Premature Retirement (For the Season)

Due to a rather terrible heat wave coupled with a somewhat extreme drought, I have decided to retire my tank prematurely. Initially I felt that I could keep it until late October, but my inability to go out sampling and my trouble keeping the tank at a reasonable temperature has lead me to the conclusion that I should take it down and try again either later in the season or next year.

Sorry to disappoint anyone, but I can't justify running a tank that continually heats up to the point that all my specimens die. An empty tank, is a sad tank.

I will try to find a new project, but for the time being I think I will enjoy what's left of my summer and you should too.

Exploring the Fatherless Nymphs of *Stenonema femoratum*

Perhaps one of the most often found mayflies on my sampling days are the Flathead Mayflies in the family Heptageniidae. This is one of the largest families with species living around the globe. Around my area though, there are about 100 species or so, and the most common ones I have caught are the species Stenonema femoratum.



A rather roughed up specimen missing a couple legs and part of a cerci.

These nymphs, like most of the Ephemeroptera I've collected, are scrapers that live on the bottoms of rocks and woody debris (which I recently acquired to make my tank more aesthetically pleasing). They are easily identified to family by their shovel-like flattened heads, and flattened bodies. All of these features allow the nymph to resist currents when on top of rocks, and to better cling to rocks when foraging fish flip them over in search of food.

Underside of the nymph.

Despite its humdrum lifestyle, this species exhibits a rather odd type of reproduction from time to time, tychoparthenogenesis. This is an infrequent bout of asexual reproduction in which a normally sexually reproducing female lays unfertilized eggs that hatch into nymphs. This occurs rarely and very few of these eggs actually become nymphs, and yet, this type of reproduction continues on, especially when water temperatures vary.

Hopefully I'll be able to go sampling in a few new locations since I'm seeing the same species over and over again at my two main sites.

Work Cited:

Ball, Shelley L. 2002. Population variation and ecological correlates of tychoparthenogenesis in the mayfly, Stenonema femoratum. Biological Journal of the Linnean Society 75:101-123.

A Damsel in Distress

The other day I was surprised to see one of my damselfly larva wandering about the tank during daylight hours. Normally, the only time I see them is when they crawl on the rocks late at night. Since it was so easy to see, I decided to ID this guy, which was quite easy.

You'll notice the fan-like projections at the end of its tail, these are actually its gills. These caudal gills are thick and triquetral in shape, most other damselfly larvae have thin, long caudal gills. It also has a thicker body compared to other damselflies. All of these characteristics indicate it is a member of the family Coenagrionidae and the genus Argia. I lack a key to bring it to species, but I also lack a scope to closely examine it.

These larvae are cold intolerant, and usually mature when the weather begins to warm up in order to take advantage of the summer months. Due to the fluctuations in temperature in the tank, I'm sure its juvenile hormone levels have been ebbing and flowing, both encouraging and deterring its maturation.

In my mind, I thought that perhaps it was hunting in preparation for the energy depleting molt leading to adulthood. I felt guilty that I hadn't sampled in awhile (the weather has been incredibly dry and hot) and as a result had few mayflies for it to hunt. So, I dug up a caddisfly and pushed it towards it in the hopes that it would feed.

Instead, it walked over the undulating caddisfly larva, and walked into the hole I created digging it up. It was frustrating to see this odd behavior. I was worried that perhaps something was seriously wrong with the pH or chemical levels in the tank.

My nervousness increased when I noticed the larva pawing at the corner of the tank, and swimming up the corner then floating down. Although it was capable of a burst of speed, it was unable to reach the water's surface.

I was compelled to push it toward the divider at the center of the tank, all the mayfly larvae had used it during their adult molts (most anyway), but I assumed it would prolong the molting until it felt air.

After taking a few more pictures, I left it alone in the hopes that it would climb the divider and emerge in the appropriate fashion.

I was disappointed when I returned to check on it after a few hours.

