Odonata

The Dragonfly Society of the Americas is an organization that was founded in 1988 by a group of Odonata (dragonfly) specialists, and has since grown into an organized group whose collective goal is to advance the "discovery, conservation, and knowledge of Odonata through observation, collection, research, publication, and education" (Mission statement). They host an annual meeting to exchange news and ideas, collect new samples, and attract new members, and this year was the 25th anniversary meeting of the organization's foundation. Myself and a good friend--April Brooks--had the privilege of attending this year, courtesy of our friend, Margy Balwierz, who contacted me about the trip through my science teacher. I'm a bug lover, so of course I signed on, and April kind of had no choice because I dragged her along. 

The meeting this year was split into three parts--a pre-meeting in Fall Creek, WI, a main meeting in Ladysmith, and a post-meeting (which we did not attend) in Vilas County. The meeting was headed by a group of ten or so experts, along with twenty-ish more mid-level experts, and a handful of people (like myself) who had no clue what was going on. The meeting was a mixture of informational presentations and field outings, and even if you actively tried not to, it was pretty much impossible to walk away without learning something. 

As a novice, most of the presentations that these people gave were way beyond me. Talks on Sympetrum corruptum and the distribution of gomphids rapidly progressed beyond my meager grasp of Odonata terminology, and looking back at the doodles in my notebook, I would say that I eventually gave up trying to understand what was going on. There was one, however, that I understood and picked up a few things from.

Ami Thompson gave a talk on the basics of dragonfly identification. For the experts (which as I mentioned comprised the vast majority of the people there), it was just that--the basics. For me, though, it all but blew my mind. 

There were six families of dragonfly that we were expecting to see over the course of that trip: clubtails, spiketails, cruisers, darners, emeralds, and skimmers. I'm not even going to try defining the damselflies, because with juvenile and gender differences being taken into account, there was no telling what you were looking at unless you consulted one of the experts. To me, they were colorful twigs with wings. 

Damselflies notwithstanding, Ami taught us some tricks that would let us differentiate between families.

Clubtail

Clubtail

Clubtails (Gomphidae), in my opinion, are the easiest to distinguish. They do, as the name suggests, have the characteristic bulge or "club" at the tip of their tail, but some species show this less than others and it's an unreliable defining point. We instead looked at the head (And no--I took no creative liberties when drawing that. Also, yes, they are indeed of this world). The eyes on a clubtail do not touch at all at the crown of the head, which is distinct from all of the other families. They also tend to have thicker thoraxes and long, skinny abdomens. 

Darner

Darners (Aeshnidae), by contrast, have eyes that meet together at the top and press together so tightly that it looks like "two balloons being squished together" (Ami), forming a line down the center of the face. They're a bigger dragonfly in general, with long tails and huskier thoraxes. 

Spiketail

Spiketails (Cordulegastridae) are also defined by their eyes, and lie in that middling area halfway between darners and clubtails. Their eyes touch at a single tiny point, forming a figure-eight pattern on the top of the head. Unfortunately, the eyes alone can be difficult to distinguish from skimmers, emeralds, or cruisers, so you have to look at the body shape--long and slender and usually marked by bands along the thorax--to get a better idea. 

Cruiser--thorax stripe detail

The cruiser family (Macromiidae) is most identifiable by the single yellow stripe that runs across either side of one's thorax. It's hard to mistake, and they're generally a longish, slender dragonfly with long, clear wings. They're long of leg as well, to better catch their prey. 

American Emerald

Emeralds (Corduliidae), unfortunately, are one of the harder families to distinguish. They can be longish or shortish; fattish or thinnish, and the characteristic, vivid, emerald-green eyes from whence they derive their name does not always occur. Most times there is a white or yellow ring around the abdomen at the base of the wings, but even that isn't always evident, especially in baskettails. 

Twelve-spotted skimmer

Last but certainly not least are the skimmers (Libellulidae)--the family you eventually turn to after going down the line of distinguishing traits and saying "nope" to all of them. Skimmers tend to be shorter than the others, with broader wings and a broader back wing set than the front. Colors and patterns range all over, but they're fairly common and pretty easy to catch. Chances are, if they're all over the place, they're skimmers. 

