Backswimmer

I really enjoy field work.  Having grown up in an outdoorsy family, I spent a lot of time outside as a kid.  When it came time to choose a senior thesis topic in college, I headed straight for the local wetlands, plopped myself down on a boardwalk, and watched damselflies flying around for several weeks.  I swore to myself that I was going to do all of my graduate research outdoors because that’s what I loved to do.

My regular readers know that plan didn’t quite pan out (click here for examples).  But there’s a reason for that!   There are times when it’s easier do work in the lab and there are questions that are nigh impossible to answer in the field.  So, today I’d like to do something a little different for Science Sunday.  Instead of discussing an article about research, I’m going to discuss a few (very few) of the pros and cons of working in the field versus the lab.  For the scientists out there: you probably know all this already, so thanks for stopping by.  But for those of you who aren’t scientists, this might give you some insight into how scientists plan their experiments and the research decisions they make.

Let’s start with a hypothetical question, something that you might find me doing: do the behaviors of backswimmers (pictured above) allow them to use the air bubble they carry on the underside of their abdomens as physical gills so they can extract oxygen from the water?  Now, there are several different ways I can approach this question, so let’s consider some pros and cons of doing this sort of study in the field.

Field Work

PRO: You are able to observe the bugs in their natural surroundings.

When you’re dealing with behavioral questions, you can often make the best observations in the field.  In our hypothetical scenario, the bugs are going to be much happier, and therefore much more apt to behave as they do normally, if you observe them in the field.  As an observer, you will cause a certain level of distraction that might interfere with their normal behaviors to some extent, but it’s certainly going to be far less than what you’re going to get by scooping the bugs out, driving them back to the lab, and dumping them into containers.  When possible, it’s great to do behavioral studies in the field for this reason.  However, that’s not always possible because…

Con: You have no control over the conditions

To be able to say that X causes Y, you need to do a carefully controlled experiment where all the variables are accounted for.  It’s possible to do experiments in the field, but there are a lot more variables that you have to take into account.  For example, let’s say you’re doing a field experiment with the backswimmers.  However, it turns out that one set of treatments was applied to bugs in the middle of the stream and another to bugs closer to the shore.  If you compare the treatments and observe differences, you can’t ever be completely sure that you know why they’re different.  Your treatments likely had an effect, but what about the differences in flow between the two areas (faster in the middle, slower closer to shore)?  The increased energy demands of swimming in the middle of the stream relative to the areas closer to shore?  The different oxygen levels in the two areas?  Taking your experiment into the lab ensures that the only difference between the two treatments is the treatment itself so you can say that your treatment caused the observed outcome.  You probably also want some field observations when possible so that you provide evidence that your lab experiments didn’t affect the behaviors (e.g. did you know that female mantids don’t normally eat their mates and only do that in the lab?), but this isn’t always possible.

Lab Work

Working in the lab has benefits, but it’s not always the ideal place to work.  Apart from being able to precisely control your experiments at the cost of removing things from their natural environment, the pros and cons of lab work include:

Pro: Greater access to a wider variety of Research tools and equipment

There are some things that are difficult or impossible to do in the field.  For example, let’s say you want to measure the oxygen in the air bubble that the backswimmer carries with it in the water.  That involves using some expensive precision equipment with specific power and space requirements that are hard to replicate in the field.  You might want to use a microelectrode to measure the oxygen level of the bubble.  Microelectrodes break very easily, so dropping one into the stream or on the ground would be a terrible thing – $5000 down the drain!  You wouldn’t be able to use the stands or the micromanipulators in the field that make using the electrodes easy in the lab.  It’s certainly not ideal to take the computers and analyzers you need to record the data out to the field.  Microelectrode oxygen readings also change depending on the temperature, which is impossible to control in the field.  If you need any sort of fancy equipment, it’s often better to do your experiments in the lab.

Con: Space can be an issue

Working with insects is great because you rarely need a lot space to do your experiments.  For the hypothetical backswimmer scenario, a small lab (heck – a table!) has ample space to do a behavioral study.  But what if you’re working with deer or leopards or bald eagles?  You’re certainly going to have a much harder time bringing them into the lab, nor could you expect their behavior to be normal indoors.  In fact, you’ll probably have to sedate them to get them into the lab in the first place and then house them in small cages while they’re there to do anything with them.  If you’re planning to measure hormones in blood or are interested in body measurements, then this sort of thing is ideal.  If you want to study behavior…  Not so much!  You’ll get better results in the great wide outdoors than you ever will in a lab.

These are the sorts of things all biologists wrestle with when they decide how to answer their research questions.  You have to carefully weigh the pros and cons of any particular experimental design and choose the one that’s most likely to produce reliable results.  Sometimes it’s better to do your work entirely in the field or entirely in the lab, but other studies (like mine!) lend themselves well to doing both.  And thank goodness for that!  I wouldn’t want to spend all my time indoors.  :)

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