It had begun to molt still in the water, and probably drowned after a certain point. Due to this catastrophe, I decided to redesign the tank to create more "ladders" to the surface of the water.

I feel it's more fung shui now

I still have one damselfly larva left, I'm planning on doing better for this one whenever it decides to molt.

Making a Case for a Couple Trichoptera

Trichoptera (caddisfly) larva are amongst the most vital in the assessing of aquatic ecosystem health. They are usually the most sensitive to pesticides, and their vital role in the ecology of sports fish, such as trout, make them incredibly valuable to fishermen as well. They exhibit many different lifestyles and can be found in flowing streams, edges of lakes, and even stagnant wetland pools. Perhaps the easiest way of identifying them is by the cases that some of them build using silk and other materials, not unlike that of certain caterpillars (which they are closely related to), and their worm-like bodies with anal hooks at the end of their abdomen. To those new to identifying aquatic insects, they may simply look like worms, or even Dipterans (flies), but using some form of magnification, one would be able to see three legs on their thorax, which sets them apart from the legless Dipteran larva.

So far in my tank, I have two different families of Trichoptera: Leptoceridae and Hydropsychidae. These are two quite different groups of Trichoptera, and although I lack a dissecting scope (which I sorely miss at the moment) I believe I have a few identified down to genus.

Leptoceridae: Nectopsyche

Perhaps one of my favorite Trichoptera, these are commonly referred to as Long-Horned Case-Maker Caddisflies. They are typically found in cases made of fine grains with plant material attached to the outside. They also have extremely long back legs that typically have black on the joints. The first one I collected I could not stop taking pictures of, although none of them do it justice. I had to search elsewhere to find good enough pictures to show just how amazing these Trichoptera are.

B. The characteristically long antennae. C. One species without long antennae has a characteristic double line.

The genus Nectopsyche is omnivorous and have portable cases that allow them to roam looking for food. In fact, I believe these are the most mobile Trichoptera I have ever collected. Unfortunately, there is not much work done on this genus in North America, most of what I found concerned the Neotropical species that were recently discovered. They are quite common and there are at least 15 species found in North America.

Nectopsyche spp. with its case.

Hydropsychidae: Cheumatopsyche

Perhaps one of the largest families and one of the most common throughout North America. Like most Trichoptera, they use their silk to create cases, but instead of being portable, these cases are permanent retreats on the bottom of boulders. At the mouth of the cases, they spin nets to trap particles passed downstream by the current. When put out of these retreats, they will try to take one from another of the same species.

Again, not one of my pictures.

These are quite aggressive to conspecifics (same species). They are usually widely dispersed in streams unless there is a large amount of cobble for them to use to make retreats. During my research I've found this genus to be the most commonly used in assessment of streams due to their high sensitivity.

I'm hoping to go sampling either today or tomorrow, and will focus on finding species I do not already have.

Hacklegill Mayflies: A Closer Look

It seems every time I sample, I find quite a few of the same large tusked mayflies. I enjoy collecting them because of their size and somewhat intimidating looks, but when I bring them home, they invariably bury themselves in the gravel. After doing some research on them, I discovered the reasons behind their behavior.
These mayflies are in the Potamanthidae family, which are a group of Old World burrowing mayflies. There are only four species of this family in the U.S., and two are found in my state, Anthopotamus myops and A. verticis. The genus name has changed somewhat recently, which made my search slightly difficult, but according to Aquatic Insects of North America by Merrit, Cummins, and Berg, Anthopotamus is the currently accepted genus name. Now, this particular key only took me to genus, and I had to look at distribution maps to figure out which of the four species they could be, so there is some slight uncertainty as to what I have exactly.

I recovered this carcass after what I assume was a damselfly attach, it was missing most of its innards.