With this knowledge of general family placement, we headed out into the field. Dragonflies, we found, tend not to live in convenient places. They like water and plant cover, so you'll find yourself tramping through burdock, nettles, and brambles and then topping your boots in bogs and rivers in your search for these buzzing dots of greased lightning. I was stupid the first day and wore shorts, and so my legs accumulated a lovely pattern of criss-crossing scratches dotted with red mosquito bites (where there's mosquitoes, there's dragonflies, and subsequently there's Odonatists). The clubtails, cruisers, and some skimmers we mostly found on rivers and fast-moving water. The white-faced skimmers and emeralds seemed to like the bogs. Both sites made for adventurous walking, as you were either fighting for your balance against a current and slippery rocks or fighting for your balance against black, sucking mud that's trying to pull you down amongst all the other lost Odonatist skeletons that are no doubt down there.

Anyway.

Identifying--once you get the general family and are flipping through whatever guide you happen to have (I like Kurt Mead's Dragonflies of the North Woods)--goes something like this:

*flip-flip-flip*

"That looks right."

"It does. Maybe that's it."

*flip*

"Oh. So does that."

*backwards flip*

"What's the difference?"

"Better read."

*sigh*

"...'The Ashy clubtails' claspers do not have the downward-pointing tooth of the Dusky...'"

*pulls out hand lens and peers intently at dragonfly's rear-end*

"I think there's a hook."

"Let me look."

*follows suit*

"I don't think there is."

"We'd better ask Bob..."

Bob DuBois

Bob DuBois, among many of the other experts whom we pestered mercilessly, deserves our gratitude. As the writer of  Damselflies of the North Woods, he is not only an expert in all things Odonata, but also a patient teacher and a shameless nerd. Getting to know him, along with a scattering of the other experts--Ken Tennesson, Kurt Mead, Marley Garrison, and Bryan Pfeiffer--was a rare treat. Among other things, we learned from them how to differentiate adult from teneral (juvenile) dragonflies, and how to tell male from female; Tenerals are really easy to pick out, we found, even without capturing them. Their wings are brand-new at that point, and they're subsequently much shinier and tend to glitter brightly as they buzz by. To tell gender, you do have to catch them, so that you can look at the spot on the underside of the dragonfly where the abdomen and the thorax meet. Females are smooth down there, but males have an opening with bumpy claspers for gripping the female's ovipositor. In addition, he also has a big pair of claspers at the tip of his tail, which he uses to clamp onto the back of the female's head (often breaking through her exoskeleton and leaving a pair of holes). Their ritual is referred to as being "in tandem", and it looks something like this:

"In tandem" mating pair

Having the experts point us in the right direction was nice, and gave us something to work off. In the end, though, we took a day to ourselves on the river encircling our campsite, and spent the day catching and I.D-ing on our own. We got wet, messed up more than once, and yet in the end, it beat going to a mall or playing video games any day. 

If you're a bug person, or just some nerd who's willing to tramp through bogs, river, and heavy vegetation for the sake of proving you can, I would highly recommend this as a field trip. Next year's meeting will be held in Pennsylvania towards the end of June, and the group is always looking for new, younger members (it's an older-generation group--April and I were the young'uns the entire trip). You can tag along for free, or sign up for twenty bucks to be an official member of the society (with the added benefit of a catered dinner). 

As always to my readers, I hope you enjoyed wasting your time with this, and happy summer!

