Do I Eat Bugs?

lobster

A lobster. Image taken from Wikipedia.

Several years ago, Dave Barry ran a column that instantly became my favorite.  In it, Barry discusses why he doesn’t eat lobsters and cites some then current science to support his position.  It is a fine piece of persuasive writing if you ask me!  You can read the whole column on the Miami Herald website, and I highly recommend that you do, but the best part of the column for me was the comparison Barry drew between insects and lobsters.  Of particular interest to me was the section where he suggested that he wouldn’t eat a lobster because it’s basically an oversized insect.  I couldn’t agree more.

When people learn that I am an entomologist, I invariably get questions related to my work. People ask me to ID insects for them and lots of people ask me why I am interested in insects (usually in a disgusted or flabbergasted tone).  These are my #1 and #2 most frequently asked questions.  The #3 most frequently asked question is this:

Do you eat bugs?

This question baffles me.  I don’t get where the question comes from, but I get it all the time.  I accept that entomologists are probably slightly more likely to eat insects than most Americans, but why do so many people instantly jump from “entomologist” to “eats bugs?”  Are people who study, say, condors constantly asked whether they eat their birds?  People who study mice or wolves or bison?  Why do so many people assume that I eat bugs just because I study bugs?  If anyone has any insight into this question, by all means leave a comment.  I want to get to the bottom of this.

For the record: I do not eat bugs, at least not on purpose.  Personally, I find the idea repulsive.  Bugs have exoskeletons, so they’re crunchy on the outside and mushy on the inside.  I don’t like that combination at all.  But I’m a picky eater in general and the most squeamish meat-eater you’ll ever encounter.  Case in point: I don’t eat chicken wings because by the time I pick off all the skin, bones, fatty parts, and tendons, i.e. all the parts I consider inedible, there’s hardly anything left to eat, and certainly not enough to warrant all the work I put into getting it.  If I’m not willing to eat a “normal” American food like chicken wings, an insect is so not going to happen.

I have a very long list of things I refuse to eat, and invertebrates top the list.  These include lobsters, crabs, crayfish, mussels, squid, scallops, clams, and insects.  I also don’t eat anything aquatic (ducks, frogs, fish, turtles, alligators, beavers – and yes, some people do eat beavers!  I can pass along the sweet pickled beaver recipe I gave my sister a while back as a joke if you don’t believe me) because I think they are all vile.  I will occasionally eat a pile of popcorn shrimp (which are delicious if I can trick myself into forgetting that they have exoskeletons long enough to eat them) or a few fish sticks (because fish isn’t vile if eaten in very tiny quantities and buried in breading), but I am otherwise opposed to all swimming and/or crawling foods.  Yuck…

Aside from being a picky eater, I tend to be a bit sarcastic.  Okay, okay.  I’m a lot sarcastic.  This means that when I get what I think is a crazy question (such as, oh, do you eat bugs?) full sarcasm mode ensues.  I get this question so many times that I actually have a response ready to go:

“No, I do not eat insects.  Do you eat lobsters?  Cause they’re basically the same thing…”

Many people aren’t aware that this is essentially true.  Consider these two points:

  1. The closest relatives to insects, based on DNA evidence, suggest that insects are most closely related to, wait for it, crustaceans!  That’s right.  My humble water bugs are likely a small step away from their aquatic brethren the lobsters, crabs, crayfish, shrimp, and pill bugs (or roly polies or sow bugs – whatever you happen to call those cute little land crustaceans that curl into a little ball when disturbed in your part of the world).   So, in essence, insects and lobsters are about equivalent when it comes to the culinary experiences they provide.
  2. There are next to no marine insects, that is insects that live in the ocean.  Some scientists have suggested that this is because insects originally evolved on land while crustaceans evolved in the ocean.  When they decided to crawl back into the ocean, insects discovered that all of the good places they needed to live were filled up with, that’s right: crustaceans!  The habitat and resource requirements of marine crustaceans are so similar to insects that they were able to prevent insects from invading their salty homes.  Thus, insects and lobsters are about equivalent when it comes to the things they need to survive.

These two points together suggest to me that lobster = insect.  Both of them are equally inedible as far as I’m concerned.  Dave Barry had it right!

can of water bugs

A can of giant water bugs. Photo copyright Adam Vandenberg and taken from http://www.flickr.com/photos/adamvandenberg/.

That said, I am not opposed to other people eating insects.  I will happily watch someone else eating fried ant larvae or chocolate covered mealworms or one of those horrible scorpions embedded in a lollypop.  I won’t even cringe while I watch or make snide comments!  Just because I’m way too squeamish to eat an insect myself doesn’t mean other people shouldn’t.  Americans have a huge hangup about entomophagy (i.e. consumption of insects by humans), but lots of other cultures include insects in their diets for one simple reason: insects are incredibly nutritious.  They’re full of excellent proteins and several species are supposed to be quite tasty.  The insects I study, the giant water bugs, are widely and happily consumed in southeastern Asia.  They’re served fried or steamed and you can get them freeze dried or pickled in cans (see photo at left).  In Thailand they’re often ground up and stirred into a chili paste to make a sauce.  The people of Vietnam consider a secretion produced by a Lethocerus species a delicacy.  It fetches very high prices at markets and may be partly responsible for conservation efforts related to giant water bugs in Vietnam.  I’m glad someone else has tried water bugs and discovered that they’re incredibly tasty.  But I’m still not eating one myself.