So, what are those needle-sharp looking tusks used for? Cleaning detritus from the setae on their forelegs. For such a nasty looking body part, they play such a subtle role in this animal's ecology. I speculated for a time, that this group of Ephemeroptera (mayflies), were in fact carnivores, which isn't common, but also isn't rare. In my research I found that they in fact, are detritivores. So they basically eat FPOM (fine particulate organic matter) that is either swept off of surfaces by the waving of their forelegs, or suspended in the water. One paper I read found that close to 90% of their diet was detritus with a few diatoms thrown in, with the diatoms simply being consumed becasue of their being on the wrong rock at the wrong time. This got me thinking, how in the world did these researchers look at the gut contents of such tiny creatures? I know the obvious answer, microscopes, but how were they certain of what they were looking at? It makes me appreciate the field of aquatic entomology even more.

After finding out what their tusks were used for, I researched their affinity for hiding in my gravel. I found that their prefered microhabitat were interstitial spaces in gravel and pebble-sized substrates (basically the "between" places). This perplexed me since my collecting methods are flipping over rocks and collecting what's underneath. I then found that they prefer shallow waters (<1m) in areas with low current velocities. This described the areas I found them in quite well, except that there were few gravelly areas, only silt deposits and larger rocks. Another paper noted that they commonly had negative phototactic responses, in other words, they avoided light. So in my mind, they inhabit the bottoms of these rocks due to their locations in the streams and their effectiveness at blocking light.

As for the name Hacklegill mayflies, this has to do with the long feathery gills found spreading laterally on their abdomen.

Papers on Anthopotamus:

Bae, Y. J., and McCafferty, W. P. 1994. Microhabitat of Anthopotamus verticis (Ephemeroptera: Potamanthidae). Hydrobiologia 288: 65-78.

Bartholomae, P. G. and Meier, P. G. 1977. Notes on the life history of Potamanthus myops in southeastern Michigan (Ephemeroptera: Potamanthidae). The Great Lakes Entomologist 10: 227-232.

McCafferty, W. P. and Bae, Y. J. 1992. Filter-feeding of the larvae of Anthopotamus (Ephemeroptera: Potamanthidae). Annals of Limnology 28: 27-34.

Finally, Some Fresh Air!

Thanks to a combination of cool weather and replacing my filter with a simple aerator, the tank has remained below the 80s (it was even near 65 F the other morning). I decided that now I could go collect some more insects for the tank without worrying about them boiling alive once I brought them home. My boyfriend was nice enough to tag along (which was a real surprise), and as a result, I believe he is willing to help me go to further locations to collect some rather unique specimens that are hard to find. (Yay! Possible road trips!).

Anyway, I have a few pics of emergence events that are better quality.

This is a subimago molt emerging from its larval skin. Unfortunatley I found him drowned.

I believe last time I called this a subimago, but I was mistaken, this is the final adult form.

The three dark spots between the obvious green eyes are possibly ocelli, which are light sensing organs.

You'll notice a lack of feeding structures, this is because adult mayflies exist for one reason, procreation.

The other evening, when I felt all hope was lost for the remaining insects in the tank, I found that a damselfly larva was out and on top of a rock. It was sitting on top of one of my caddisfly larva, which made me think it was trying to attack it, but it remained motionless until climbing to the bottom of the rock moments later. Although the pictures are blurry, I think the larva looks amazing with its white racing stripe going down its abdomen and the white X on its thorax.

Hopefully, the cool weather will hold up and I'll be able to bring more specimens back from different locations!

Tragedy Befalls the Tank

So far, everything has been going quite well for my little tank, that is, until the other night. It's been rather warm lately, but I usually keep a close eye on the temperature of the tank. Most aquatic insects have no problem with cold water, but water above 75 F can be deadly. Part of this is due to their inability to withstand the heat and the fact that oxygen becomes less soluble in warm water and thus oxygen levels will drop. It had been floating near 80 F for the past couple of nights, which created quite a few emergence events. This lulled me into a false sense of security, so on a night I was otherwise occupied, I assumed that everyone would be fine even if the tank heated up.

