## 3 Technological Advancements in Bee-Based Biosensors/Biomonitors
### Electronic Hives, Bee Counters, Chemical Monitoring at the Hive  
With honey bees and other social insects, the nest presents added opportunities for bio-sensing. For bees, the hive is the place from which foragers stage numerous forays during the day and to which the entire forager force returns at dusk. From 1973 through the early 1990s [36, 37, 48, 49, 75, 76, 77, 78, 79, 80, 81, 82], we capitalized on bees sampling surrounding environments, trapping at the hive, and analyzing samples of pollen, nectar and honey, wax, and even the bees themselves. We later found that bees' electrostatic charge improves their effectiveness as samplers and modeled particle size attraction as a function of charge for both chemical and biological (microbes/viruses) agents [83, 84]. In 1995, the US Army's Center for Environmental Health Research (USACEHR) contracted with us to explore using colonies of bees as rapid response \"miners\" canaries to both screen military waste sites for toxic chemicals and to provide surveillance of releases of any chemical toxic to bees this is likely to be toxic to people. We put the first electronic surveillance beehives on-line in 1995 [48, 49]. Fifty SmartHives(r) were used to monitor for releases of toxic chemicals at military toxic waste sites at Aberdeen Proving Ground (APG), just north of the city of Baltimore. Each hive was set up to permit environmental sampling for volatile (VOCs) and semi-volatile (SVOCs) chemicals. This was done using a combination of commercially available air sampling pumps, carbon molecular sieve tubes, and thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) to screen beehive atmospheres for VOCs and SVOCs [37]. We expected to see combinations of chemicals released by the bees themselves, their forage resources, and hive walls. We did not anticipate the full spectrum of more than 200 VOCs and SVOCs chemicals that we discovered [37], and noted that \"What most bee researchers have previously missed is the significant and often dominant presence of airborne contaminants from non-bee sources.\" For example, high perchloroethylene (PCE) levels in hives at APG were associated with queen loss from 50% of the colonies' place near a hazardous landfill. In 2005, we received the first US patent for an electronic hive [49] fitted with a variety of sensors. We were not the first to place nor to patent electronics on a beehive. Those milestones were achieved by [PERSON] and his associates, who published a design for a bi-directional bee counter, laying the groundwork for Lowland Electronics in Belgium and their line of Beescan, Apiscan and Bumblescan bi-directional bee counters. These counters were made commercially available in the mid-1990s [46]. The pioneering use of the Lowland Electronics counters was for studies of pesticide effects on bee colonies [46]. The Lowland Electronics design counts bees as they pass through portals fitted with infrared emitters and detectors. A bee is counted if it blocks an infra-red (IR) beam. We built communications capability missing from the Lowland Electronics counter into our SmartHives(r). We designed our own bi-directional, infrared bee counters and added to that our custom signal processing hardware and software which reduces the number of false positive data points resulting from bees starting to enter a counter portal, then backing out. These hand-built bee-counting units tend to be expensive and not well-suited to everyday colony management, although the cost has been warranted for some critical research and monitoring projects. We have experimented with alternative technologies for IR-based counters including: capacitance-based counters, visual and infrared image subtraction, still and video imagery (DARPA initiated projects, all documented in our Annual Technical Reports, 1999-2002 [82]). We found IR-based counter systems to be more robust and accurate than capacitance and video-based systems, but IR counters require regularcleaning and maintenance.