I have a can of Lethocerus in my office, the exact same brand as in the photo.  It sits there unopened, but I love it anyway.  I only know what’s inside because I saw one opened on the Food Network during a segment about the annual Explorer’s Club banquet a few years back.  One of the foods served, among a hundred or so other random things that most people wouldn’t even consider eating, was my can of freeze dried Lethocerus.  There’s no point to popping the can open if I’m not going to eat them myself.  Besides, they make a great conversation starter at outreach events!  Stash a can of Lethocerus next to a live Lethocerus swimming in a jar and you earn yourself a veritable river of people asking questions and eager to learn more about these fantastic bugs.

So there you have it, the answer to my third most frequently asked entomology question, the one that will always intrigue me.  And because I find entomophagy fascinating, expect a post on the subject soon!  In the meantime, I’m curious about how many of my readers might eat an insect, so today I leave you with a very brief poll.

1

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.

Aquatic Insects and Water Quality

water sampling

The Dragonfly Woman recording data during a sampling trip to an effluent stream. Photo by Dave Walker.

I’ve decided to put off talking about my damselfly research another month or two so the post is closer to the paper release date, so I’m going to talk about another subject today: aquatic insects and water quality.  In my second year of grad school, a professor for a class I was taking recommended that I apply for a job.  A month later, I had a second job in an aquatic ecology lab and was working as an aquatic sampler and insect identification guru.  The project I was hired for originally was for the Environmental Protection Agency and focused on the impacts of effluent (treated wastewater) on the insect populations downstream of wastewater treatment plants in Arizona.  I can’t say that sampling for the project was pleasant and I can attest to the fact that wearing chest waders in poorly treated, reeking wastewater when it is 110 degrees in the shade is quite awful.  However, the project taught me firsthand just how much of an impact water quality has on aquatic insect populations and it is a subject I find fascinating.  In fact, my work in my second job has helped direct my plans for my research program once I have completed my doctorate.  I haven’t talked much about my second job yet in my blog and it’s time to rectify this!  Today I’m going to introduce the subject of aquatic insects and water quality.

Arizona  has a lot of problems with its water.  There are huge demands placed on the little water that is available and streams and rivers have been sucked dry by farmers and growing cities over the last hundred years.  This means that in some sections of several rivers there would be no flow at all if it weren’t for wastewater treatment plants releasing effluent.  So just how to insects respond to wastewater?  The short answer is this: not well.  Aquatic insects are typically adapted to a particular range of conditions.  If those conditions change, such as when effluent is dumped into a stream, the insects must often move to a different habitat or die.  Other insects, things that are very tolerant to polluted waters, may move into the area in their place.  You can therefore see a huge shift in the types of insects living in a clean, relatively pristine stream relative to an effluent dominated stream (a stream nearly completely or completely made up of effluent).  Many types of insects simply can’t live in environments with low water quality – and those that can tell you a lot about how terrible the water quality really is.  In fact, aquatic scientists often use aquatic insects as biological indicators of water quality.  That was exactly what we were doing in the effluent project, using insects to tell us about the quality of water in effluent dominated streams.  I’m not going to go into detail about that project today.  Instead, I’ll illustrate the differences in the insect populations between two streams in the Tucson area, one effluent dominated stream (the Santa Cruz River) and one mostly clean water stream (Sabino Creek in Sabino Canyon) so you can see the shift from dirty water insect populations to clean water populations.

Let’s take a look at an effluent stream first, a dirty stream.  The Santa Cruz River is one of the major “rivers” in Tucson and it is dry most of the year along most of its length.  However, it always flows downstream of the wastewater treatment plants.  The Santa Cruz River is therefore 100% effluent for most of the year.  Effluent, even when it is very well treated, has all kinds of bad things in it.  In my area, the nitrogen levels of the waters released from treatment plants are very high.  Scientists have also discovered many compounds that humans secrete in our wastes, such as pharmaceuticals, flame retardants that are on our clothing, triclosan (an antibiotic used in antibacterial soaps), and many other nasty chemicals.  These don’t get cleaned out of the water with current treatment techniques, so all those chemicals end up in the streams when water is released from treatment plants.  In essence, the biota living in the streams below wastewater treatment plants are bathing in a stew of antibiotics, birth control chemicals, detergents, etc.  You can imagine why this might be a problem.  My labmates have found many of these chemicals in the Santa Cruz River water.  So what kinds of insects do you find there?  We recently took a reporter for the Arizona Daily Star to sample from the river as part of a story about the wastewater treatment plant.  These are the insects we found:

blood worms

Bloodworms, larvae of the non-biting midges (a type of fly). This photo made the front page of the newspaper the day the article ran!

Ah, the lovely bloodworm.  And notice that ALL of the insects in this image are bloodworms.  Not all bloodworms are a sign of troubled waters so you can’t simply say that bloodworms = low water quality.  However, if you find tons of bloodworms and nothing else in a stream, that’s usually a bad sign.  Bloodworms get their name from their red coloration (it has been mostly broken down in the image due to the preservatives used – they’re flaming red when they’re alive) and that red coloration comes from a chemical bloodworms have that almost no other insects have: a hemoglobin-like compound.  If you want to read more about bloodworms and their hemoglobin, please read my post on aquatic insect respiration.  For now all you need to know is that the hemoglobin-like compound allows these insects to live in very low oxygen environments.  Thus, the sheer abundance of these insects and the lack of other insect species tell you something important about this stream: there is hardly any oxygen in the water at least some of the time.  The chemicals in the water probably contribute to the overall inhospitability of the river for insects as well.  Thus, the insects in the stream tell you that this stream has poor water quality.  We found this to be the case at all of the effluent streams we sampled during the EPA study, but this particular wastewater treatment plant had the fewest species of aquatic insects downstream of the plant of all of the streams we tested.

