Best of youtube #6: The Guild

If you're a fan of Joss Whedon, you'll certianly recognize Felicia Day.

It's a series about a group of people who are addicted to a World of Warcraft type game.

New Sciency Stuff Coming Soon...

I'm actually working on a few things right now. Both about parasitoids...expect them soon.

But let's review exactly what a parasitoid is. A parasitoid has characteristics of a predator and a parasite. They live within their host, taking nutrients from them kind of like a parasite. However, very much unlike most parasites, they eventually kill their hosts as well.

Let's take a tapeworm, for an example we can use to contrast between a parasite and a parasitoid. The dumbest thing a tapeworm could do is to kill it's host. Why would it? It's got it made-nice safe environment in the gut of some animal that keeps it safe. All the food it could ever want delivered to it...it doesn't have to chew, that's done by the host. All it's had to do to survive is evolve into an inside-out intestine and become hermaphroditic.

Remember this scene from the movie Alien?





You know, the creature that emerges from Kane at about 2:00 in?

That's what a parasitoid is. A bit of a greusome example but to me, parasitoids are only beautiful because they're so damn ugly in the way they live their lives. All parasitoids are larvae. They're either hymenoptera or diptera...wasps and flies, respectively. There's a few butterflies and beetles which are parasitoids as well. Even though parasitoids are extremely different from one another, they all have an adult stage that's free living. This is why they can afford to kill their hosts.

True parasitic relationships in the insect world are rare. The only example that immediately comes to mind is Strepistera...twisted-wing parasites which live inside wasps. They actually do some really cool things, like extend the lifespan of their host.

They come in two flavors...idiobionts, which eat their host as-is and don't allow it to grow or moult any further and koinobionts which benefit from the extended development of thier hosts, usually not killing their hosts until they pupate. Parasitoids can either live inside or outside their hosts. If they live on the outside of their hosts, they're called 'ectophagous parasitoids'. Ecto = outside and phagous = eating. Parasitoids that live inside their hosts are called endophagous parasitoids, which means 'inside-eating'.

Parasitoids that parasitoids parasitoids are hyperparasitoids. Parasitoids that parasitize parasitoids that parasitize parasitoids are 'tertiary parasitoids' so on and so forth. It's confusing as hell, but that's what I'm here for.

So...why do I love parasitoids so much?

Well, they violate everything we hold sacred. They violate the body by burrowing inside it and consuming it from the inside-out. They violate the mind by taking control of their hosts. They violate this absurd notion that life is sacred by using their host until it can't give any more and then killing it. Any notion that we might lose our spot at the top of the food chain is absolutely horrifying to us...and Hollywood plays on those fears in many big and low-budget movies. It's definitely not a bad thing...I'll be comparing parasites to various Hollywood monsters in many of my posts.

Parasitoids have some really cool adaptations to compete amongst themselves and to subdue their hosts. Some are neurosurgeons, and I've mentioned that some take over their hosts. Some fight wars inside their hosts, and some produce their own viruses. Some parasitize other parasitoids and some parasitoids even parasitize themselves.

So. Yeah. Parasitoids are really cool. They really are miniature real-life horror movies. Because, you see, we have creatures almost exactly like the creature from Alien here on Earth...it's not a unique creation of Hollywood.

Critters which are known as bee-flies (Family Bombyliidae) actually resemble the creature from Alien even more than the hymenoptera (parasitic wasps) it's generally associated with. Remember how Kane first got acquainted with the critter from alien?

Well Bombyliidae actually have a similar manner of host location, where the larva finds the host after the adult lays the egg. The first instar larvae of these guys kind of have legs and actually look for their hosts. When the larva finds a suitable host, the larva burrows into it, moults into a maggot that looks a bit more familiar, feeds and then exits it's host as parasitoids do. Then it pupates and emerges as something which looks a lot like a bumble-bee.

So Alien isn't exactly a new creation...we've had something like it for a few million years or so. It was just a little bit smaller than we expected.

Oh, Ray Comfort says he's not a prophecy buff...

...but you just know that when something goes awry, he's praying for the world to end.

Just in case you've lost track of the score, here's where we stand:




Yup...instead of overhauling the US bank system, we need to start hoarding food and preparing for the four horsemen.

Just out of curiosity though...if this is a sign of the coming apocalypse, why didn't the world end in 1929?

So I'm horrible at this whole blogroll thing...

...and I've finally started one.

Check them out in my profile.

