Overview

Without the hard work of bees, the difficulty of planning dinner would increase significantly. Taking time out of our daily routine to consider all that bees have done for us would take quite a while. We would not have some of the grains, fabrics, fruits, and vegetables that we enjoy. Alfalfa, cotton, almonds, oranges, cherries, and livestock that feed on bee pollinated crops would all decline significantly, if not completely perish. We would not have the flowers and trees that make our world beautifully diverse. Bees pollinate 70 out of the top 100 food crops, which supply 90% of the world’s nutrition. It is apparent that bees are an integral part of the ecosystem and human life.

Unfortunately, bees have been in decline for about 30 years and the death rate has gone up in the past decade. This phenomenon is caused by a number of factors, including the use of neonicotinoid insecticides, climate change, and parasites. One of the most notable parasitic mites that infects bees is the Varroa destructor mite. This particular mite feeds off of the bee’s hemolymph, the blood-like substance, transmitting viruses like Deformed Wing Virus (DWV) in the process. DWV disrupts the bee’s development, causing them to have stubby wings and short bodies that prevent flight.

A few methods to deal with V. destructor are ineffective as they do not target the mite at a crucial phase when the bee is most susceptible. The larvae are sealed into combs with the mites, a place that some treatments simply can not reach.Other treatments rely on chemicals that increase bee mortality rate. For example, formic acid has a harmful effect on capped and uncapped honey bee brood1. In addition, resistance against various methods are developing in certain Varroa mite populations.

Currents techniques used to deal with V. destructor mites include using bio-pesticides, alcohol washes, synthetic chemical pesticides and the sugar shake method.

Our modus operandi: protect all the bees and larvae from the inside out. Using synthetic biology, we designed E.coli that produces the miticide oxalic acid in the midgut of any bee that ingests it. Our construct will include the Petal Death Protein (PDP). This protein aids in the conversion of oxaloacetate, a natural product of the Kreb’s cycle, into oxalic acid. Oxalic acid is an optimal weapon against the mites as the concentration needed to kill a mite is 70 times less lethal to the bee. The acid is already being used in syrup and spray solutions.

In order to apply this construct to the hives, we plan to use nurse bees to feed a mixture of E.coli and sucrose to the young bees. In the midgut the E.coli will produce low concentrations of oxalic acid that are lethal to only the mite, and that will diffuse into the hemolymph of the bee. This will cause the Varroa destructor to die if it sucks the bee’s hemolymph.

Our construct is more effective than current methods used, as it allows us to tackle the issue at an earlier stage, when the bee has not hatched from the uncapped brood. It also targets the mite more directly than other spray-on insecticides. With this project, we will take one step closer to combatting Colony Collapse Disorder (CCD), the devastating issue of decreasing global bee population, by improving the method of killing one of the main culprits of CCD: the Varroa destructor mite.