Friday, August 31, 2012

Science Video Friday - Parasitoidism in action

For parasitoidism being as gruesome as it is, the following video is surprisingly cute. I'll attribute that to the soundtrack. It also doesn't hurt that these wasps are parasitizing the eggs of an invasive stink bug, Halyomorpha halys, the brown marmorated stink bug.

Sunday, August 26, 2012

Late Summer Insects: Now showing!

Summer's starting to wind down (despite the temperature still hovering around 90 degrees on a daily basis), and that means new insects are now starting to make their appearances. One of my favorite groups are the assassin bugs, family Reduviidae, and late summer happens to be one of the best times to study them. Ohio's most charismatic species reach adulthood during this time, including the wheel bug (Arilus cristatus) and the jagged ambush bugs (genus Phymata).

The ambush bugs are small, stout assassin bugs in the subfamily Phymatinae. The family contains three genera in North America, and the most commonly-seen ones are in the genus Phymata. The subfamily hasn't received as much study as the rest of the assassin bugs, so your best bet for identification is to check out BugGuide's page. Dan Swanson has done some great work to figure out how to identify the Phymata spp., but it can still be tough.

A jagged ambush bug, Phymata sp., awaiting its next victim on wingstem.

Where are the best places to look for ambush bugs? Wherever the fall wildflowers are blooming. Roadsides and sunny fields are good bets, and it's usually worth your time to check out plants such as Queen Anne's Lace (Daucus carota), Goldenrod (Solidago spp.), Ironweed (Vernonia spp.), and Wingstem (Verbesina alternifolia). Ambush bugs prefer to creep around flowers, waiting for other insects to come in and land on the flower heads, and that's when the bugs grab them. Like other assassin bugs, ambush bugs have a proboscis they insert into their prey and use to pump in digestive enzymes. The bug will then stay a while, drinking up their milkshake.

These bugs come in a variety of colors: the picture above shows an ambush bug that's yellow with some green on its abdomen, but this can vary. These bugs exhibit some convincing camouflage, and if you want to find one on goldenrod, you may have to search for a while.

A golden ambush bug, Phymata sp.

Camouflage doesn't always help these bugs, however. You might not be able to see them, but sometimes you'll see their prey held, unmoving, above the flowers. Since dead insects don't have the power to levitate, you can be sure a predator is underneath, having a feast.

You may also encounter another vicious predator while walking through fields during this time a year, though you would barely know it as it flew by.

A gnat ogre, Holcocephala sp.

Believe it or not, the above fly is a robber fly, in the family Asilidae. Robber flies can be over an inch long, but this particular genus contains three species in Ohio, all of which could fit on your pinky nail. They're formidable foes of small insects such as gnats, small bees, and wasps, and are territorial. These ogres don't fear much, least of all humans, which allows people to get up close and personal with them. Macro lenses come in handy here. If the gnat ogre flies off before you can get your shot, just wait a while--it will probably come back and land on the same blade of grass in a few seconds.

There's a lot more out there waiting to be found, and many insects will disappear for the season while others start to emerge. If you want to see the beautiful Eastern Cicada Killer wasp, (Sphecius speciosus), for example, you only have a few more weeks left before it's gone for the year. Get outside and start looking now, before it's too late!

Tuesday, August 21, 2012

"It looks like an uncooked sausage"

One of my mantras when I go out to look for bugs and other critters is "Turn over that decaying log." You always have a great chance of finding neat stuff when you look through decaying wood, including creatures such as centipedes, millipedes, spiders, slugs, and of course, insects.

Today was no exception.

"O hai!"

After rolling over a particularly good log, I looked into a hole bored into the wood and found what one girl described as "an uncooked sausage" before she backed away to find some prettier biology. Despite its leathery appearance a bird or small mammal would look upon this beetle grub with much more glee. Then it would gobble this sucker down in a heartbeat.

A grub in the hand is worth...two in the log?

Judging by the size of this grub, I'm guessing that it's a grub of the Eastern Hercules Beetle (Dynastes tityus), though I'm not completely sure. I've uploaded it to BugGuide and hope to hear back about it soon. 

While decaying logs may not be the prettiest addition to wooded areas, they're still quite useful to the ecology of the forest. Without them, beetle grubs like this one would lose their only habitat, thus denying us their impressive beauty as adult beetles.

Monday, August 20, 2012

If it looks like a wasp, it's a beetle

The Japanese knotweed (Fallopia japonica) in my backyard has been a constant bane of my existence ever since it started to creep in a few years ago, but today it yielded some nice results. When it flowers during the summer, it brings in a lot of pretty bees and wasps, and today I found a wasp-mimic beetle.

The venerable locust borer, Megacyllene robiniae, was busily sticking its head into the knotweed flowers until I disturbed it. I took a few photos, then lifted my camera and realized the beetle was gone. Luckily, I was able to snap this photo of it folding out its wings to escape the paparazzi.

The locust borer is a longhorned beetle in the family Cerambycidae and develops as a larva inside of black locust (Robinia pseudoacacia), from which it emerges as an adult in the fall. It then nectars on flowers such as goldenrod and searches for a mate. This species takes its Batesian mimicry to the max--even the top of its abdomen, normally covered by its elytra--has the yellow markings that mimic a wasp. Now that's dedication.