S.R.Koch

Our delicious stew

 Top: Frosted whiteface
Bottom left: Hudsonian whiteface; Bottom right: Dot-tailed whiteface;

April and Dominick

Left: Dusky clubtail; Right; Springtime darner

Dot-tailed whiteface female

Slugs

As promised--the enigma of the slug. As you probably know, this post was started in Seattle, when myself and the other NOSB-ers first stumbled across a three-inch long slug trying to cross a path at the Nisqually wildlife refuge. As is the nature of nerd-kind, we stopped to look, named him Matt, and fell to wondering why there was a gaping hole in his side that looked as if it had been pecked there by a bird.
Now we find out.
As is always best, I've found, I've decided to start with some background on the slug. For starters, they hail from the taxonomic phylum Mollusca, which includes a lot of the "weirder" species of earth such as cuttlefish and oysters. It's an old group of animals; we suspect they first became a distinct group around the Precambrian (600 to 4600 million years ago), and they have since built and diversified to a rough estimate of 200,000 described species. Slugs, specifically, are of the class Gastropoda, which translates to "stomach foot" in Latin. The name was earned in reference to the slug's apparent tendency to crawl around on its belly. In light of that, the muscular underside that they use for locomotion has been dubbed the "foot". Looking closely, one will note that a slug moves itself along by rippling the muscles along its underside in a wavelike pattern, lubricating its way with the famed snail slime (a stress-fracture fluid much like soap). The slime also serves as protection against drying out and sharp obstacles, and works so well that a slug could crawl over a razor blade without harming itself.

European black slug (Matt)

On the Seattle Adventure, we encountered three distinct species of slug. I am not the best at identifying gastropods, so the conclusions herein are hesitant; Matt and the other blackish-brown specimens that we encountered mostly in Nisqually were European black slugs (Arion ater) from the subfamily Arionidae. The reddish-tan ones were also from Arionidae (I could not pinpoint the species), and the leopard-spotted one from the rainforest was a banana slug (Ariolimax columbianus) from the subfamily Ariolimacinae. We noticed and wondered about on each of them the little hole that you'll note on the photo of the tan Arioninae specimen; they all had one, and they were capable of closing it and opening it like a sphincter. Research reveals it to be a "respiratory pore". Like our trachea, its purpose is to bring oxygen in from the environment, and it leads directly to the slug's single lung. In addition, the slug can absorb oxygen directly from the atmosphere, sucking it in through its porous skin and redistributing it throughout the body. Most of the organs are located on the dorsal side of the body to better allow the animal to crawl.

Unidentified Subfamily Arionidae

Now, as boneless, exoskeleton-less, shell-less animals with a record speed of around .013 m/s, one would pretty much suspect to see all slugs at the bottom of the faunal food chain. For the most part, that's true; slugs serve as the garbage disposal system of nature, breaking down dead plant and animal matter and recycling it back into the soil. They use their rasp-like "radula"--a ridged tongue that moves like a conveyor belt around a base of cartilage--to rasp away food particles and move it backwards down the gullet. They are hunted in turn by anything from birds to frogs, and for the most part eat at the bottom of the food chain.

Banana slug

There are exceptions to the rule, of course. Poiretia cornea, or the dalmatian slug, is carnivorous and, moreover, cannibalistic. It hunts other, smaller gastropods (specifically snails), chasing them down and then using the acids secreting in its slime to dissolve the shells of its prey. Some carnivorous species, such as the wolf snail (Euglandia rosea), have made a pest of themselves. The wolf snails were introduced to the French Polynesian islands to control a different species: the giant African land snails. Predictably, this did not work, and the wolf snails instead set about eating the smaller, native species and driving most of them extinct.
To finish off the post, I'll regale my readers with what I deem the weirdest of all slug traits: reproduction. Being slow creatures, slugs tend not to encounter others of their own kind as much as they'd like. To account for this, they've developed an adaption strategy shared by many deep-sea fish who share the same problem: duo-gender individuals. Being "hermaphrodites" like this allows any two snails to mate, and makes it much easier for them to pass on genes. The "ninja" slug (Ibycus rachelae), which was first described in 2008 in Borneo, has adopted and even wilder reproductive strategy. Rather than allowing its mate to come to close quarters, it instead fires a harpoon-like "love dart" in order to pass on its sperm. Weird as that sounds, it's very effective.
My thanks for your attention, readers. I hope you found this interesting, if not entirely applicable elsewhere in life. I will be leaving again this week for the Odonata Society annual dragonfly hunt in Fall Creek and Ladysmith, Wisconsin, and so I should be posting  about my adventures there in a couple weeks.
Enjoy your summer, and as always, happy reading.