Selasa, 02 Juli 2013

Malaise Traps and Mites

I'm now officially a graduate student at the University of Arkansas--kind of my way of starting July off with a bang. My first two days have been jam-packed with information that I'm still trying to digest, and what better way to do that than to share it?

I started off my first day by assisting another student in the lab in setting up a few malaise traps. Our goal for the day: set up four of them. Spoiler alert: we only set up two of them due to a broken trap and not nearly enough cord. But hey, two is better than one. Or none.

We set out for Lake Wedington, west of Fayetteville, and found a nice spot on a slope in a patch of secondary succession forest. It looked like a good flyway for insects, so we set up the trap. A malaise trap catches flying insects and funnels them into a container (usually filled with ethanol), from which they're collected after a few days. We felt good about the location we chose, since we were already seeing some flies, wasps, and other insects flying around us as we set up.

Lycomorpha pholus - Black-and-yellow Lichen Moth

The blurry picture above shows the Black-and-yellow Lichen Moth (Lycomorpha pholus), which kept landing on me as we set up. I noticed a few of these moths flying around brazenly, seemingly protected by their mimicry of the Lycid beetles. Its common name is something of a misnomer: it's actually orange with bluish-black wings. It looks similar to a moth I've often seen in Ohio, the Orange-patched Smoky Moth (Pyromorpha dimidiata).

To ensure that our prey didn't simply fly under our trap, we stacked up a few rocks and logs at the bottom of the trap. The first log I picked up had a pretty garter snake under it, which promptly disappeared under the leaf litter. Another had a caterpillar.

I thought it was dead at first.

I'm not sure what species it is, but it blends in well with the wood.

Next we trudged up the slope to an oak opening that was filled with grasses and the song of a nearby cicada. We searched for a nice flyway, and decided on a spot near where we found a ladybug, parasitic wasp, and metallic wood-boring beetle (Buprestidae). On our walk to the site, I glanced down and noticed something hidden in the grasses.

Small flowers, or huge fingers?

I knew it was an orchid, but didn't know anything more. I remembered seeing a photo of this species before, however, thanks to Andrew Gibson, so I sent it to him. He promptly returned a species ID: Grass-leaved Ladies'-tresses (Spiranthes vernalis). The orchid is about a foot tall, and the small white flowers wind up and around the stalk. 

After we finished setting up the second malaise trap and had thoroughly complained about the broken trap and lack of cord to set up anymore, I heard a buzzing sound and looked at a nearby oak branch. At first, I thought it was a leaf-footed bug (Coreidae), but realized it was something more interesting.

Of course it's an assassin bug.

A stout assassin bug, one of the Bee Assassins (genus Apiomerus), had flown nearby. This one is Apiomerus crassipes, an assassin that ranges from the central to eastern US. I don't often encounter these guys, so it was an exciting find for me. Other species in the genus can be brightly colored in red and yellow, but this species apparently opts for a sophisticated black with red accents.

After my foray in the field, it was time to sort some leaf litter samples. I found some interesting beetles, a few centipedes and millipedes, and other miscellanea. However, I'm working in a mite lab, so it was time to learn some mites. Mites 101 consumed my second day.

To summarize, there's more to mites than just velvet mites, which are the ones I'm vaguely familiar with. Much of the diversity in mites is in the suborder Prostigmata (which does include the velvet mites), and I took a few photos of various groups within the Prostigmata for my notes. I'll include a few here, if for no other reason than to show some mites you may not know about. All these mites are pretty tiny, so these photos were taken through a microscope.

Labidostommatina mites. Large chelicerae (can't really see in the photo), predatory.

Whirligig mite, family Anystidae. Legs appear to originate from central point.

Snout mites (Family Bdellidae, genus Bdella). Look kind of cute.

Smarididae. Mites with mouthparts inside their body, which they can vomit up. Have setae on their bodies that make them look oddly fuzzy.

I'm still processing a bunch of mite information, so I'll stop here, rather than write something potentially wrong. It's neat to learn about this group and see the diversity, and hopefully I'll get it organized in my head soon.

Now to get some sleep before heading back to the lab tomorrow.

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