Category Archives: Arizona Lep Course

Bagworm

Bagworm… what an unfortunate common name. Then again, the bagworm caterpillar is not what most people would consider beautiful. But hey, decide for yourself!

Bagworms are caterpillars in the family Psychidae. They create elaborate cases to protect themselves, while leaving their walking legs free to travel and feed effectively. Case construction varies depending on available materials and their host plant, and the pieces are held together with silk produced by the caterpillar. They can retract into the case when threatened… this particular caterpillar was not very shy, though.

Since we were sacrificing some caterpillars for our research in Arizona, I decided to open up a bagworm case to see how the rest of caterpillar looked.

How strange! What wonderful construction of the interior of the case, and what a silly looking body. I have seen some smaller bagworm species in the North East (usually not more than a cm long), but they grow them big in the South West.

Just because it’s cute

Crotalus scutulatus – Mojave rattlesnake.
Adorable little rattler found on the road in Arizona. We carefully persuaded it to slither into the grass so it wouldn’t get run over.

At the light

Entomologists use a variety of techniques to capture insects. The most well known are butterfly nets, which can be used to scoop up just about anything that moves. Nets can be made with thin mesh, thick mesh, super long poles, baited with pheromone lures, you name it. And then there are pan traps, burlese funnels, malaise traps, sticky traps, bait traps… a nearly endless array of creativity. And one of the best ways to collect insects at night is to let them come to you.

It isn’t fully known why so many insects are attracted to lights, but they are. It may interfere with their navigational systems, and once they’re on the sheet they think it’s day time (so they default to their day time resting behaviors).

Many techniques fall under the umbrella term of “black-lighting”, even if you don’t use an actual black-light. They work quite well (even the ones you find in a party store), but even more powerful are mercury vapor lights (and much more expensive). A light, or combination of lights, are hung in front of a large white sheet, and… that’s it. The waiting begins. The set-up can be elaborate with frames and multiple lights, or as simple as a sheet thrown over a branch with a party light. I personally hang a small black-light from the outdoor light on my back patio, and clothes-pinned a sheet to the siding.

At the research station in Arizona (where the above photo was taken), we had several different black-lighting setups throughout the grounds. Some were closer to the stream, some by the buildings, and some were farther out in the woods. We also traveled to different locations in the forest and the desert and set up black-lights there.

Only certain species are attracted to the lights, and they come at different times of night. Sometimes only one sex comes in, meaning the other sex is virtually unknown or uncommon in collections. And the timing means that you might have to stay up until 3am to get the species you’re looking for. If you’re lucky, it will cooperate and come in before midnight!

What you need to collect insects at night

  • Black-light or mercury vapor light, and a power source. This could be an outlet if you’re near a building, a battery, or a generator. Make sure the light you buy is compatible with your power source!
  • A white sheet. Anything with patterns or colors will make it difficult to spot insects.
  • Ropes and clothes pins. These all depend on where you want to hang your sheet.
  • Collecting jar. If you want to keep things alive for observation, any container will do. If you want to kill your specimens, use a cyanide kill jar or a plaster jar charged with ethyl acetate (you can also put a jar of insects in the freezer). Keeping a bit of tissue or paper in the container will prevent the insects from running around.
  • Headlamp or flashlight. You’re outside at night, after all.

Some tips

  • Hang the light away from the sheet. A few inches to a foot away is ideal. This prevents your sheet from overheating and allows for more reflection on the sheet.
  • Keep the sheet steady against the wind. Hold down the bottom with rocks, and generally stay out of windy areas.
  • Many types of equipment can be bought through BioQuip. If you’re looking for cheaper materials, try Amazon.
  • Only collect where it’s legal. Ask for permission to use land, and get collecting permits when needed.
  • Consider the time of year. Things are winding down here in the North East, but you need to figure out when your target species will be out and about.
  • Be patient! It’s good to go black-lighting with friends (and maybe alcoholic beverages).

A cute little mantisfly on a sheet in Arizona.

Caterpillar hunting

If you’re going to hunt for caterpillars, it helps to have extra pairs of eyes (and extra beating sheets). Here was the Lep Course in Arizona, looking for anything we could get our hands on. We stopped on the side of the road, unloaded out of the half-dozen or so vehicles it took to carry us all, and started hiking. We actually didn’t find many caterpillars that day, but it was lots of fun looking (and beating the ocotillo with sticks).