A tusked mayfly and its subimago stage (winged juvenile).

Subimago to the left and adult on the right.

I was quite wrong. I came upstairs to grab a few things and found that some of the mayflies were out from under their rocks, one in fact had lodged itself against my divider. I took several pictures then returned to the party downstairs, not realizing how odd that was.

Tusked mayfly.

When I turned in for the night (3am ish), I found all of my mayflies out on the rocks. Their gills, located along their abdomen, were flapping frantically. The temperature of the water was above 86 F. I did not think this directly related to their odd activity, in fact, I simply thought I was observing a new behavior due to it being to late in the evening. Why wouldn't aquatic larvae be nocturnal, most of their predators are diurnal anyway?
When I awoke the next day, all of the mayflies were dead. It was quite upsetting and made me realize that I must find a way to maintian the temperature of the tank in the 70's at the least. I figure that removing the lid and just having mosquito netting over the top will naturally allow more evaporation and thus removal of hot water from the system. If this does not work, I may have to research some type of tank equipment that would do the job.

An Emergence Event

Over the past couple of days I've continually gone out sampling. While out and about, I found a baby water snake and managed to catch it after a few tries. While handling it, I found a bulge in its side. I felt it and found it to be conicle and quite sharp at the end, and so I believe it might have eaten a snail...which is kind of strange.

Aside from my snake encounter, I managed to acquire quite a few specimens. I actually found one of my favorite kinds of Trichoptera (caddisfly larvae), it looks quite similar to a spider with long thin legs that were black at the joints.

I was so fascinated by this little guy that I couldn't stop taking pictures of him, and since he was one of the few who decided not to scurry under rocks the moment I placed him in the tank, he was quite photogenic.

Since the water was down I was more able to explore the river this time around, and found quite a few unique areas. A little hollow under a tree was the most promising, except I was suspect of there being a snapper hidden there. Most of the areas I found were full of crayfish, which usually isn't much of a problem, but they were so dense that every rock I picked up was hiding one or two.

Later in the evening, I found that one of my mayflies had molted and become an adult. Unfortunately, in my excitement, I opened the lid to the tank and it flew out before I could take a picture. I guess I know now that the mosquito net needs to be put in place.

It's Samplin' Time!

After a few stormy days, I found myself unable to go out sampling for insects due to high waters. This was kind of frustrating since I finally got the tank up and running. So, I decided to go sample something else...substrate for my tank! I needed what most scientists would call boulders (based on their size exceeding that of cobble), but most other people would simply call rocks. Specifically, I was looking for porous rocks that already had algae or a macrophyte (aquatic plant) growing on it. So I went a samplin' and found that the waters were so high that the type of rocks I was looking for were in far too deep of water for me to reach comfortably (I wasn't about to dive into chocolate-milk colored river water). Feeling defeated, I returned to the shore and was surprised to find something laying on the bank. A shed snake skin! I am unsure exactly what species it is from (I mean come on, it's only a skin), but I collected it and brought it home to measure since it appeared to be rather large.

A little over 3ft of snake skin.

Perhaps a Herper can help me ID this?

A couple days later I tried sampling again, this time at a location I had not been to before. My intent was to collect both rocks and insects, but I knew that the water was still far too high to get anything I was searching for.

I was in luck this time, though, because the water was just shallow enough for me to collect a few rocks. While I was inspecting a few for collection, I found insects attached. Most of them were quite small and I was unsure that they would survive time out of flowing water, but I collected them anyway.
After about a half hour out, I notices a chirping sound coming from the bank behind me. I looked over my shoulder and found an agitated fox squirrel eyeing me. It kept barking and chirping and would begin to approach me then scurry back to a branch. I decided that perhaps it was time for me to return home with my bounty, rather than risk whatever the squirrel had intended for me if I did not leave.