Now let’s compare the low quality stream to one with high water quality, Sabino Creek.  Sabino Canyon is one of the most popular outdoor spaces in the Tucson area in part because it has a gorgeous clear stream that flows through most of the canyon.  We went to Sabino Creek to sample right after we sampled in the Santa Cruz, and these are just some of the insects we found in the creek:

backswimmer

Backswimmer (Family: Notonectidae)

dragonfly

Dragonfly nymph, a clubtail dragonfly (Family: Gomphidae)

damselfly

Damselfly nymph, a spreadwing damselfly (Family: Lestidae)

Hellgrammite (Corydalus cornutus)

Hellgrammite (Family: Corydalidae)

Creeping water bug

Creeping water bug (Family: Naucoridae)

dragonfly

Dragonfly nymph, a skimmer (Family: Libellulidae)

Notice the difference between this stream and the effluent stream?  Look at how many more species there are!  And some of these, including the hellgrammite and the clubtail dragonfly, only live in pretty clean water and need a lot of oxygen.  Even if you didn’t know that though, you could tell that this is a fairly clean water stream simply by looking at the number of insect species living in it.  There is one caveat, however, when comparing the Santa Cruz River to Sabino Creek.  The river is in the Tucson valley and is located at a lower elevation than Sabino Creek, which means that the types of insects you find in the stream would likely be a bit different even if they had the same quality.  Still, if you compare other effluent streams at similar elevations, or even the Santa Cruz River below the wastewater treatment plant upstream of Tucson at Nogales, it is obvious that the section of the Santa Cruz flowing through Tucson is really nasty.  Sabino Creek is comparatively very clean.  And, the insects in the stream can tell you just how clean the water is because they are excellent indicators of water quality.

This trend, that clean water has much higher insect diversity than polluted water, seems to hold true throughout the world in the majority of aquatic habitats.  For this reason, insects have become very important in water quality studies.  By collecting insects and identifying them, a scientist can say some very profound things about the water quality in that environment even if he doesn’t take any other measurements.  I’ve personally done a lot of work using insects as indicators of water quality through my second job and this work has profoundly impacted how I think about aquatic systems and the insects that call them home.  I’ll definitely be revisiting the topic in the future.

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.

Studying Invertebrate Behavior on YouTube

image from class

An experimental setup in my recent insect behavior class. The students were studying how water temperature impacted respiratory rate in the giant water bug Abedus herberti.

As a lab instructor for an insect behavior class, I use a lot of live insects in my class.  The students enjoy working with them and are generally happy they don’t have to watch videos the entire semester.  Trust me – watching hours and hours and hours of insect behavior video can get really dull really fast.  Live insects are definitely the way to go for a class where most of the students do not have the level of patience that I do.

Unfortunately, the class is held in the spring, so there’s just not many insects out until the end of the semester.  This means that my students work mostly with my favorite insects, the aquatic insects, which is good.  However, it also means that they have a fairly limited variety of things to work with, i.e. things that overwinter as nymphs or adults.  I am able to collect a decent variety of aquatic insects during the winter in Arizona.  Still, there is one lab that would be SO much better if we had a bigger variety of insects to work with: the predator lab.

I developed the predator lab four years ago when my students at the time were constantly begging to put two hungry predators together and watch what happened in the ensuing death match.  (Did I mention that my students are college seniors and grad students and NOT 5 year olds?)  In the interest of turning this morbid curiosity into a teachable experience, the predator lab was born.  In it, I have the students feed several different predators and compare and contrast their feeding behaviors.  They have to watch how the insects capture and devour their prey and describe how they do it in detail.  They also have to tell me whether the insect is a sit and wait predator (they stay in one place and wait for food to swim, walk, or fly by), an active predator (they purposefully hunt down and attack their prey), or something else.  This way, the students get to watch several predators capture prey and eat it, fulfilling their need to promote death and destruction, but they are doing it in some meaningful context.

The predator lab is my favorite.  It requires a lot of work on my part to collect the insects and prepare the containers and prey items for the bugs, but the students get so into the activity that I can’t help but love it.  Even my quietest class, the class I just finished last month, got into it and actually made some noise in class for once!  And things get even better toward the end of the class period when they have finished their work for the day and I let them feed the things that don’t survive well in the lab to my water bugs or to each other.  This is the treat at the end of the semester, their reward for making it through what I consider a very work-intensive course: the death match they’ve been eagerly hoping to set up all semester.  This year there was also a water bug eating a fish to watch (click on the link to see the video!).  That really got the students excited.

Unfortunately, this year was a terrible year for aquatic insects in my part of Arizona.  We got a ton of rain during the winter and there was extensive flooding in the mountain streams that washed out the insects.  The populations didn’t rebound very quickly and there was hardly anything in the streams even several months after the floods.  I was hard pressed to get enough insects for my class this year and we ended up with a measly three types of insects for the predator lab this year: some small predaceous diving beetles, some dragonfly nymphs, and some of the smaller giant water bugs.  It doesn’t take very long to feed a hungry insect, so I brainstormed ideas for activities to fill up half of the class period.  I eventually settled on something I knew the students would love: showing some of the spectacular videos of predatory insects on YouTube.

YouTube is a rather amazing repository of insect behavior data.  A lot of the video is collected by amateurs and many of them know very little about the insects they’ve filmed.  That doesn’t matter – there is some great stuff on there if you know where to look!  For my class, I chose some of the most showy videos I could find.  My students had spent the semester watching live insects.  A video has to be amazing to hold my students’ interest at the end of the semester and the 8 videos I settled on fit the bill well.  And because they are too good not to share, I am posting them here so that everyone who reads my blog can see them too!

