Observation and Bias in Biology

The following is a guest post by my friend Kent Fothergill. Read more of Kent’s musings at his blog, biologistsoup.

Observation is a key activity in scientific inquiry. People who work with insects can make many interesting observations from collected insects: distribution, phenology, etc. Observations can be documented and analyzed later from photographs. A collection of photographs can also yield information about: associations with other species, behavior, while providing the same information as collected specimens – as such photography is a new tool changing entomology. Of course, most observations are made using only human senses without photographic or specimen documentation, but all observations can be subject to biases.

Observer biases are our evolutionary legacy. Our brains evolved to process and interpret data based on patterns observed in previously processed data. Because of the vast amount of data flowing in from our five senses and our limited ability to focus on data, our brains let most data be background. Even the subset of data that we focus our attention on is filtered, who hasn’t taken a photograph and found something much more interesting in the photograph than the original subject (e.g., these mites on harvestmen)? All data, even the data subset we are focused on can be misinterpreted. When teaching scientific methods, my students always enjoyed the optical illusion exercises to demonstrate why objective analyses and accurate measurement are important.

Remember, that the brain also compares incoming data to previous data. This allows pattern recognition. Recently, Ted and I were blacklighting along the Mississippi River in Southeast Missouri. We found a pair of Elaphidion mucronatum (spiny oak borer) a very common insect in Southeast Missouri. So common that many would move on to other more interesting subjects at that point. The insects were in a mate guarding situation.  Because I had a name for the behavior, my brain put my observation in the mate guarding category. At this point I would have moved on, except Ted wished to document the subject with his camera rig, which meant I would do what any friend should: watch the insects while Ted ran to vehicle to get his camera so he would be able to photograph them. While Ted was gone things got interesting. The male was positioned above the female, who was more or less caged between his legs. The pair was moving in unison on the tree trunk with very little actual contact between the pair. This was interesting, but when the female E. mucronatum suddenly shot out from under the male ending up 10’ vertical below him on the side of the tree trunk I was stunned. The male covered this distance with amazing speed and recaptured the female. After a couple minutes the female again shot out from under went down a few feet and doubled back ending out of sight above the male. At this point the male remained motionless for a brief period. When Ted came back with his camera, I took my eyes off of the male to tell him about what I had seen, and the male had vacated the area. Later, on the very same tree, we saw a mate guarding pair (presumably the same individuals) coming down towards us.

I have viewed many mate guarding insects. Mate guarding is a male insect using its body to prevent other males from mating with this female. Evolutionary biologists will explain mate guarding behavior in terms of enhanced male reproductive success, and that is why mate guarding persists. I never questioned this explanation, but should have. The E. mucronatum observation caused me to see mate guarding in a new way and realize that mate guarding involves a male and female component – I know this seems obvious, but I had my own cultural bias to overcome in this regard. I had never considered that mate guarding could involve non-willing females.

Based on a 10 minute observation of a very common insect my new understanding of mate guarding now recognizes that mate guarding influences female fitness also. Mate guarding persists when it creates a change in fitness in the male and female such that there is a positive net change in fitness for reproductive output for all individuals involved. In the case I witnessed, there may actually be a reproductive cost for the female and that is why she tried to avoid/escape the mate guarding. I have much more to learn about mate guarding.

Science is a way of objectively seeing the world and testing what you have seen to approach truth. This observation of E. mucronatum was also a mirror that showed my cultural bias and how that bias influenced my interpretation of my observations. For me, this observation could be a watershed event.

The moral(s) of this story:

  1. Life is short: enjoy time in the field with friends.
  2. Pay attention. There are new and wonderful things to observe even in the common and mundane.
  3. Be aware of the biases that can keep you from the truth.
  4. Have fun out there!

Copyright © Kent Fothergill 2013

11 thoughts on “Observation and Bias in Biology

  1. Pingback: A middle-aged white male writes about cultural sex-based bias… | biologistsoup

  2. Kent here:
    James – there was no image (although I did take some horrible cell phone snaps), but I am glad you liked the story.
    Martha – It is good you liked the morals. Now go forth and do cool things!

  3. Oh well, I did see a nice image of mate-guarding cerambycids recently, and this post put motion to my memory of the image (if not the correct source).

    • JCT:
      You are very fortunate that we are moving AWAY from Missouri this month (to Wyoming). I’m starting to get quite a few vials of unidentified ANTS with which to irritate you, just as I do with Ted and Kent and beetles. Sorry I didn’t get the chance to meet you.


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