The chemicals emitted by bed bugs (both dead and alive) could be the key to their accurate detection and trapping.
The resurgence of bed bugs as a public health concern has been brought to global attention in recent months. Those in the pest control industry know that new and sustainable methods to monitor and control bed bugs are greatly needed. One of the greatest challenges is detection; due to their nocturnal activity, small size and discreet behaviour, bed bugs are difficult to find in the first place.
The resurgence of bed bug infestations and the inefficiency of chemical insecticides in many parts of the world has led to a renewed interest in volatile organic compounds (VOCs) as a method of bed bug detection. VOCs are chemicals released by bed bugs during various behaviours; if these VOCs can be detected and measured, it will alert pest managers to the presence of bed bugs without the need for intrusive inspections. But how much do we know about VOCs and can they really be used as a detection tool? To answer this, a team of researchers assessed the potential for using VOCs by analysing the scientific literature published in the last two decades.
Currently, the presence of bed bugs is determined mainly by visual inspection or using specially trained sniffer dogs. These methods are time-consuming, requiring the expertise of trained professionals, which can be costly. Volatile organic compounds are considered a promising approach for bed bug detection.
So what exactly are VOCs? They are chemicals released by bed bugs as a way of communicating with each other. These chemicals are released during various behaviours such as defence, mating or aggregation and the concentration of the chemical varies depending on the sex and life stage of the bed bug. VOCs are not only emitted by adults but also by immature bed bugs in the developmental stages. Interestingly, VOCs are also emitted from exuviae or dead specimens.
As pest managers will know, bed bugs have a very characteristic smell. A review of the scientific literature showed that 49 VOCs (semiochemicals) have been detected in bed bugs – 23 in the common bed bug Cimex lectularius and 26 in the tropical bed bug Cimex hemipterus. These semiochemicals are released as a gas, meaning they can be detected by specially designed monitors.
VOC detection is commonly performed by active or passive sampling of the air using absorbing tubes, the contents of which are then analysed in the laboratory by gas chromatography-based analytical platforms. It is therefore logical that the next advancement in bed bug detection will see pest managers using a handheld portable device to sample the air in a potentially infested room. The gas chromatography analysis will allow for the on-site detection of bed bugs in infested locations, not only confirming that bed bugs are present but that they have been present at some point in recent times (as VOCs are also emitted by dead bed bugs and exuviae).
From the pest manager’s point of view, this kind of air sampling is an attractive prospect. VOC detection tools can be used to quickly diagnose sites of possible infestation and control strategies can be implemented quickly without the need for customers to move out of the property or for furniture to be moved – both of which are currently barriers to successful detection.
These same VOCs also have potential for use in bed bug trapping and monitoring devices. The sex and aggregation pheromones are of particular interest. Adhesive or pitfall traps that are impregnated with these attractive VOCs can be used as monitors. Active monitors can also be heated to draw the bed bugs in and therefore increase the likelihood of successful detection. The combination of a sugar-yeast monitor with a chemical lure is also an affordable and effective tool for monitoring bed bugs. This monitor is especially useful for monitoring bed bugs where a human host is not present.
As part of a wider bed bug control strategy, traps containing large amounts of sexual or aggregation VOCs can be placed in the field to confuse bed bug males and females, making it difficult for them to find each other to mate.
Currently, few tools exist for detecting a low number of bed bugs. Yet early detection is vitally important in bed bug control; catching an infestation early reduces the costs associated with bed bug management and the spread from infested dwellings to new locations. The use of VOCs in traps and detection devices has the potential to deliver significant improvements to bed bug management, increasing efficiency, saving costs and reducing insecticide use.
Further reading: Akhoundi, Mohammad & Chebbah, Dahlia & Elissa, Nohal & Brun, Sophie & Jan, Julie & Lacaze, Isabelle & Izri, Arezki. (2023). Volatile Organic Compounds: A Promising Tool for Bed Bug Detection. International Journal of Environmental Research and Public Health. 20. 5214. 10.3390/ijerph20065214.