Saturday, 23 April 2011

The Summer of the Reduviidae

A wheel bug from Costa Rica, preserved at the Museo de Insectos, University of Costa Rica, San José.
 
Let it be known that I am extremely excited for this summer.

I applied for a few internships, but those didn't work out. I was disappointed, of course, but other opportunities popped up, ensuring that I won't be idle during my time off from classes. I applied for a grant from my college, and received it. Thanks to that, I will spend six weeks during the summer carrying out a project I designed. This will involve me romping around the college's field station with my exploring hat, bug nets, and a bag full of bug collecting equipment, investigating the assassin bug diversity at the field station.

This is awesome for a number of reasons:
  1. I'll be investigating a question no one has yet researched
  2. I'll be acquainting myself even more with assassin bugs, a group of insects that is quickly becoming my favorite
  3. I will have ample time for exploration
  4. I'll find more than just assassin bugs
  5. With six weeks, I won't be rushed
  6. I'll have the opportunity to present my findings to the public, spreading my love of insects
  7. I'll be doing all of this on my own
It's a time to prove just how much I've learned so far, in addition to doing something outside of a class. I've done some insect collecting at the field station already, as part of a Zoology class, but our time was limited, resulting in me not having enough time to do all I wanted. This time around, I can be at the station essentially all day.

I can also tackle the project knowing what to look for and where to look, meaning that I should have a lot more success than I did during the class in finding assassin bugs.

Then, once I finish the project, I can use what I learn to inform how I carry out my capstone project, which will be an investigation into the life habits of the wheel bug, Arilus cristatus, again at the field station. I'll be doing that project for a grade, and it will be essentially the most important project I undertake during my undergraduate career.

So that's quite critical.

I've been doing a lot of research for the past few months, looking for general information about assassin bugs, insect collecting methods, and planning for the summer. In a few weeks, I'll be able to start the culmination of all that work.

I'm going to hit the ground running.

Another project I'll be doing this summer is an herbarium indexing project for the college. It will involve scanning pictures and data sheets into an online database that will catalog plant species from Ohio, an area I need to brush up on. Between that and my assassin bug projects, I feel as if the next few months will be full of productivity.

I plan to keep a field journal during my projects as well. I've kept a few in the past: when I was in the Southwest for a desert ecology class, and in a few places I've been in Costa Rica. I hope to make my summer one much more detailed, and in that vein, more useful. Not to mention the fact that it will make it a lot easier to remember my methods, where I find certain insects or habitats, etc. Speaking of which, I need to see about getting a giant map of the field station...

Assassin bug (Zelus sp., possibly Z. luridus) that has captured a fly

Monday, 11 April 2011

Colorful Katydids


Nothing in Biology is ever as simple as it seems. That’s the beauty of it, and this is especially true whenever insects enter the picture. Last June, I was scouting out my backyard for insects and other things, and came across a small, brightly-colored insect: vivid green and orange, it was almost neon. So what did I do? I snapped two pictures of it and moved on, not thinking much of it.

 Scudderia sp. on a leaf of Vitis sp.

Obviously I wasn’t thinking very well that day. Returning to the pictures a little while later, I started to investigate to figure out what exactly it was. Truthfully, when I first saw it, I thought it was an assassin bug nymph. Actually, it’s a nymph of a bush katydid, genus Scudderia. An easy way to identify a Scudderia nymph is from their white and black-banded antennae.

Unfortunately, that’s about as far as I’ve gotten with this particular nymph. According to Bugguide, there are eight species of Scudderia (in North America at least). Ohio has five of them:
  • S. curvicauda
  • S. furcata
  • S. fasciata
  • S. pistillata
  • S. texensis
 
 Master of the Grape Leaf

Right now I’m leaning towards Scudderia furcata, the fork-tailed bush katydid, but I can’t say for sure until I get my hands on an identification guide. S. furcata and S. cuneata look similar, and based on pictures I’ve seen, this one looks like one of those species. And since the latter is distributed in the southeastern United States, the one in my picture seems likely to be S. furcata.

At any rate, even if I don’t know which species it is, it’s still a beautiful specimen. It’s interesting how colorful some insects can be—and how bright they can be. The adult form isn’t anything to go crazy over: it’s usually a plain green color, though sometimes you find a pink morph, which is pretty darn neat. It’s kind of sad that the adults lose the vibrant colors the young have...maybe as they grow, they shed their rebellious phase and go mainstream. Probably better to avoid being eaten.

Thursday, 7 April 2011

Algal Symbiosis & More Solar-Powered Sea Slugs

I stumbled across a very interesting article the other day, via Wired. It elaborated upon a study on the spotted salamander (Ambystoma maculatum) and its relationship with algae. I hope you’ve got a good grip on your chair, because you’re liable to fall out of your seat otherwise. It’s pretty sweet news.

Algae is quite useful. It’s food for smaller organisms, and photosynthesizes, providing the rest of us with oxygen, which is a good thing. In the case of the spotted salamander, it’s an even more intimate relationship. The salamander lives with algae within its cells, which is the truly exciting news. Symbiosis between salamanders and algae isn’t anything new: it was even known in this salamander before the new study. But the crux of the matter is the degree of the symbiosis. Since the algae are within the salamander’s cells, that is a darn close relationship. In fact, such an intense relationship was previously thought to only occur between algae and invertebrates. This is the first time that it’s been shown between algae and a vertebrate, proving that creatures with backbones still have some tricks up their sleeves.