Army ants:

Damselfly eating another damselfly – check out the mouthparts moving!:

Preying mantis vs. mouse – and the mantid wins!:

Centipede vs. mouse – and the centipede wins!:

Spider captures and kills a bat:

Antlions (are awesome!):

Orchid mantid captures fly:

I can safely say that this was an excellent way to kill some time in class.  The students loved the videos (there were several collective cries of “Whoa!” during lab that day!) and actually learned something in the process.  A few of them even referenced the videos in their lab write-ups!  It was so successful that I think I will do this again the next time I have an opportunity to teach a behavior class, even if I do have a lot of animals to use in class.  It was great for the students to get to see some things we couldn’t possibly duplicate in class and let them see some more insects in action after their regular lab activities.  It was a great way to finish the last lab of the semester.

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.

Notes From NABS Day 5

meeting logoPhysical, Chemical, and Biological Changes Along the Continuum of an Agricultural Stream: Influence of a Small Terrestrial Preserve

Well, I didn’t quite get this post done the day I meant to, but my day ended up being quite busy.  However, the NABS/ASLO joint meeting of 2010 is now officially over!  That means this will be my last NABS post until I go to another conference.  It’s nice to be back home!  Meetings are exhausting and melt your brain after a while.  They’re fun, but they’re intense – and I never get enough sleep.  No matter how much I enjoy a meeting, I’m always happy to get back home and sleep.  And, if I come away from the experience without any new communicable diseases, I’ll consider it a success.

I’m going to skip the Things I Leaned section for today and jump right into the last talk.  Today, my focus is a talk by Dr. David Houghton that was given on Day 3 of the conference.  Dr. Houghton is an entomologist and Associate Professor at Hillsdale College.  Hillsdale is a small liberal arts college (even smaller than the one I went to as an undergrad!) and Dr. Houghton is in the department of biology there.  Sadly, there aren’t all that many people from these sorts of schools at most of the meetings I go to.  This is doubly sad because Dr. Houghton’s presentation was really interesting and made some excellent points.

In the area in southern Michigan where Dr. Houghton completed his study, the streams used to be surrounded by a wide strip of dense vegetation (the riparian zone).  The area is now an agricultural region.  This means that, rather than large trees and plants that require a lot of water filling the space adjacent the streams, the native plants have been removed and the agricultural fields go right up to the banks.  This has several implications.  The lack of trees means the water is warmer than it was before the trees were removed because there isn’t as much shade on the water.  A lot of chemicals such as pesticides and fertilizers end up in the water any time water flows over the fields and into the streams (i.e. during rains, heavy irrigation, etc).  Those chemicals decrease the water quality, which in turn impacts the plants and animals that live in the water.  Overall, the water quality decreases and with it the number of species that can live in the river.

In general, this situation isn’t good for the stream or any of its biota.  The river needs the forested areas for everything to work properly.  Removing the riparian area means that things in the river change and the “health” of the river goes down.  Stream health is a somewhat vague concept that I don’t want to get into here, but it is essentially a measure of how close to naturalistic conditions an ecosystem is.  Dr. Houghton’s talk began with this introduction.  Then he asked a question: are the small forested areas that are still available along southern Michigan’s streams capable of improving the water downstream so that the area downstream more closely resembles conditions without the influence of agriculture?  This has important implications for conservation of aquatic species.

Dr. Houghton’s study was conducted in the St. Joseph River in southern Michigan.  Like other rivers in the region, the St. Joseph has agricultural fields along the majority of its length with small forested areas near the headwaters.  In particular, Dr. Houghton was interested in one section of the river that had a small terrestrial preserve where the riparian area remained intact.  The river running through the preserve looked better than the area upstream, so he thought the water flowing through the area might be improved such that insects downstream of the preserve would fare better than the insects above the preserve.

To study this, Dr. Houghton chose six sites in the St. Joseph River from which he collected water and insect samples.  Two sites were above the preserve, two were within the preserve, and two were further downstream.  He measured several parameters of the water itself, including the temperature, dissolved oxygen, pH, and conductivity (effectively a measure of the amount of salt compounds in the water).  He also measured the insect populations by collecting adult caddisflies at light traps near the river.  Measuring the water parameters would tell him whether the water running through the preserve or downstream of the preserve was better than the water upstream of the preserve.  Because caddisflies are aquatic as larvae and live in the water for most of their lives, they are strongly impacted by water quality and are excellent indicator species.  Counting the number of individual adults and the number of species (also known as species richness) that came to the light traps would tell Dr. Houghton something about how “healthy” the river is.

His results were interesting.  There was no difference in any of the measurements of water quality Dr. Houghton collected above and below the preserve.  This meant that the river is an agricultural stream for its entire length and the preserve did not improve the water quality downstream.  There were two water parameters that improved within the preserve: the temperature (it went down) and the amount of dissolved oxygen (it went up).  These two changes can likely both be attributed to the amount of shade the river receives in the preserve versus the areas outside.  Shading the water causes the temperature to go down because less sun hits the water.  This in turn causes the dissolved oxygen to go up because cooler water holds more oxygen than warmer water.  However, once the water flowed back out of the preserve, the temperature and the dissolved oxygen went back to the levels seen above the preserve.  The preserve did not appear to be improving the water quality in the river.

Similar results were found using the insect samples.  Dr. Houghton found that 7 species of caddisflies made up 90% of all of the specimens coming to the light traps both within and outside the preserve.  These 7 species all feed in similar ways (they are collector-gatherers and they eat things that are floating in the water, like leaf particles and floating algae that are of the appropriate size) and have the same level of tolerance to pollution.  So, it appears that the majority of the caddisflies in the river were about the same throughout, again suggesting that the preserve didn’t do much to improve the quality of the river.

