The BG-Sentinel: Biogents’ mosquito trap for researchers and control professionals

Different variations of the BG-Sentinel can be used according to the target species, the study aim and conditions in the field. The trap can be used with or without carbon dioxide, and with Biogents’ proprietary human scent imitation for a anthropophilic mosquitoes (such as Aedes aegypti or Culex quinquefasciatus), the BG-Lure.

If you aim to collect biting midges (Ceratopogonidae), please use the BG-Pro (the sucessor model of the BG-Sentinel), and operate it with UV light, CO₂, and the collection set for biting midges.

The BG-Sentinel needs a 12 V DC energy source. For a use on the electricity network, Biogents supplies mains adaptors. In the field, the traps can be hooked up to batteries. For normal field conditions, we suggest the use of motorcycle batteries which are readily available in most regions of the world. A capacity of 11 Ah is needed for every 24 hours (this includes a security factor).

All variations and available accessories can be found in the product catalog for researchers.

Monitoring attractants

When used in combination with the BG-Lure, Biogents’ proprietary artificial human scent, the BG-Sentinel is an excellent monitoring trap for yellow fever mosquitoes, their relatives from the genus Stegomyia, and other anthropophilic species. The BG-Lure releases an artificial skin odor (ammonia, lactic acid, and caproic acid) in a finely tuned ration similar to that of human skin. Due to its form and design, the BG-Sentinel also permits the researcher to use highly diverse attractants, including alive animals as lures or a number of other stimuli, thereby adjusting the capture spectrum precisely to specific needs of the study.

Surveillance projects

The BG-Sentinel is very sensitive for tiger mosquitoes, but it also collects several other invasive mosquito species. It is therefore ideal for surveillance programs.

Here are some examples for studies, in which invasive mosquitoes were detected with the help the BG-Sentinel traps.

• Aedes albopictus – first record on York Island, Australia (Ritchie et al. 2006) and first record in Gabon (Krüger & Hagen 2007)
• Anopheles albimanus – first record on St- Kitts in the Caribbean (Mohammed & Smith, 2011)
• Aedes albopictus, Aedes japonicus, and Cs. longiareoliata  in Germany (Werner et al., 2012)
• Mansonia flaveola – first record in Rondônia State, Brazil (Gama et al. 2012)
• Wyeomyia mitchellii – first record in French Polynesia (Marie & Bossin, 2013)
• Culex coronator – first record in in the state of Virgina, USA (Akaratovic & Kiser, 2017)
• Culex lactator in Florida, USA (Reeves et al. 2023)

Here is an example from Spain, where Roiz et al. (2012) compared the efficacy of different CO2-baited BG-Sentinel traps (alone, with the BG-Lure, and with octenol) to that of a CO2-baited CDC trap for potential West-Nile vectors in a Mediterranean wetland:

• All BG-Sentinels captured significatly more Anopheles atroparvus than the CDC trap.
• Additionally baited with the BG-Lure or with octenol, there was no significant difference to the CDC trap for Culex modestus, Cx. perexiguus, Cx. pipiens and Cx. theileri.
• The BG-Sentinels collected significantly more bloodfed An. atroparvus and Cx. modestus.
• With the addition of either the BG-Lure or octenol, the BG-Sentinel always performed, better for bloodfed Cx. perexiguus, Cx. pipiens and Cx. theileri than the CDC trap.
• ->”In conclusion, BGS traps with CO₂ are highly suitable for monitoring the Culex mosquito species that are vectors of WNV in Mediterranean wetlands and similar habitats”

How to perform mosquito surveillance?

• ECDC (European Centers for Disease Control): Guidelines for the surveillance of invasive mosquitoes in Europe (see page 15. Basic recommendation: twice per month monitoring with BG-Sentinel traps)
• CDC (Centers for Disease Control):

Comparing traps, attractants and other mosquito sampling methods using the Latin Square Design >

A controlled CO₂ emission for monitoring endemic and invasive mosquito species

When used in combination with carbon dioxide, the BG-Sentinel is an excellent monitoring trap for mosquitoes in general. The gas is released from an opening above the trap, thereby adding a smaller CO₂ plume to the upwardly directed scent plume in the trap. This mimics the natural spatial distribution of body scent and breath. The trap receives a controlled supply of carbon dioxide from a compressed gas cylinder: A special pressure reducer enables the adjustment of  the pressure and the flow rates to the local and seasonal conditions. We recommend a flow rate of 0.5 kilograms per day (red marker on the display of the pressure regulator).

In contrast to dry ice, gas cylinders can be stored until use with no trouble. This permits a flexible response to changes in the weather, and makes it possible to use the traps at an ideal time. The gas cylinders are the same that are used for draught beer and the production of carbonated drinks in pubs and restaurants.
To reduce your CO₂ costs the BG-CO₂ timer allows you to control when CO₂ is released by establishing specific start and stop times. It enables you to set up two start and end times to release CO₂ each day.

Dry ice can also be used if preferred. In this case, the gas can be liberated from an isolated container with dry ice 30 to 40 cm above the intake funnel of the trap.

Examples for studies in which the BG-Sentinel was used with CO₂.