I was hoping to find this species in my backyard, as I knew there are black locust trees around. I normally don't see adults of this beetle until the fall, so this was a nice surprise. Now to add this to my list of backyard species!

Friday, August 17, 2012

Science Video Friday - A Centipede's Song

It's time for a musical Science Video Friday, courtesy of a fan of house centipedes, Scutigera coleoptrata. I was very pleased after I found this video--not only is it about our many-legged friends, but it's very good and catchy. I sometimes find myself singing it from time to time. And some of the photos he features are pretty cute.

Saturday, August 11, 2012

Science Video Friday (on Saturday!) - Curiosity ignored the cat, landed on Mars

NASA continues to be the most inspiring arm of government we have in the United States. At the beginning of the week, millions of us followed along on the web as the newest Mars Rover, Curiosity, landed on Mars to begin its study of chemistry and geology on the Martian surface. A full-fledged mobile science laboratory, it landed on Mars safely after the "7 minutes of terror" experienced by mission control in Pasadena, California.

The Internet erupted in joy when Curiosity transmitted back its first image of  Mars, seven minutes after landing. For a video of the descent, NASA has kindly provided one, embedded below.

And as usual, XKCD has succinctly summarized just what exactly NASA accomplished.

For more info on the landing:
Yahoo News
Washington Post

Tuesday, August 7, 2012

The Thrill of Discovery

Max Barclay, the collections manager in the Entomology department at the Natural History Museum in London just posted something on Twitter that I had to share. It's an account Alfred Russell Wallace wrote about the butterfly Ornithoptera croesus, when he found a male of the species in Indonesia. From his book, The Malay Archipelago, 1869:
"The beauty and brilliancy of this insect are indescribable, and none but a naturalist can understand the intense excitement I experienced when I at length captured it. On taking it out of my net and opening the glorious wings, my heart began to beat violently, the blood rushed to my head, and I felt much more like fainting than I have done when in apprehension of immediate death. I had a headache the rest of the day, so great was the excitement produced by what will appear to most people a very inadequate cause."
The butterfly is now known as Wallace's Golden Birdwing, and he wasn't kidding when he wrote that other naturalists would understand what he experienced. While my experiences in Ohio haven't resulted in as showy of an insect, I have been dazzled by half-foot long wasps (if you count the ovipositor), a beetle the color of a Crayola macaroni crayon, and a beautiful Luna moth that hadn't yet pumped up its wings. In the moment when I realize I've found such stunning insects, I know exactly what Wallace meant. And after that moment? The whole day is filled with thoughts about that Amorpha borer or Luna moth.

In case you're wondering why a butterfly would give Wallace such a start, Wikipedia provides a plate from Reise Fregatte Novara. Zoologischer by Rudolf Felder and Alois Friedrich Rogenhofer showing the male and female, top and bottom, respectively.

While others may faint at the sight of an insect due to fear, we entomologists are liable to faint out of excitement.

Wednesday, August 1, 2012

Cicada Killers, Human Friends

Wasps: one of the most feared groups of insects. They're also one of the most hated, namely because of the propensity of some species to sting. If you've found yourself at the business end of a wasp, you probably weren't too happy. If I had to venture a guess, I would say that this is how many people view wasps:

But perhaps wasps don't deserve such a bad reputation. Many species of wasps play important roles in the ecosystem, including parasitism of caterpillars and pollination of flowers. Some aren't aggressive towards humans, for example the Eastern Cicada Killer, Sphecius speciosus.

Intimidating at first, sure. But not a threat!

This wasp isn't interested in ruining our day. The male might be interested in us at first, but that's because he's curious: he patrols his territory looking for females. If something new moves in, he has to check it out to see if it's a female he can mate with. You know, kind of like a teenager. The males can't even sting, though they can jab you with a sharp spine. The females, however, are able to sting. But you'll have to punch it in the face while holding it to get it to sting you. No, these wasps are interested in game closer to their size...

Now we're talking!

If you haven't already figured it out by now, the Eastern Cicada Killer kills cicadas. Aptly named, no? The whole story is more intricate, however. First, the wasp needs to catch the cicada. She will fly around, searching for her prey, and then snatch it out of the air. Out comes her stinger, and boom: the cicada is paralyzed. Not killed, mind you--that would be too easy. She drags the cicada back to her sandy nest and deposits it in an earthen chamber, along with an egg. After that, she seals up the chamber and flies off to catch more cicadas. The female may have many egg chambers in her nest, all sealed and containing a cicada or two. 

Don't forget that throughout this process, the cicada is still alive, sealed in its tomb. What comes next? Death by grub. After the baby wasp hatches, it devours the warm, nutritious cicada and pupates. Overwintering comes next, and after it warms back up during the summer, the adult wasp emerges and continues the cycle anew. 

By killing cicadas, these wasps act as an ecological equalizer for trees. They remove cicadas from the environment, giving the trees a break from being nibbled on by the musical Hemipterans. On a related note, wouldn't it be fascinating to measure the population of the cicada killers after a periodical cicada emergence? Perhaps the influx of so many cicadas allows their own populations to explode, resulting in a whole bunch of cicada killers (and scared humans) the next summer. Of course, that's only if the cicada emergence coincides with when the cicada killers are active. 2016 is the next year for Brood V in Ohio, so keep your eyes open.

On a final note, in case you're wondering what the species name speciosus means, it's derived from the Latin for "showy" or "beautiful." Another apt description for this wasp.