However, Dr. Houghton did detect one important difference between the caddisflies in the preserve compared to those outside: there were more species of caddisflies inside the preserve, so the species richness improved.  22 species of caddisflies were found only in area of the river where it flowed through the preserve.  Most of these caddisflies fed in a similar way (they are shredders, or insects that tear leaves and algaes into pieces small enough to eat – an important component of decomposition in aquatic systems) and the remaining species were ones that required cooler waters than those found outside the preserve.  None of these species were very abundant and in fact a few of them were represented by only a single specimen, but the species richness was definitely improved within the preserve compared to outside.

Dr. Houghton ended his talk with a question: is the river “healthier” because of the presence of the preserve?  He suggests that the answer to this question depends on what measure of health you are using.  The preserve clearly didn’t change the water quality so that the section downstream of the preserve was different from the area above.  If your measure of river health is whether the water quality and caddisfly populations downstream of the preserve are better than those above, then the preserve does not have any effect.  This could give some policy makers the idea that it’s okay to rip those last few preserves out, making space for more agricultural fields.  However, if your measure of river health is species richness, the presence of the preserve had a huge impact.  The river above and below the preserve had many fewer species of caddisflies than the area within the preserve.  Clearly the preserve is acting as a refuge for species that are unable to live in the more harsh conditions outside of the preserve.  Thus, if your goal is to maintain diversity in the stream, the preserve is very important.  In fact, building new forested areas along the water might further improve the diversity of the river even further.

I thought this talk was excellent.  It was a simple project, but it did everything it needed to accomplish.  Dr. Houghton’s talk also highlighted a couple of important points.  First, when looking for the biological impacts of a system on a species, you need to identify which measurements of health you want to use.  Second, it is good to consider multiple measurements of health within a system.  It would be tragic for any study to say that forested areas near a stream aren’t necessary because they don’t improve the water quality downstream.  I think what makes Dr. Houghton’s study great is the fact that he identified the changes in the species richness of the forested preserve, which showed that the preserve really did have an impact on the river system, if only in the area within the preserve.  It wasn’t exactly the one he might have expected or hoped for, but it does suggest that forested preserves are valuable to river systems and should be protected so that species diversity within the river is maintained.

And that wraps up the Notes from NABS series!  I hope you all enjoyed the glimpse into the research that is currently happening in the aquatic sciences and learned some new things.  Scientific conferences are an excellent place to gain new insights, think about things in new ways, or learn about things you’ve never even considered.  Hopefully I have passed some of these qualities on as they’re just too good to keep to myself.

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Posts in this series:
Day 0 – Introduction to the Series
Day 1 – Invasive Crayfish
Day 2 – Giant Water Bug Dispersal
Day 3 – Dragonfly Captive Rearing
Day 4 – Integrating Service-Learning Programs into College Courses
Day 5 – Impact of a Small Preserve on Stream Health

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.

Notes from NABS Day 4

meeting logoIncorporating Service Learning Into an Introductory Limnology Course

Greetings from NABS Day 4!  Tomorrow is the last day of the conference, so I’ll only be making one more post in this series.  I’m also headed home, and a bit earlier than originally planned.  A combination of sleep deprivation and general physical and mental exhaustion due to extensive traveling over the last few weeks (I was gone almost a week right before the conference began) has convinced me that I should go home in the morning, skipping the talks on the last day of the conference.  I’m driving home, so it’s important that I travel during the period when I am most alert, which means missing the talks.  So, I will be presenting something from one of the first four days of the conference when I post my final entry for the conference on Saturday.  What can you do?

Things I learned:

— High school students have a lot of fun going out into the field to collect data (though this shouldn’t come as a surprise – my favorite biology lab in high school was one where we documented the ecosystem of a marsh in Colorado, the same marsh where I eventually did my undergraduate biology thesis!)
— Aquatic insect species that are found in many areas across the landscape are usually found at about the same altitude while insects that are found in a wide range of altitudes are typically only found in a small geographic area.
— This is really re-confirming something for me:  conferences are exhausting!

On to my favorite talk of the day!  I attended the Education in Aquatic Sciences session today because this subject is near and dear to my heart.  I LOVE teaching, so any time I can learn more about how to do it better, you know I’ll be there in the front row.  (Okay, okay – so, I was in the second row…)  My favorite talk of the session ended up being my favorite talk of the day, partly because it was an interesting talk and partly because the speaker, Dr. Frank Wilhelm, was completely inspiring.  Dr. Wilhelm is a professor in the University of Idaho’s Fish and Wildlife Resources Department and teaches a course in introductory limnology to undergraduate students.  His talk focused on a service-learning project that he has incorporated into his class and he described how it works.

Service learning is defined as a method of teaching, learning, and reflecting that combines classroom curriculum and meaningful service throughout the community.  In essence, service learning projects allow students to doing something hands-on that is also worthwhile to the community.  Dr. Wilhelm described service learning as a powerful, motivating, and effective approach to teaching and learning and believes it can be broadly applied in college courses focusing on field-based sciences.  He also believes that it engages students in a way that isn’t possible via other teaching methods and helps the students form a strong connection between what they learn in class and the real world.

Here’s how the service learning component of Dr. Wilhelm’s intro limnology course works.  First, he finds someone or a group of people in the community that have a problem they want solved or a question they want answered.  That person or group then becomes the partner for the class that semester.  Dr. Wilhelm gave an example of a partner from the last class he taught.  In his area, there is a small lake that is surrounded by ritzy homes.  However, the lake was absolutely full of vegetation, so full that it was completely useless for any other purposes such as fishing or boating.  The neighborhood asked Dr. Wilhelm to have his students tackle their problem and became the class service learning partner for the semester.

