Month: July 2014

Aphids, ants, ladybugs, and wasps! Oh my!

We have a strange phenomenon occurring in our backyard. It started a few weeks ago when I noticed a pair of wasps engaged in a death match on our deck in the back yard. This event happened with regularity over the next few mornings, but I didn’t think much of it at the time.

Later that week we ate outside on the deck and were impressed by the huge numbers of wasps visiting our maple tree. I should say that my husband and I were impressed; our kids were very uncomfortable.

Fast forward to last weekend when I went outside to do some internet surfing on my tablet. The first thing that I noticed was the huge number of black ants running around our deck and all over the patio chairs and table. Being a biologist I also noticed that the table was covered with aphids and that the tree was infested with them. As I sat there for several minutes, it felt like a very mild rain shower was taking place. I realized that the aphids were excreting excess sugar in the form of honeydew and that there were so many of them that the screen of my tablet was covered in aphid poo in a matter of a few minutes! I’m guessing that the ants were going wild for the honeydew and that explains why they were running frantically all over the deck and furniture. Once I figured this part of the mystery out, I was also able to see a large number of ladybugs and their eggs in the maple tree. Ladybugs love to eat aphids and were taking advantage of this buffet opportunity.

But what’s the deal with the wasps? I’m not an entomologist, but there appear to be two species visiting the tree: the common yellow jacket wasp and something that might be a bald-faced hornet. Be doing some quick reading I discovered that the adults of both of these species eat nectar, tree sap, and fruit pulp. Perhaps the aphids have made tree sap readily available by feeding on the maple tree, or perhaps the wasps are eating the honeydew waste of the aphids deposited on the leaves. The other possibility is that the wasps are preying on the aphids and chewing them up to feed to larvae back at the nest. The wasps don’t appear to be a parasitoid species preying on the aphids.

It’s very cool as a biologist to see a food web occurring in your own backyard. This phenomenon has also served to remind me of the importance of observations in solving biological mysteries and testing hypotheses.

 

Flipboard: Finding current science news stories for use in your classroom

In the courses that I teach I’m always on the look-out for current news stories that are directly related to course content. One source that I’ve found to be a great source for these particular stories is the app Flipboard. They have a science section which is a great source for stories being covered by the popular media. Below are a collection of stories aggregated by the app within the past 24 hours.

If you teach a virology course, spending some time talking about the recent discovery of vials containing smallpox in Maryland  would be directly applicable to the course content and will likely grab the attention of your students.

Talking about plant dispersal in your botany course? EarthSky has written a great summary of an article about how migrating Arctic shorebirds are spreading mosses and liverworts  to new areas of North and South America. The plants may hitch a ride in the feathers of the birds.

Really into amphibians and conservation biology? Check out this Associated Press article on the hellbender; a giant salamander that is rapidly declining in population in the United States.

If invertebrates are more your thing, you’ll be amazed to watch the video of a purple siphonophore in this article from the Huffington Post.

I do a section in my Endosymbiosis class where I talk about all kinds of amazing and gross parasites. Talking about how a targeted eradication effort has almost wiped out the guinea worm in Africa  would be a neat way to talk about how public health efforts are changing our ecosystems and the natural world around us.

I’ve just given biological examples above, but the app collects stories related to many areas of science and engineering that could be used to bring your course content to life.

Feel free to share other news story resources that you use for course material or for general interest in the comments below.

 

 

Using Popular Sci-Fi films to Illustrate the Concept of Endosymbiosis

I teach a fourth year undergraduate course on the origin of life on Earth and endosymbiotic theory. I use my first lecture as an opportunity to highlight some of the interesting material that we will be covering that semester and to get the students hooked on the class. I do this by talking about several examples of endosymbiosis that are present in popular science-fiction movies.

 

I have a very broad definition of endosymbiosis. I classify it as two organisms living together where one organism lives inside of or is contained by the other organism. Endosymbiotic relationships exist on a spectrum of whether they are inert (e.g. not harmful or helpful), mutualistic (e.g. helpful to both parties), commensal (e.g. helpful to one, but not hurtful to the other), and parasitic (e.g. detrimental to one and beneficial to the other).

 

The first example that I discuss in class is from the 1979 classic film Alien. I didn’t see this film until I was a teenager and by then several sequels had been released. The first film in the franchise is a great example of how to use suspense effectively to really scare your audience. There is a classic scene in this movie that will ensure that you never look at eating in a mess hall or cafeteria the same way ever again. Long story short, the humans in this film serve as very effective incubators for the alien in a grisly endosymbiotic relationship. The relationship comes to an end in a very messy way. Unfortunately using this reference dates me a bit; usually only 2 out of 44 students have seen the film when I ask for a show of hands. I do have several students tell me after a few lectures that they ended up watching the film and liking it, so Ridley Scott’s royalties continue to serve as a revenue stream for him.

 

The second example that I use is from the 2009 film Avatar. The aliens in the film, the Na’vi, ride dragon and horse- like creatures. There are several short scenes in the film where a direct interaction between the Na’vi rider and direhorses or banshees is achieved by cilia like structures and a neural interface is created. I talk about this type of cellular interface as an interesting example of communication between two different endosymbionts.

 

The last example that I use in class is from the 1999 film The Phantom Menace. There is a scene in the film where Qui-Gon Jinn is testing Anakin Skywalker’s blood for midi-chlorians. Midi-chlorians are described as intelligent, microscopic life forms that allow their hosts to detect and use the Force if present in high enough quantities. Anakin’s midi-chlorian count is the highest ever detected and we all know how that turned out!

 

I use these fake examples of endosymbiosis from film to illustrate and discuss some of the concepts involved in endosymbiotic theory. They represent an interesting way to bring popular culture into the classroom and hold the interest of my students.

 

I’m always on the look-out for other examples of endosymbiosis in film or television; please leave any ideas in the comments!