• A Germany-wide mosquito monitoring project called “Geographical and seasonal distribution of endemic and invasive mosquitoes in Germany” deployed around 60 BG-Sentinels with CO₂ and BG-Lure at selected locations throughout Germany to determine the spectrum of the mosquito species. In 2011, the species captured in this project already included adults of the invasive species Aedes albopictus, Ae. japonicus and Culiseta longiareolata (Werner et al 2012).
• A study from Florida pointed out, that for certain mosquito species such as Cx. nigripalpus and Cx. coronator, and overall higher catch rates, the BG-Sentinel should be operated with CO₂ (Wilke et al. 2019).
• In Spain, Roiz et al (2012) concluded, that “BGS traps with CO₂ are highly suitable for monitoring the Culex mosquito species that are vectors of WNV in Mediterranean wetlands and similar habitats”

Mosquito trapping without carbon dioxide

Although carbon dioxide further enhances the efficacy of the BG-Sentinel, the trap is already an excellent trap for Stegomyia mosquitoes when baited with the BG-Lure alone:

• Rose et al. 2010: HLC vs BG-Sentinel with BG-Lure for catching Aedes albopictus. Two research projects in different Italian cities showed that BG-Sentinel traps collect similar numbers of Aedes albopictus females as human landing collections in 30 to 90 minutes. About half of the females captured had either had a recent bloodmeal, or they were gravid or parous.
• Azara et al. 2013: This study showed that CO₂ has primarily an enhancing effect on the efficacy of BG-Sentinel for capturing Culex spp in Manaus. For Ae. aegypti, catch rates increased only slightly, but the positivity rate of the trap was higher, when traps were operated with CO₂.
• Englbrecht et al. 2015: In this study, the BG-Sentinel was evaluated as a management tool to reduce Aedes albopictus nuisance in Cesena, North Italy. Three intervention sites were compared with three contol sites. It was shown that 87% fewer Ae. albopictus individuals were collected by human landing collections at the intervention sites, as compared to the untreated control sites. These results indicate that the sustained use and proper placement of efficient mosquito traps can significantly reduce Ae. albopictus biting pressure.

Other species that are captured well without the need for carbon dioxide include Culex quinquefasciatus (e.g. Maciel de Freitas et al. 2006) and Ae. mediovittatus (Little 2011). Schmied et al. (2008) used worn socks to capture Anopheles gambiae, and Scholte et al. (2012) captured the invasive mosquito Aedes atropalpus in The Netherlands without using CO2.

Positioning is an important factor for the catch rates. Test different locations!

• application outdoors
• placement in shady, wind-protected moist places, near breeding sites of mosquitoes

How to position a Biogents trap >

Scientific studies on our traps

A large and growing number of scientific studies shows that the BG-Sentinel (a.k.a.the BG trap or BGS trap) is a superior trap for mosquito surveillance and monitoring. The exceptional capture rates of this trap are documented in more than 300 scientific publications:

Online database with publications on studies using the BG-Sentinel >

More literature also on our webpage www.bg-sentinel.com >

List of studies with Biogents traps >

List of scientific publications of our researchers >

Overview over two studies (one in Cesena and one in Manaus) with Biogents traps as control tools >

More about our scientific foundation and publications >

Product catalog

Biogents product catalog for professionals: BG-Sentinel trap etc. >

Manual

Manual for the BG-Sentinel trap >

Other documents

Placement and effect of a Biogents mosquito trap >

The BG-Sentinel has quickly become a gold-standard method, at least for monitoring of Aedes aegypti and Aedes albopictus, and has been used in countless research and surveillance projects.

The successor model of the BG-Sentinel for the researcher market is the BG-Pro trap.

The BG-Pro can do everything the BG-Sentinel does, and has several other advantages (Degener et al., 2021):

1. In comparison to the BG-Sentinel, the BG-Pro yields, in most cases, equivalent, or superior catch rates of Ae. aegypti, Ae. albopictus, Ae. polynesiensis, or Culex spp.
2. The BG-Pro uses 35% less power than the CDC and 75% less than the BG-Sentinel, and can therefore run at 5 V for 2 days using a small lightweight 10,000-mAh rechargeable power bank.
   
3. The BG-Pro is a modular trap that can be used in at least three different configurations (by adding or removing certain accesories): BG-Sentinel style, CDC style, and EVS style.
4. When configured as CDC style and EVS style, and compared to CDC and EVS traps, the BG-Pro reached either equivalent or similar catch rates for Ae. vexans, Cx. pipiens, Cx. erraticus, and Cs. melanura.
5. The BG-Pro is made of higher quality parts, but is slightly cheaper, than the BG-Sentinel.

The BG-Pro has already been used in several studies with different objectives and excellent results:

• Brazil – Ellwanger et al. 2022: BG-Pro used in BG-Sentinel style and EVS style, both baited with CO₂ from dry ice and BG-Mozzibait.
  • Mosquitoes from at least 50 species and 14 genera were collected
  • Two first descriptions for the State Rio Grande do Sul: Mansonia pessoai and Toxorhynchites theobaldi

• Netherlands – Agliani et al. 2023: BG-Pro baited with CO₂ from molasses fermentation.
  • 96 Mosquito pools of Cx. torrentium/ Cx. pipiens were tested for USUV and Plasmodium infections. 18 pools were positive for Plasmodium spp

• Thailand – Chaiphongpachara et al. 2022: BG-Pro in CDC style (hanging, baited with CO₂ and BG-Lure).
  • Anopheles females belonging to eight species collected: An. baimaii, An. minimus s.s., An. epiroticus, An. jamesii, An. maculatus s.s., An. barbirostris , An. sawadwongporni, and An. aconitus.

• Thailand – Chaiphongpachara et al. 2022: BG-Pro in CDC style, baited with CO₂ and BG-Lure, and larval dipping for mosquito survey.
  • Mosquitoes from 65 species were collected with BG-Pro traps from several provinces (table S1)
• Thailand – Saiwichai et al. 2023: BG-Pro in CDC style, with CO2 and BG-Lure
  • Survey of Japanese Encephalitis vectors Cx. pseudovishnui, Cx. tritaeniorhynchus, and Cx. vishnui and posterior geometric morphometrics and DNA barcoding, as the three species have very similar morphology.

If you aim to collect biting midges (Ceratopogonidae): operate the BG-Pro with UV light, CO₂, and the collection set for biting midges.