So how do the algae associate with the salamanders, and when?

The algae occur within the embryos of the salamanders, so the symbiosis starts early, literally in the womb. The scientists involved with the study think that algae get inside of the cells of the embryos via two routes: being passed down from the mother salamander (akin to a starter set of algae) and by obtaining the algae from the environment. So essentially, the salamanders have a small amount of algae to start them off, and then are able to obtain more from the vernal pools in which the egg masses are laid. An algal bloom is triggered inside the embryos (they’re not sure why this happens), and BOOM! Now the salamanders have a whole bunch of oxygen-producing algae. And that’s exactly why the algae are so important to the developing salamanders: oxygen. You know how some people say all you need is love? Well, oxygen’s important too.

If you’re a developing salamander embryo, just hanging out in your egg mass, you have a lot of support—about 100 other salamander brothers and sisters. To put this into perspective, here’s a picture of the egg mass:

Photo by Roger Hangarter, source: Live Science

Kind of cute, isn’t it? Sort of similar to a frog egg mass. So now that we know what the egg mass looks like, we can imagine the problem with it. When you have so many small salamander embryos packed in there, and you have the luck of being the embryo in the middle of the whole mass, you’re going to be starved for oxygen that’s being used up at the edges. But wait, there’s still hope! You have algae from your awesome mother salamander that are photosynthesizing, giving you free oxygen. All you have to give them is your nitrogenous wastes, which you didn’t want in the first place anyway. That’s the beauty of this symbiosis: both algae and salamander benefit, and on top of that, it’s recycling!

Thanks to the oxygen produced by the algae, the embryos are more likely to survive: developing in a healthy manner, and they’re bigger than salamanders that weren’t provided with oxygen from the algae. The embryo stage is when the algae seems to help the most, though the algal cells stick with the salamanders throughout the rest of their lives.

As befitting any other scientific study that’s in the least bit interesting, this one raises a lot more questions. Other salamanders have associations with algae, so where do they fall on the symbiotic spectrum? Are the associations as intimate as this one, where the algae are within the cells, or do the algae play a smaller role? Is more than one species of algae involved, and are different species better partners? And what about other amphibians? If salamanders have these relationships, what about other amphibians: frogs? Caecilians? It’s all very exciting.

Since we’re on the topic of algae symbiosis, this post is going to shift gears a bit and focus on sea slugs and nudibranchs. Besides, I have some cool pictures from Costa Rica I want to include here. Let’s get to it!

As I mentioned earlier, such an intimate algal symbiosis was known in the invertebrates already. In particular, some striking examples come from the Gastropods, especially sea slugs.

The sea slug Elysia chlorotica, found along the east coast of the United States, not only uses stolen chloroplasts from algae, but stolen genes as well. First, the sea slug seeks out some delicious algae. It has the chloroplasts that the slug needs, and to get them, the slug sucks them out of the algae—like it’s using a straw. This is called kleptoplasty, and this sea slug is able to take it even further. The slug has genes from the algae incorporated into its own genome. Again, it has genes from an alga in its own genome. This calls for a quotation.
“This could be a fusion of a plant and an animal — that’s just cool,” said invertebrate zoologist John Zardus of The Citadel in Charleston, S.C. - Wired.com
What does this fusion mean for the slug? Well, it’s now an autotroph, essentially. The genes allow the slug to produce a photosynthetic pigment, chlorophyll a, meaning that it’s able to photosynthesize: it’s solar-powered. Without the pigment, the slug wouldn’t be able to utilize photosynthesis, since the pigment is what allows it to use sunlight as part of the photosynthetic process. It absorbs a certin spectrum of light, and is actually just one of a variety of pigments. There are others, such as carotenoids, chlorophyll b, and xanthophylls, which all absorb a different spectrum of light.


Pigments other than chlorophyll a are called accessory pigments, because they absorb other wavelengths that chlorphyll a can’t use. Accessory pigments allow plants to take advantage of the entire spectrum of visible light.

So since the sea slug now has functional chloroplasts, and is producing chlorophyll a for said chloroplasts, it can produce its own food, and doesn’t have to feed anymore. All it needs is some sunlight, and it’s set for life.

A similar sea slug that I’ve had a personal encounter with is Elysia diomedia, which is in the same genus as the previously mentioned sea slug, but is found in the Pacific Ocean, off the coast of Central America.


This little guy is quite pretty: it has a brilliant green body, white and black stripes along its sides and head, and an orange and black folded parapodial edge (or if you prefer, lettuce).


They’re found in warm tide pools that get a lot of sun. Since it’s a species that is kleptoplastic, that’s a no-brainer.

 
It’s not the fastest creature you’ll come across, it’s content to move around with no hurry. It can stretch its body out pretty far, as I found out after watching it move through its tide pool. It’s sort of like a slinky in that respect.


In this picture, you can see some bright blue specks in the middle of its lettuce ruffles: that’s where it keeps the chloroplasts: way cool.

If you’ve only thought of algae as disgusting pond scum that you have to deal with when walking through a wetland, you’re mistaken. And you obviously are not a sea slug or salamander, having that attitude.

 
References:
http://dwb4.unl.edu/chem/chem869p/chem869plinks/gened.emc.maricopa.edu/bio/bio181/biobk/biobookps.html