Tuesday, November 27, 2012

More Caterpillar Parasitoidism

I'm finding interesting insects as I go back through my collection vials and inserting the final labels. The vials include a bunch of organisms I've collected over the years, and one in particular I just processed brought back some memories.

This is a pretty caterpillar called Leucostigma orgyia, more commonly known as the white-marked tussock moth. I picked it off a tree during the summer of 2010 and took it home to raise into a beautiful moth, as this was around the time my interest in insects was really starting to increase.

Things didn't quite go as planned.

My caterpillar friend had been parasitized! As I came to learn later, this is a pretty common occurrence, but this was the first time I had witnessed it. I cover parasitoidism in this post, but the short version is that a small wasp (in the family Braconidae) had found this caterpillar and injected some eggs into it, which later hatched and found on the insides of the caterpillar. Once the wasp larvae had their fill, they burst out of the caterpillar's body, as you can see in the above picture.

The larvae then spin their cocoons on the caterpillar's body (the caterpillar is alive for part of this process), and after a few weeks, they emerge as adults and fly away. It can be gruesome to watch, especially considering how many wasps emerged: more than 50 in this case.

The above picture shows one of the adult males, magnified under a microscope. In their normal life cycle, they would fly off in search of females to mate with to restart the cycle anew. A bit violent, but it's a great population control mechanism.

Saturday, November 24, 2012

Mushroom & Millipede Hunting

Yesterday was a nice day outside, and I figured it would probably be one of the last before the snow started falling. I decided to take advantage of this, and set off to find some mushrooms. (Also, it was snowing when I woke up this morning, so I was correct in my assumption. Maybe I should take up weather forecasting.)

I packed some collecting supplies and set off for the nature trail near my old elementary school. It has a nice array of habitat types and gratuitous amounts of decaying logs, so I was optimistic that I would find some nice mushrooms. However, almost immediately after I stepped onto the trail, my trip turned into millipede hunting. It's just too difficult to resist turning over every decaying log I find in hopes of getting some millipedes out of it.

My habit ended up paying off: I found many millipedes and collected 7 specimens from 4 separate species. It's astounding how many little critters live in decaying wood and the surrounding leaf litter. It's a miniature rain forest in there, but is often overlooked. It's really quite easy to collect arthropods using leaf litter: take a few fistfuls of leaf litter and maybe a little dirt, stuff it into a plastic bag, and later transfer it into a funnel. Put a light bulb above the funnel and a jar with some alcohol underneath the funnel, and give it a few days. All the arthropods will dig down through the leaves and fall into the jar. Put your catch underneath the microscope and you'll see all kinds of spiders, pseudoscorpions, harvestmen, millipedes, insects, mites, and so much more.

Though my excursion focused on millipedes, I did eventually incorporate fungi as well.

Another mysterious fungus, along with a millipede.

I rooted through the leaf litter near a dead log and turned over this old piece of bark. The fungus caught my eye long enough to distract me from the millipede (which I did catch later). It reminded me of another fungus I saw a few summers ago and blogged about here. I'm still at a loss for what they could be and need to find a good resource on fungi to research it more. I poked one of the drops and it ran onto the wood, into which it was readily absorbed.

The millipede ran surprisingly quickly, as they're usually slow. It didn't try to curl into a spiral when I picked it up, but rather thrashed around a bit instead. This is atypical for millipedes, which was intriguing. I think it's a Chordeumatid in the genus Cleidona, but I'll need to get it under a microscope and look at a few features before I can be sure.

The other millipedes I found were much more millipede-like in their habits. The most abundant millipede I found was a Polydesmid that I've found a few other times, but have yet to identify. 

Crawling around its new home, a nice plastic container I prepared.

It looks similar to another millipede I've seen before, Pseudopolydesmus serratus, though it doesn't fluoresce under UV light. I grabbed three specimens, and one is a male, so I should be able to figure it out.

After turning over enough decaying logs, I've learned which millipedes I can expect to see more often than not. And like usual, the beautiful Euryurus leachii, showed up under the logs I looked at.

This millipede is a little over an inch long and is easy to recognize. It has a blunt epiproct (its "tail"), separating it from other Polydesmids. The orange spots along its back and at the edges of its paranota, combined with the purplish hue of its body, readily identify this native millipede. It's certainly in the running for most beautiful millipede in Ohio. Once you cross into the central US, however, be careful: Auturus evides is a lookalike. I haven't seen a specimen of A. evides for myself, so I'm not yet sure how to differentiate them.

Another reason for E. leachii's beauty: its fluorescence under UV light.

Not to be outdone by all these amazing millipedes, the fungi made a comeback somewhere around the Soggy Bottom Trail.

It's usually much soggier. 

Decaying wood isn't only for millipedes, it's also great habitat for moss and mushrooms!

Those little brown mushrooms made a cute little home in a hole in the log, flanked by moss. If you look closely at the stalks coming up from the moss, you can see the calyptra (the green sheath) around the spore capsule. Think of the calyptra as a protective blanket keeping the capsule safe until it's time to let the spores go. If you look in the background, you'll also see a polypore coming out of the log...

The Soggy Bottom Trail did not disappoint!