Students are told at the beginning of the term that they will be doing a service learning project as part of the course.  It is a required activity that ends up taking up the final 1/3 of the lab periods of the course.  During the first week, the students are put into groups that become their team for the semester and the entire class is introduced to the problem.  The second week, the partner presents the problem to the class so that the students know the person/people they are helping and the problem they are trying to solve.  They then identify subsections within the main problem that individual groups can tackle during the course.  Teams decide which subsection they want to focus on and define clear objectives, develop methods, make lists of equipment they require (made available by Dr. Wilhelm from his personal supply), and develop a budget that will help them accomplish their goal.  Dr. Wilhelm allows his students nearly complete freedom to decide which aspects of the problem they wish to tackle, how they wish to tackle it, and what sort of data they will need to collect.  His only requirement is that they have to work toward solving the overall goals of the project.

Then he sets them loose out in the field to do their projects!  By his account, this part is a little chaotic, but the students generally have fun and are learning valuable things while they work.  Dr. Wilhelm also said that students use their travel time to discuss issues related to the project, so there isn’t any downtime – they are constantly learning.

Back in the lab, the students analyze the data they collected in the field and make conclusions based on their results.  Then they present their part of the project to the rest of the class in teams.  The students combine their efforts to create a report that they will present to the partner.  And then they present their data to the partner in person, making suggestions for how the partner might solve their problem.

Dr. Wilhelm said that this sort of project is fairly easy to incorporate into a class that could conceivably have a field component.  (I can imagine how well it would fit into my insect behavior and aquatic entomology labs!)  He said that all you need to get started is to identify a partner for the semester, identify the areas of expertise for which you have sufficient knowledge to successfully guide students toward solving the partner’s problem, and spread the word about the program to get people interested.

Dr. Wilhelm believes the program has been a big success.  The partners have been happy with the information the students have provided them.  The students themselves tell Dr. Wilhelm that they really enjoy the project and think it’s the best part of the class.  Dr. Wilhelm thinks his students have become more engaged in the course since he introduced the service learning project as well.  Perhaps the best measure of success is that, in a difficult senior level undergraduate course worth 4 credits that starts at 8AM, he has nearly 100% attendance!  This just doesn’t happen.  He attributes this spectacular feat to the service learning project experience.

Although the talk was simple and not a scientific research talk, I really loved this one.  If nothing else, Dr. Wilhelm obviously cares about his students deeply and wants them to succeed.  He puts a lot of effort into his teaching and is clearly excited by the teaching component of his professorship (a somewhat rare trait at the big public universities!).  It was so inspiring to listen to him talk about his program and how involved the students become, how much they care about what they’re doing during their service learning project.  I’m hoping to incorporate some of the same things into my own courses sometime!

Tomorrow I’ll finish up Notes from NABS with a description of a talk I heard on Day 3 that focused on the effects that a small wildlife preserve has on a river in southern Michigan.  The vegetation that would naturally surround the river (called the riparian area) has been entirely replaced by agricultural fields – except for the area where it flows through the preserve.  Want to know if this preserve helps improve the quality of the water before it flows downstream?  Check back tomorrow!

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Posts in this series:
Day 0 – Introduction to the Series
Day 1
– Invasive Crayfish
Day 2 – Giant Water Bug Dispersal
Day 3 – Dragonfly Captive Rearing
Day 4 – Integrating Service-Learning Programs into College Courses
Day 5 – Impact of a Small Preserve on Stream Health

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.

Notes from NABS Day 3

meeting logoEggs to Adults: A Captive Rearing Program for an Endangered Dragonfly

Wow!  Day 3 of the NABS/ASLO meeting is already over!  It was a great day for me.  There was a whole session on aquatic insects and that’s always a good thing, at least if you’re me.  Day 3 was the day of the banquet, so I got to have a huge dinner of delicious Mexican foods.  I love Mexican food!  (Actually, I’ve had Mexican food for almost every meal since I’ve been here…  I’m an addict!)  I had a lovely dinner conversation with a professor from Wheaton College who has the exact sort of professorship that I hope to get.  She was encouraging and had some very helpful advice for my impending job search that is going to be useful.  She was incredibly nice as a bonus.  And, I got second place in the photo contest for this photo:

giant water bugs

The giant water bug Lethocerus medius hatching

There were over 50 entries, so I’m feeling pretty chuffed about it.  My photo sold during the silent auction for the photos in the competition too.  Excellent way to end an already good conference day.

Some things I learned:

—  There is a research center in Minneapolis called the St. Anthony Falls Laboratory where researchers have built an artificial stream that can be precisely controlled, allowing researchers to do work that isn’t possible in natural streams.
— Iraq had an enormous marsh in the southern part of the country that has been used by people for thousands of years – until US soldiers used it as a hiding place during the first Gulf War.  The Iraqi’s drained it and burned the vegetation to force the soldiers out.  Locals in the area recently began breaking down the dams used to divert the water so that water is once again filling the marsh.  Crazy!
— Freshwater clams and mussels are among the most highly endangered animals in the world.

And speaking of endangered species, I thought I would discuss a talk I heard today the relates to an endangered species.  It was hard to choose a favorite talk today because I really loved several of them, but considering this blog is The Dragonfly Woman, I thought it appropriate to write about the dragonfly talk I heard.  Behold Somatochlora hineana (also known as the Hine’s emerald dragonfly):

Somatochlora hineana

Somatochlora hineana. Photo copyright 2005 by Glenn Corbiere and taken from http://dragonhunter.net/somatochlora_hineana_m.html.

This is one of the most rare dragonflies in the world.  It is in fact the only dragonfly on the endangered species list.  According to the woman giving the talk, Rachel DeMots of the University of South Dakota, this species used to be found in several states in the U.S.  In recent years, it has experienced a contraction in its home range so that it is currently found in only Wisconsin and Michigan.  The populations in these two areas are at high risk of extinction and are of great concern for conservationists.