After returning home, I placed the rocks in my tank and then faced a minor dilemma. How would I put the insects into the tank? I didn't want to stress them any more by picking them up with tweezers (since I do not own forceps but will acquire them soon) then drop them into a turbulent tank (the filter was running). I also did not want to dump them and possibly crush them under the weight of the falling water. So I chose the middle ground and gently placed the container into the tank and let the water slowly rush in and sweep the insects out. I knew instantly that my mayfly larvae would not make it since it was promptly sucked into the filter (a problem I must correct for next time), but my caddisfly larvae appeared to survive, burrowing into the substrate for cover. After staring into the tank, much like Mojo did at the goldfish, I found a small egg case with a vermiform (wormy looking) larvae crawling out. I was surprised by this, but assume that it was previously attached to the rocks I collected and during introduction to the tank, was swept off. Assuming my caddisfly, which is in the family Hydropsychidae, was a scraper (algae eater), I threw in an algae flake and hoped for the best.

My tiny caddisfly larvae.

So, I now know that introductions will be done with the filter OFF, in order to prevent casualties, and that I seriously need forceps and a magnifying glass in order to see things more clearly.

Next time I plan on collecting some more rocks, and some larger, more active insects. Hopefully the river will go down enough for me to get out there!



Parasites and Pesticides: An Uncomfortable Truth

Yesterday, I found a rather odd tree frog on the side of our house. It appeared to have two sets of front limbs, which is quite rare and indicative of a potential parasite, the trematode.

See anything strange here?

Just for comparison...

I further investigated causes for deformed limbs in frogs and found an interesting article from Earth Observatory discussing Dr. Joseph Kiesecker's experiments on pesticide and parasite exposure to tadpoles (so, yes, this does fall into the category of aquatic ecology).

http://earthobservatory.nasa.gov/Newsroom/view.php?id=22544

From this article I learned that agricultural pesticides that are washed into aquatic systems (ag runoff) may negatively impact tadpole immune systems. The weakened tadpoles are thus more susceptible to infection from trematodes and are more likely to form cysts that may result in limb deformities. The scary part is, the concentration of pesticide necessary to initiate this effect is equal to or less than the acceptable amount present in drinking water, aka, if you live in an agricultural area you may be consuming these types of pesticides.

 So, how do these trematodes get to the tadpoles, and why do they cause these deformities? Well, the trematode utilizes several hosts in order to reach its definitive host, a wading bird. The infected frogs have deformities so that they are easier for these birds (herons for example), to catch and consume.

Trematode Life Cycle

So, I bet you're wondering just how precise these trematodes are at finding their hosts? Unfortunately, if you've ever had swimmer's itch, you've been infected by this trematode. Trust me, I got it a time or two while collecting snails, it's not the end of the world. If you were in a tropical system though, you might run the risk of getting Schistosomiasis, a potentially fatal infection that kills millions each year. And that's why I prefer waders to bare skin in stagnant waters.

Meet the New House Guest!

After about a week, I decided that enough chemicals had evaporated out of the tank for me to introduce an organism. Unfortunately, the only day I had enough time to get a goldfish from my mom's pond was one of the hottest days this season (upper 90's). This presented some problems, first off, my mom doesn't live that far away, but I have to take curvy back roads. This meant that on the way back I would need to drive slowly, thus making the hot car ride even longer and potentially stressing the fish out too much.

When I arrived, my mom asked if I would prefer to take some pond water or well water. I hadn't considered what type of water I would be taking the fish home in, so I was stumped. I didn't want to put pond water in my tank for fear of adding parasites, but I also didn't want to add well water because of the high levels of metal. In the end I took some pond water for the fish's sake and only added a little bit with him during introduction.

Speaking of introductions, my youngest cat, Mojo, has taken an interest in the fish, to the point that I was afraid to head to work that day. I was relieved to come home and find everyone where they should be.

Mojo checking out our house guest.

I'm planning on acquiring my divider tomorrow and should be getting some mosquito netting in the mail Tuesday. At this rate, I'll be able to get some plants and substrate and then finally insects!