A few days back someone on a bike asked me the directions to the ‘lab’! Having worked in labs for years, I obviously couldn’t answer him because at a research institution, every nook and corner usually has at least one lab and his question was grossly insufficient for him to get anywhere close to his destination. If in your office complex, someone asked you the directions for ‘a cabin’, where would you point him to? It struck me then that to the world beyond, the lab is a mystery box and many people do not know what goes on within the confines of a research institution. So I decided to write this post to talk about what scientists really do….
As a researcher I observe a lot of cellular phenomena. Looking into the microscope is a routine affair. But macroscopic things around us are as interesting as things going on with microscopic entities. From flying patterns of birds to hierarchy in the ant world, everything throws light on some phenomenon that could potentially explain microscopic events. Observing such patterns in nature has been one of my interests.
‘Hypothesis building’ as many call it, is an important aspect of science and learning that is the first step to learning anything scientific. For any phenomenon to be tested, scientists come up with something called a ‘null hypothesis’. Simply put, it is the common notion as to why something happens. The scientist may have a different view for the same and his view is usually called ‘alternate hypothesis’. The null hypothesis (often designated as Ho) is what the scientist then tries to disprove or nullify through carefully designed experiments that answer either or both of the following questions.
A. Is the null hypothesis true or false?
B. If the null hypothesis is false, is the alternate hypothesis true or false?
A scientist used to guide me through the process of hypothesis building. We would pick a problem that interested us and generate hypotheses. We would then brainstorm over the feasibility of each of these hypotheses being true. I am using one of our problems here to give you a glimpse of science…
Problem:
“Why do mosquitoes hover over our heads at dusk?”
The hypotheses that I came up with (could be the stupidest thing you have heard, but it could still count as a hypothesis):
- Maybe the CO2 in our breath is a strong attractant at night
- They could be looking for a dark place to rest
- The moisture in our breath could attract them for egg-laying
- Maybe its an evolutionarily conserved trait and has no real reason
- Maybe there is a static attraction between our hair and their legs!
Let’s see if any of these is actually feasible!
- There are reports to show that CO2 is an actual attractant for mosquitoes. However, it doesn’t answer why the hovering happens at dusk. Unless…the CO2 levels in our breath goes up around dusk. The question then becomes, is there a reason to the increase in CO2 in our breath at dusk? Similar logic can be extrapolated to the moisture in our breath. We could measure the moisture and CO2 levels in our breath during the day and confirm its increase at dusk to see where the results lead us.
- A dark place to rest? Can they really detect that kind of differences in intensity of light? Why do they need a dark place to rest? Does the colour ‘black’ attract them at all? If we do a small experiment to see how many times they sit on black coloured ‘something’ over any other-coloured ‘something’, we may be able to answer this in a circuitous manner.
- Evolutionarily conserved trait for no reason? Highly unlikely. If it is a train that has to do with evolution, how many other insect species do we know with similar behaviour? At least I don’t know any!
- Static attraction? If there is a possibility of that happening, we could test the statics near out hair through the day and check if it increases or decreases and then see if we can extrapolate it to reproduce results with mosquitoes!
There you go…we built hypotheses and also designed some simple experiments to test them. Now that we have a few experiments on hand, we could perform them and if they show promise, continue the thread to see where it leads. If none of these experiments show any promise, start from scratch and build new hypotheses. Research, as you can probably appreciate now, is an iterative process…And all that goes into it is ‘brains’!
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aishwaryasivakumar 
Hi Aishwarya, first of all I am not 100% sure about this but I have a theory (another hypothesis) about this. Dusk is the time when most of the nocturnal mosquito species start their “day”. mosquitoes are known to follow co2 plume as a potential cue for their human host. Male mosquitoes however have evolved to follow Co2 plume as they know that it will eventually lead them to females (as they already are in the human vicinity). So once they arrive near the CO2 source/ human, they recognise a female by her wing beat frequency. Most mosquito species form a big mating ball in air. We could also say that hovering over human head is just an additional factor for their mating ball formation. Most females do not bite for a short period after the initiation of their activity. And hence the hovering and ball formation takes place even in our absence. This is regulated by their circadian activity and humans might be just an additional factor.
Such behaviour is reported for tse tse flies as well. Tse tse flies prefer to hunt in the day but try to avoid afternoon hunting. So initially it was thought that, their flight activation in the morning and evening is regulated by the presence of host odors/heat etc. However, later it was observed in olfactometer studies that their activity is highly regulated by their internal circadian cycles and not by any external factors. So a fly will leave her resting place and start flying even in an absence of any host signifying trigger. so the mosquito hovering could be a similar internal thing. Still its a thought and as u said it needs to be verified.
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Hi venkatesh, thanks for your comment… Your hypothesis does seem valid. However the mating ball being over the head has to be additionally facilitated by a cue from humans and therefore I think it’s co2. If it happens even in the absence of humans then you might be right about humans just being a coincidence. I really enjoyed reading about tse flies. I had not known about that. Thanks a lot…. Follow this space to read more comments. I would also be happy if you could file the blog!
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