The view. Not bad.

Mate guarding

It’s sort of like how human couples hold hands. Except tiger beetles hold on with their jaws.

Cicindela sedecimpunctata – Western Red-bellied Tiger Beetle.

Caterpillars of the desert

Here are some beautiful creatures we encountered while exploring the shrubby desert not far from the mountains in Arizona.

Limenitis arthemis – the Red Spotted Purple (family Nymphalidae). Not exactly a glamorous caterpillar, considering how beautiful the butterfly is! But also consider how useful this camouflage strategy is. Looking like an unappetizing pile of bird poop with fungus growing out of it doesn’t exactly scream “dinner”, now does it?

Hyles lineata – The White Lined Sphinx (family Sphingidae). These guys were everywhere! They were huge, wandering around looking for places to dig into the ground and pupate.

Sphingicampa hubbardi – Hubbard’s Silk Moth (family Saturniidae). WOW!!! This is one of my favorite caterpillars of all time! What is difficult to discern from this photo is just how shiny those silvery spikes are. You can nearly see your reflection in them! This caterpillar is about 2.5″ long, so you would think it’s easy to spot. In fact, all those silvery spikes and brightly colored spots help the caterpillar blend in to its brambly and colorful environment. The adults are fuzzy with pretty pink underwings, but I think the larval stage is the most impressive.

A visitor to the research station

Our first night at the SWRS, we all took our killing jars to the sheets to catch some moths. In the woods surrounding the station (and even right on the porch!) they had sheets hung up with black lights and mercury vapor lights set to attract insects.

We were giddy with excitement, trying to identify moths, all trying to grab the prettiest or most unusual ones. Late into the night, we sat in the lab pinning our fresh catch, occasionally venturing out with headlamps to gather more.

Sometime far past my bedtime (will someone please remind me why I, as a morning person, chose to study moths?), one of the students nonchalantly entered the lab and said “Hey, anybody want to see a snake? Anyone? A snake?”

This is who had slithered right up to the building.

This is the black-tail rattlesnake, Crotalus molossus. What a beauty! I had never seen this species before. Two years ago I did find a shed skin of a black-tail (I was able to identify it by the scale pattern on the head) but that’s it. So it was pretty neat to add another reptile to my life-list.

Once everyone had taken photos, we realized we needed to find a way to move a venomous animal away from the laboratory. No one had a snake hook on hand, so we used the next best thing. A butterfly net.

Hey, it worked! The cute little snake was moved safely away, and we all went back to work.

Unfortunately, I only saw one more snake during the trip. Didn’t have much time for road-driving for herps… that will be on the agenda next time for sure.

The Southwestern Research Station

So now, to formally introduce the lep course.

I spent a bit over a week at the Southwestern Research Station (SWRS) in Portal, Arizona this August. The station is run by the American Museum of Natural History. I was participating in the Lepidoptera Course, studying moths and butterflies and caterpillars with some of the best researchers in the field. It was an amazing opportunity, and I learned so much!

The SWRS also offers courses in Herpetology, Ants, Bees, Animal BehaviorBat Conservation, and Species Modeling.

This is one of the signs you’re greeted with when you arrive (after driving down the long bumpy desert road into the canyon).

Of course, as scientists, it was tough for us to actually relax during the course. Every spare moment was spent collecting or exploring or reading or pinning… you get the idea. The first couple days we actually didn’t have that much to do and I started getting anxious! Thankfully, things picked up and I became totally absorbed in learning about leps. I work best when I have a million things to do and not enough time to do it all.

This is a view of some of the buildings at the station – with a typical early afternoon sky in the background. You could almost guarantee rain by 2pm. That’s the wonder of the monsoon season in the southwest – plenty of rain and rumbling storm clouds. I love this location – nestled in the Chiricahua mountains with streams and lush vegetation, surrounded by desert scrub. I was here last year with my advisor just to explore and catch caterpillars, and I’m already looking forward to possibly going back next summer. Some of the species in my study genus live here, so that’s a good excuse!

Of course at this point my mind and photos and notes are a little jumbled, with a big splash of excitement to talk about the adventures we went on. I’ll write a bunch of posts about the trip, not necessarily in order or corresponding to specific days. So let’s see what happens!

Ryerson Lab

Functional Morphology, Sensory Biology, Behavior, Biomechanics

I spell it nature

Trying to make sense of the world through science and language.