BiteOscope: an open platform to study mosquito blood-feeding behavior

Author's response

Felix JH Hol shared

Open questions 

1. This is a very exciting tool, opening many possibilities. You included already, various elements affecting mosquito behaviour (eg heat and light). Can you add odours to the substrate, to complement the known attractants? Can you simultaneously use various substrates with different properties to determine mosquito behaviour upon provision of choices (decision-making)?

Those are all interesting suggestions! The short answer is yes/we’re working on it. There is lots of literature regarding which odourants attract mosquitoes to humans. Luckily, many of those odorants are commercially available and can be used to coat surfaces and/or be diffused into a cage. We are currently working on this.

Making a `choice assay’ is another interesting option. We have some preliminary results with this, and it is indeed possible to present and evaluate multiple bite substrates in the same cage. One caveat is that this requires a larger field of view and as a consequence it becomes harder to resolve tiny details in the images. Despite this, it’s an interesting opportunity for future research.

2. You work can easily be adapted to other vectors which are important sources of pathogen transmission like tsetse flies, sandflies, and triatomine bugs. The behavior of those vectors during the interaction with the skin is also incomplete. Are you planning to adapt the BiteOscope to study other vectors?

That would be an amazing thing to do. We have some colleagues that work with tsetse flies and sandflies and it would be wonderful to translate our tool to other vectors. It would be great if interested researchers would get in touch about adapting the biteOscope to their experimental systems.

3. Also related to decision-making, there have been studies showing differences in attraction to different animals. Can you adapt the skin mimic accordingly, to simulate skin of different animals and observe feeding preferences? This might shed light into transmission and non-human reservoirs of pathogens.

That would be a very interesting thing to do. I can imagine that odorants differ quite a bit between different host species, and also the texture of the skin — fur, feathers, etc. It would be interesting to combine our approach with fabrication methods that mimic different textures and see how that affects blood feeding.

4. Have you planned on using the skin mimic to study pathogen transmission “the other way around”? Namely, adding parasites to the substrate, and observing mosquito behavior upon uptake of pathogens?

Yes, that is something we’re very interested in. Likely, we would not add the pathogen to the substrate directly as we expect the effects of pathogen infection to become apparent a while later (when an infection has been established in the mosquito), yet we are very interested in using the biteOscope to compare the behavior of infected and non-infected mosquitoes. I hope our method will be useful to decipher the effects of pathogen infection on mosquito behavior.

5. You mention in your work that the richness of data you obtained from imaging multiple mosquitoes (i.e. exploiting the value of high-throughput) allows quantitative characterization of individual behaviours hidden in population averages. Can you expand further on this point, and why this might be relevant to our understanding of mosquito-mammal interactions and pathogen transmission?

There are many possible answers to this question, depending on what you’re interested in and what you decide to measure/analyze. In general, I believe that while population averages are very useful, they hide the underlying distribution. For instance, the population fraction that fully engorges is often the outcome of a blood feeding experiment, however, this does not provide information about how many bites individual mosquitoes needed to come to full engorgement. From modeling studies we know that the number of (potentially infectious) bites is a very relevant parameter to estimate the transmission of disease. We anticipate that our method will enable detailed measurements like this. 

6. Have you thought of integrating to your setup, another tool which allows imaging and study of the mosquito brain during behavioural experiments, and how signals might be integrated during visual and olfactory stimulation – which you provide with your skin mimic?

There are several labs that have the capability of imaging the mosquito brain while presenting different stimuli and I think this is a very important tool to better understand the sensory neurobiology of mosquitoes. Incorporating something like that in our current set up would be very challenging as brain imaging typically is performed on immobilized mosquitoes, whereas mosquitoes are allowed to move in our set up. However, who knows what the future will bring….