Saturday, November 17, 2012

Neglected Collections

After my college graduation last May, I've been using my free time to go back through the bug collections I did while still an undergraduate. I had a lot of material left over--both dry specimens and ethanol specimens, along with photographs and lists to organize. I never quite had the time to do it while taking classes (or at least, that's what I tell myself), so I'm very glad I can take care of it now.

I've had this blog post about respecting your specimens gnawing at me since I read it during the summer, and felt a bit guilty. I had some pretty crappy labels with my specimens, or even worse, no labels at all! For some, I could remember exactly where I was standing when I collected them, so it wasn't a huge problem. But for others...well, those just had to be thrown out as useless.

Some of my specimens were new to the collection and represented unique information, so I wanted to make sure they were properly labeled and taken care of. With that mission in mind, I've devoted myself over the past month to slogging through my material that's been languishing for months (in a few cases, years). And now, I'm beginning to see results!

This box only has six empty spots now.

I've prepared labels for 90 specimens and put many of them under the microscope to identify them as close to species level as I could. This was difficult for a number of them, especially the centipedes, due to lack of practice by me and the lack of recent references, but it's been a fun challenge. I've also found some interesting animals (such as the centipede Theatops, the subject of my previous blog post) and experienced some great memories. Most of my millipedes were collected for a Field Techniques class with the help of two good friends, who spent their evening sampling through leaf litter with me. A scorpion was collected during a summer class in the New Mexican desert, where I learned about arthropod UV fluorescence for the first time.

Now I'm at the point where I can do something with all my collected specimens. Some of what I'm working on includes:
  • A guide to Ohio centipedes, which will be accessible online and will have pictures of certain identification characteristics to make up for the paucity of reference material online.
  • A publication of my assassin bug research
  • A publication/guide of local millipede species
It's exciting to put together what I've been working on for the past few years, and to find new projects. I'm hopeful that what I'm doing will be useful for others interested in these groups in Ohio. There definitely hasn't been much done with centipedes and millipedes, which is a barrier to anyone wanting to learn more about them or do their own research, so maybe this can be a springboard for future studies.

My to-do list: keeping me going. That "hola" has been there for a while, so I couldn't bring myself to erase it.

Sunday, November 11, 2012

Entomological Smackdown

"Yet the law of priority compels its adoption, and one's regret is perhaps to a certain extent lessened by the satisfaction derived from abolishing a name so ill-formed and so ill-sounding as Opisthemega." -R.I. Pocock
The above is taken from a manuscript clearing up confusion about the genus Theatops, which includes a few large centipedes with surprisingly fat terminal legs.

It's burying into the ground here, with the terminal legs trailing at the top of the picture. Yes, it can pinch with them.

There are many hidden gems like these in scientific publications, and it's always a joy to come across them. You're reminded that the entomologists writing them are people too. And I must agree, Opisthemega is a terrible name.

Pocock RI. 1888. Annals And Magazine of Natural History. 1:283-290. Link.

Friday, November 2, 2012

Science Video Friday - I Lichen This Post

The wonderful Field Museum in Chicago featured this video about Steve Leavitt and his lichen research, which hit my soft spot for these organisms.

Thursday, November 1, 2012

Marvelous Mossy Millipedes

I learned a new word recently: epizoic. It's related to epiphytic, which describes the relationship of plants that grow on top of other plants (think of bromeliads or lichens that grow on trees). While epiphytic plants have a house, epizoic plants have a mobile home---they grow on top of animals.

And what do some mosses use as a mobile home? Millipedes! In a paper published in December 2011, S. Daniela Martínez T. et al. describe this relationship between 10 species of mosses and a tropical millipede, Psammodesmus bryophorus.

Obviously this millipede is at the cutting edge of fashion.

Field work for this study was done at the Reserva Natural Río Nambi in Colombia. As the scientists sorted the 124 millipedes they collected, they noticed that some of their P. bryophorus specimens looked a bit green...because they had moss growing on their backs. (Sadly, the paper doesn't indicate whether or not the mosses caused any uncomfortable itching.)

Intrigued, they set to work and checked the 20 P. bryophorus millipedes they collected and found that 15 of them had mossy backs. One enterprising male was conducting a party train--he had 55 individual moss plants on his back. For a closer look at how the mosses grow, check out the next photo.

Figure 2 from S. Daniela Martínez T. et al. 2011.

The authors provide a guess as to why the mosses choose this species as land to build upon: it provides a stable surface. Better to build your house on a rock than decomposing leaf litter, eh? The mosses may provide an advantage for the millipede as well: P. bryophorus has a few racing stripes down its back, and the mosses cover those up, providing camouflage. These working hypotheses will have to be tested further, of course, but they're plausible.

A final fun fact? Spores from these mosses can fall off the millipede and grow into new plants elsewhere. Imagine that, a millipede imitating Johnny Appleseed. Maybe it should be named Mildred Mossspore.

I recommend reading the article itself for more information. You can view/download it for free here.

Martínez-Torres SD, Flórez Daza ÁE, Linares-Castillo EL. (2011). Meeting between kingdoms: discovery of a close association between Diplopoda and Bryophyta in a transitional Andean-Pacifc forest in Colombia. In: Mesibov R, Short M (Eds) Proceedings of the 15th International Congress of Myriapodology, 18–22 July 2011, Brisbane, Australia. International Journal of Myriapodology 6: 29–36. doi: 10.3897/ijm.6.2187