Endangered insect species often become the subjects of captive rearing programs.  By capturing at least a few males and females in the field, researchers can bring them into the lab, mate them, and rear the eggs into new adults.  Insects in captive rearing programs are kept safe while they are growing and are then released back into the wild as adults to augment the tiny populations left in the wild.  (This has occurred in non-insect species as well, such as the California condor and the black footed ferret.)  For a more detailed account of one of these programs, I highly recommend reading the section on the Lange’s metalmark butterfly (Chapter 11 – Butterfly Ressurection) in the excellent book The Dangerous Lives of Butterflies by Peter Laufur.  It goes into detail about how the captive rearing program of the Lange’s metalmark, which had a total population size of only a handful of individuals living in a tiny area known as the Antioch Dunes in California, might help save this species from extinction.

But back to the dragonflies!  The Hine’s emerald population isn’t quite as small as the Lange’s metalmark, but they’re still good candidates for captive rearing.  They live in very a very specific habitat type – shallow, seasonally pooled streams – and those habitats are becoming degraded in the areas in which they still live.  Rachel’s talk was about how the captive rearing program for the Hine’s emerald (of which she is a major part) works and demonstrated the successes of the program.  The goal of the program is to allow researchers to bring populations of Hine’s emeralds into the lab, rescuing them from areas where their habitat has been degraded to the point that they can no longer survive there, and keep them safe until those habitats are restored to survivable conditions.  If they do this, they allow the insects to survive periods of time when their habitats cannot support them.  In essence, the dragonflies become refugees in the lab!

The captive rearing program at the University of South Dakota began in 2003.  They originally collected nymphs in the field and brought them into the lab.  Once in the lab, each dragonfly is given its own container, is kept at the same temperatures they would experience in the stream, and fed bloodworms in the amounts they naturally eat at any given point in the year.  Basically, the team tried to mimic the field conditions as closely as possible.  The dragonflies might be fed once a week during the winter and several times a week during the summer because that is how much they would eat if left in the field.  When the nymphs are about to emerge as adults, they are transferred into emergence cages, allowed to emerge, and then released back into the field.  They don’t keep adults because there really isn’t a good way to keep dragonfly adults in captivity for long periods of time.

Recently, the group has also begun to rear dragonflies from the egg stage.  They collect eggs in the streams and bring them back to the lab, where the eggs are kept at the same temperature they would experience in the stream.  After they hatch, each nymph is placed in its own container and fed brine shrimp (sea monkeys!) daily.  Once they get bigger, they start eating the bloodworms, then emerge and are released as already described.

Rachel commented on the success of the program.  The program currently reports an 80-90% survival rate for nymphs, which is pretty good.  They have also placed some nymphs in cages (so they can’t be eaten) in their native streams so that they can compare the body size of individuals grown in the lab to those that would be found in the field.  If they produce nymphs that are too small or too big, they can cause problems, so they wanted to be sure that their dragonflies were about the same size as ones produced in the field.  Luckily, there is no difference between the body size of lab and field reared nymphs.  Rachel also stated that, although it took some time to make it work, the egg rearing part of the program is currently boasting a survival rate of 85%.  So, it looks like the captive rearing program is working!

Rachel ended her talk  by discussing the benefits of the captive rearing program.  First, it will augment the natural populations in areas where these dragonflies still exist, helping prevent extinction of the species.  Second, they are able to use the insects they rear in the lab to test efforts to repair habitat in streams where these dragonflies live.  By placing some lab reared nymphs in the stream and tracking their survival to adulthood, they can determine whether it is safe to reintroduce the dragonflies back into the area or not.  And last, the team has a large number of the dragonflies that can be made available for other researchers to study.  With endangered species, it’s generally impossible to do research in the field and it is illegal to remove them from their habitats.  The lab reared population that Rachel and her colleagues maintain will allow researchers to do experiments without harming the natural populations of the dragonflies.

Check back tomorrow for a report on Day 4, the next to last day of the meeting.  I’m going to a session on education in aquatic sciences, so I might report on one of those talks if they’re good.  Until tomorrow!

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Posts in this series:
Day 0 – Introduction to the Series
Day 1
– Invasive Crayfish
Day 2 – Giant Water Bug Dispersal
Day 3 – Dragonfly Captive Rearing
Day 4 – Integrating Service-Learning Programs into College Courses
Day 5 – Impact of a Small Preserve on Stream Health

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.

Notes from NABS Day 2

meeting logoEvidence for Overland Dispersal in a Flightless Aquatic Insect

Hello again from the NABS/ASLO 2010 meeting!  Today I’m focusing on Day 2 of the conference and my favorite talk of the day.  But first, two things I learned:

— Some aquatic insects are capable of moving a very long distance to get to new or better habitats.
— The person who designed the layout of the Tuesday poster session should be tarred and feathered for coming up with the absolute worst possible layout.  While I feel like my poster went over fairly well (I even had 2 judges tell me that it was very well done , giving me some miniscule glimmer of hope that I might win one of the tiny number of awards at NABS this year), it was a physically miserable experience.  The posters were arranged like this:

poster session

One of the two poster session rooms, the one my poster was in, before the poster session began.

The space was about 8 feet long and about 8 feet wide and each of these little alcoves held 6 posters each.  You could comfortably fit maybe 5 people in this space.  And THIS is what it looked like with 8 people:

poster session

The alcove in which my poster was located during the poster session.

I was forced to stand out in the aisle because I didn’t fit.  Wow that’s bad design!  Still, my scientific experience during the session was great once I got past the bad lighting, the inability of the AC unit to keep up (it was probably 85 or 90 degrees in the room – hotter than outside!), and the cramped quarters.  I got a lot of good feedback.  Considering this poster was the entire reason I came to the meeting, this is a good thing.

