and start a new colony.  The queens are also killed and replaced frequently (Thomas, 2007).  Beekeepers with industrial size operations experience the same problems that industrial poultry farmers have; diseases spread quickly among the colonies (Thomas, 2007).  Also, by exposing the bees to thousands of other colonies from around the country during mass pollination, the chance of contacting other parasites, viruses, bacteria, and fungi increase (Thomas, 2007).  Additionally, the bees are provided an unnatural, supplemental diet during migratory periods.  The migratory bees are fed fructose sugar syrup, which is freighted in tankers around the country  (Thomas, 2007).  To observe the effects of trucking on the diets and health of bees, 140 colonies will be observed stationary for honey production while another 140 colonies are moved five times for crop pollination (Stokstad, 2007).

Figure 7.  Healthy bees on a

honeycomb (Ausmus 2007)

One specific class of pesticides, neonicotinoids, is especially harmful to honey bees.  Neonicotinoids are nicotine-based insecticides that disrupt the central nervous system of insects (Fishel, 2005).  Nicotine is an extremely toxic chemical that speeds up nerve impulses and large doses of nicotine allow too many nerve impulses to shoot through the synapses (Mussen, 2004).  Neonicotinoids react by blocking a specific neuron pathway that is more abundant in insects than warm-blooded animals, so neonicotinoid insecticides are not very harmful to mammals (Fishel, 2005).

Survey Representation:  Two-thirds of respondents operate fewer than 100 colonies (Figure 9).  The remaining third roughly evenly represent larger scale operations of more than 100, 1,000, and 10,000 colonies (Bee Alert Technology, 2007).   This graph shows that beekeepers do not blame mites for the bee deaths, nor do they blame pesticides.  Laboratory studies done on the effects of imidacloprid on the foraging abilities of bees concluded that the higher the dose of imidacloprid, the slower and more lethargic the bee became.  The bees were not allowed to return to the hive right after foraging and bees exposed to the higher dose had trouble getting out of the cage they were contained in and did not return to the hive or the place of foraging (Bortolotti et al, 2003).  So the bees could be disappearing because of pesticides, but may not be exhibiting the signs beekeepers look for in pesticide poisoning.    Similarly, some of the bees given smaller amounts of imidacloprid did not return to the feeder to forage (Bortolotti et al, 2003).  This type of behavior in the field could contribute to an unhealthy diet and the need for the bee to travel further from the hive for a respectable source of food.