Colin B. Henderson

Iridovirus and Microsporidian Linked to Honey Bee Colony Decline

Background In 2010 Colony Collapse Disorder (CCD), again devastated honey bee colonies in the USA, indicating that the problem is neither diminishing nor has it been resolved. Many CCD investigations, using sensitive genome-based methods, have found small RNA bee viruses and the microsporidia, Nosema apis and N. ceranae in healthy and collapsing colonies alike with no single pathogen firmly linked to honey bee losses. Methodology/Principal Findings We used Mass spectrometry-based proteomics (MSP) to identify and quantify thousands of proteins from healthy and collapsing bee colonies. MSP revealed two unreported RNA viruses in North American honey bees, Varroa destructor-1 virus and Kakugo virus, and identified an invertebrate iridescent virus (IIV) (Iridoviridae) associated with CCD colonies. Prevalence of IIV significantly discriminated among strong, failing, and collapsed colonies. In addition, bees in failing colonies contained not only IIV, but also Nosema. Co-occurrence of these microbes consistently marked CCD in (1) bees from commercial apiaries sampled across the U.S. in 2006–2007, (2) bees sequentially sampled as the disorder progressed in an observation hive colony in 2008, and (3) bees from a recurrence of CCD in Florida in 2009. The pathogen pairing was not observed in samples from colonies with no history of CCD, namely bees from Australia and a large, non-migratory beekeeping business in Montana. Laboratory cage trials with a strain of IIV type 6 and Nosema ceranae confirmed that co-infection with these two pathogens was more lethal to bees than either pathogen alone. Conclusions/Significance These findings implicate co-infection by IIV and Nosema with honey bee colony decline, giving credence to older research pointing to IIV, interacting with Nosema and mites, as probable cause of bee losses in the USA, Europe, and Asia. We next need to characterize the IIV and Nosema that we detected and develop management practices to reduce honey bee losses.

Polarization lidar measurements of honey bees in flight for locating land mines.

A scanning polarized lidar was used to detect flying honey bees trained to locate buried land mines through odor detection. A lidar map of bee density shows good correlation with maps of chemical plume strength and bee density determined by visual and video counts. The co-polarized lidar backscatter signal was found to be more effective than the crosspolarized signal for detecting honey bees in flight. Laboratory measurements show that the depolarization ratio of scattered light is near zero for bee wings and up to 30% for bee bodies.

Field demonstration of a scanning lidar and detection algorithm for spatially mapping honeybees for biological detection of land mines

A biological detection scheme based on the natural foraging behavior of conditioned honeybees for detecting chemical vapor plumes associated with unexploded ordnance devices utilizes a scanning lidar instrument to provide spatial mapping of honeybee densities. The scanning light detection and ranging (lidar) instrument uses a frequency doubled Nd:YAG microchip laser to send out a series of pulses at a pulse repetition rate of 6.853 kHz. The scattered light is monitored to produce a discrete time series for each range. This discrete time series is then processed using an efficient algorithm that is able to isolate and identify the return signal from a honeybee in a cluttered environment, producing spatially mapped honeybee densities. Two field experiments were performed with the scanning lidar instrument that demonstrate good correlation between the honeybee density maps and the target locations.

Training and deployment of honeybees to detect explosives and other agents of harm

Sandia National Laboratories (SNL) has been collaborating with the University of Montanas (UM) engineered honeybee colony research under DARPAs Controlled Biological and Biomimetric Systems (CBBS) program. Prior work has shown that the monitoring of contaminants that are returned to a hive by honeybees (Apis mellifera) provides a rapid, inexpensive method to assess chemical distributions and environmental impacts. Members from a single colony make many tens of thousands of foraging trips per day over areas as large as 2 km2. During these foraging trips, the insects are in direct contact with most environmental media (air, water, plants, and soil) and, in the process, encounter contaminants in gaseous, liquid and particulate form. These contaminants are carried back to the hive where analysis can be conveniently conducted. Three decades of work by UM and other investigators has demonstrated that honeybees can effectively and rapidly screen large areas for the presence of a wide array of chemical contaminants and for the effects of exposures to these chemicals. Recently, UM has been exploring how bee-based environmental measurements can be used to quantify risks to humans or ecosystems. The current DARPA program extends this work to the training of honeybees to actively search for contaminants such as the explosive residue being released by buried landmines. UM developed the methods to train bees to detect explosives and chemical agent surrogates. Sandia provided the explosives expertise, test facilities, electronics support, and state-of-the-art analytical instrumentation. We will present an overview of the training procedures, test parameters employed, and a summary of the results of field trials that were performed in Montana and at DARPA field trials in San Antonio, TX. Data showing the detection limits of the insects will be included.

Long-wave infrared imaging for non-invasive beehive population assessment

Long-wave infrared imaging is used for non-invasive assessment of the internal population of honey bee colonies. The radiometrically calibrated camera signal is related to the number of frames that are populated by bees inside each hive. This enables rapid measurement of population without opening the hive, which disturbs the bees and can endanger the queen. The best results are obtained just before sunrise, when there is maximum thermal contrast between the hive and the background. This technique can be important for bee hive monitoring or for applications requiring frequent hive assessment, such as the use of bees for detecting chemicals or explosives.

Bees as Biosensors: Chemosensory Ability, Honey Bee Monitoring Systems, and Emergent Sensor Technologies Derived from the Pollinator Syndrome

This review focuses on critical milestones in the development path for the use of bees, mainly honey bees and bumble bees, as sentinels and biosensors. These keystone species comprise the most abundant pollinators of agro-ecosystems. Pollinating 70%–80% of flowering terrestrial plants, bees and other insects propel the reproduction and survival of plants and themselves, as well as improve the quantity and quality of seeds, nuts, and fruits that feed birds, wildlife, and us. Flowers provide insects with energy, nutrients, and shelter, while pollinators are essential to global ecosystem productivity and stability. A rich and diverse milieu of chemical signals establishes and maintains this intimate partnership. Observations of bee odor search behavior extend back to Aristotle. In the past two decades great strides have been made in methods and instrumentation for the study and exploitation of bee search behavior and for examining intra-organismal chemical communication signals. In particular, bees can be trained to search for and localize sources for a variety of chemicals, which when coupled with emerging tracking and mapping technologies create novel potential for research, as well as bee and crop management.

Polarization lidar measurements of honeybees for locating buried landmines

A polarization-sensitive lidar was used to detect honeybees trained to locate buried landmines by smell. Lidar measurements of bee location agree reasonably well with maps of chemical plume strength and bee density determined by visual and video counts, indicating that the bees are preferentially located near the explosives and that the lidar identifies the locations of higher bee concentration. The co-polarized lidar backscatter signal is more effective than the cross-polarized signal for bee detection. Laboratory measurements show that the depolarization ratio of scattered light is near zero for bee wings and up to approximately thirty percent for bee bodies.