But back to my favorite talk of the day.  The title of my Day 2 favorite talk is at the top of the page and is probably easier to understand than yesterday’s if you’re not a scientist.  The talk was given by Kate Boersma, a Ph.D. student in Dr. Dave Lytle’s lab at Oregon State University.  The Lytle lab does some excellent research and Dave has been a star in the aquatics world since he was granted his professorship at OSU, so it’s no surprise that I liked Kate’s talk the best of the ones I heard today.  Plus, she’s a colleague of mine, a fellow giant water bug researcher, so you can’t go wrong.  She works on one of the same water bugs I study, the lovely Abedus herberti:

Abedus herberti mating

Abedus herberti mating.

Kate’s talk was about dispersal of this insect, or the movement from one habitat to another.  But before I get into the presentation, let me say a bit about dispersal in aquatic insects, especially as it pertains to insects in the arid (=dry) southwest.

Aquatic insects living in streams don’t really stay in one place.  They move around a lot, but there is a tendency for them to move downstream.  After all, simply losing your grip on whatever you’re holding onto in the water is enough to sweep you off into the current and far away from your home.  Invertebrates moving downstream by passive means (being swept along by the current), either intentionally or accidentally,  is called invertebrate drift.  Generally, moving downstream is something you want to avoid if you’re an aquatic insect.  Fish eat the insects and other organisms that make up the drift, so there is a high risk of predation for drifting insects.  Streams can also change a lot over their length, so it’s to an aquatic insect’s benefit to stay in the place that is best suited for it.  Insects CAN move upstream though.  They will crawl, or in some cases swim, upstream through the water.  Alternatively, many species with terrestrial adults are known to fly upstream to lay their eggs, thus ensuring that the population at the uppermost portions of a stream (the headwaters) remain stable.  Any movement of an organism from one area to another is called dispersal.

If an area becomes unsuitable for any reason, the insects need to move to another area if they are to survive.  This means dispersing.  This happens frequently in the arid southwest, but how insects move between habitats, the cues they use to signal that a move is necessary, and whether dispersal is limited strictly to up and downstream movements are still poorly understood.  Kate hopes to explain how Abedus herberti chooses to move to a new habitat, how far they can move, and in what direction.  And this brings us to the subject of her talk.

First she described the conditions in the area in which I also do my research.  We have a lot of streams, but many of them are dry most of the year (these are called ephemeral streams because they water only flows for a short time).  Even streams that flow most of the year can mostly dry out during the summer, leaving behind isolated pools of water into which the entire invertebrate population of the stream must go.  As these pools get smaller and smaller, it becomes stressful for the organisms living in them.  Abedus herberti is also flightless, so if the pool dris completely and they can’t find a new source of water, they die.  If they are able to instead move to another habitat nearby by crawling across the land, they might be able to avoid death and prevent the local extinction of populations within the area.  There is some genetic evidence that suggests this is possible, but Kate is the first person to really look into it.

Kate has been interested in which environmental conditions, which cues, prompt A. herberti to move from one habitat in search of a better one.  In her talk, she described a study she did recently.  She expected that pool drying would prompt a water bug to move from one habitat to another, so she set up an experiment.  She set up several opaque tubs filled with water that held smaller tubs inside them.  These inner tubs were assigned one of two treatments: either they were left dry or they were filled with water.  She then placed bugs inside the inner tubs, left them for a period of time (honestly, I didn’t get the time frame down, but it was something on the order of overnight or a week), and then compared the number of bugs that she found in the water-filled outer tubs in each treatment.  She discovered that more bugs moved from a dry tub to the wet outer tub than from a wet tub to the wet outer tub.  This suggests that the insects use pool drying as an excuse to leave the poor quality habitat in search of a better environment.

Kate also presented data on the distance that these bugs are able to move overland, though she did not collect the data herself.  Her labmates collected water bugs from several different pools, marked them, released them back into the pools, and then came back much later and recorded the location of the marked bugs they found.  They discovered that A. herberti prefers to stay in the same area, if not the same pool, in which they were found originally.  However, some had moved.  Of these, the females were found to have moved about 20 meters (just under 65 feet) while the males moved only 12 meters (about 39 feet).  The bugs clearly don’t move very far if they don’t have to.

However, Kate also showed a video that she happened to get through pure serendipity: a rather crispy looking male giant water bug who had left his aquatic habitat, had climbed into a dry streambed, and was hurrying downstream.  This was visual evidence that the bugs are able to move over land if conditions warrant the behavior.  She was also able to calculate a land speed for the bugs of about 4.6 meters (15 feet) per minute.  This is pretty fast for a one inch long animal!  She further calculated the maximum distance the bugs might be able to travel based on some data I had given her regarding they length of time the bugs can remain out of water.  Her calculations suggest that these bugs might be able to move as much as 6624 meters (4.12 miles) before they dry out and die!

So, Kate showed that overland dispersal can occur in Abedus herberti, that they use pool drying as a cue to disperse, and that while the bugs prefer to stay in one place, they occasionally travel across land for some distance in search of a better home.  Pretty neat, eh?  I thought so.  :)

Tune in tomorrow for another edition of Notes from NABS!

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Posts in this series:
Day 0 – Introduction to the Series
Day 1
– Invasive Crayfish
Day 2 – Giant Water Bug Dispersal
Day 3 – Dragonfly Captive Rearing
Day 4 – Integrating Service-Learning Programs into College Courses
Day 5 – Impact of a Small Preserve on Stream Health

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Unless otherwise stated, all text, images, and video are copyright © 2010 DragonflyWoman.wordpress.com.