New Sciency stuff coming real soon. I'm switching gears a bit because I have a major case of ADD, but I think y'all are gonna like it.

I'll return to the whole history of entomology thing soon-ish. I still need to go over what happened when Koeble landed in Hawaii...the story isn't over.

But I'd like to go through some parasitoid basics first...some extremely odd aspects of their different lifestyles and how they're used in biocontrol.

We'll begin with exploring exactly what parasitoids are, then adelphoparasitism and then explore biological control with hyperparasitism before careening into tachinid metamorphosis.

You ready?

A lot of shit to get in for a couple ball pythons...

...I sincerely hope the tarantulas were rare.

http://www.cnn.com/2008/WORLD/asiapcf/09/24/snakes.spiders/index.html

Exotic pet smuggling is a problem for both hobbiests and environmentalists. Some of the worst ecological disasters result from introduced species of plants and animals. The people who regulate shipping into and out of countries know this, and this type of thing gives a bad rap to people like me who love to keep spiders.

I do keep spiders. I have about 50 or so. The species on my profile is called Phlogellius vulpinus (I believe it's now synomized with Selenocosmia vulpina, but I don't keep up on my taxonomy as well as I should). It's incredibly rare...less than 10 were in the whole US the last time I checked so that gives you an idea of what my collection is like.

I only buy captive bred. And there's a huge movement within the hobby for captive breeding programs for most species. Nowadays, mature adults are only imported a few times and then bred until it becomes uneconomical to import full grown adults.

Unfortunately, it looks like this package was headed for Sydney, Austraillia. Even though they have some of the coolest animals on the planet...pretty much everything endemic (including the spider in my profile pic). Unfortunately, this is a continent that has been hit hard in the past by introduced species and any action they'll take is pretty much justified in my eyes.

Youtube Gems: Katy Rose

I have a science post coming up on Friday, thanks to the 'schedule post' function so I figured I'd do a music post this week.

This song is called Catch My Fall by Katie Rose and you can find the lyrics here.

The clips in the background are from the movie Thirteen which is about a young teenage girl (played by Evan Rachel Wood) who discovers drugs, sex, crime and numerous other bad things through the help of the 'popular girl'. It's a coming-of-age clique story, but it's the fucked-up version which shows the things you'll never see in a Lindsay Lohan film. It deals with drug addiction, depression and shows cutting as well as a handful of other things I remember seeing a couple of my friends going through back in my early high school days. The movie deals with it's themes bluntly and honestly without trying to glorify or euphamize anything which happens during the course of the movie.

I guess the honeymoon is over...so much for the afterglow.

So after an entire summer of waiting, I have my first round of tests this week. And another custody battle to go through.

So my next week is going to be a blur of bugs, chemistry, ecology, lawyers and dealing with all sorts of people I don't really want to see.

Anyways, I have a post scheduled to post on 9/21 and I've decided to start doing a weekly Best of Youtube post when I don't have a science related post to offer. So you'll have plenty of bug related shiny objects to keep you occupied until I return.

The first Best of Youtube, a video from the documentary Planet Earth about a parasitic fungus called Cordyceps.

Larry Fafarman, AIG, The ICR and Poe's Law

The idiocy of creationists and people like the Discovery institute never fails to amaze me. Or amuse me.

I mean, they've peddled the same bullshit for decades without ever realizing that their arguments are, in fact bullshit.

Of course, they cover it up with dishonesty, bad arguments (specified complexity, anyone?) and just ad-hoc reasoning in general.

Of course, one of the most prevalent things that I've noticed is that they'll take any excuse to attribute their own faults to athiests.

The latest example is Larry Fafarman. You'll be familiar with him if you post over at scienceblogs. He's a persistant pest in the blogs of anyone who writes about evolution.

Anyways, it seems that Fafarman doesn't realize that The Onion is a fake newspaper that runs satirical articles.

http://im-from-missouri.blogspot.com/2008/09/pilgrims-worship-darwins-image-in-wall.html

He cites an article where athiests supposedly flocked to a stain that beared a resemblance to Charles Darwin. The article is meant at ridecule, but people frequently flock to the images of the Virgin Mary, Jesus and such. Rank hypocrisy.

It's bad enough that Answers in Genesis seems to think that every bigfoot hoax is proof against evolution. Even the ICR falls for things like April fools jokes.

The reason they do this is because they're simply not interested in honest debate. When they do actually participate in one, they generally get crushed under the weight of the evidence.

Ever wondered what happens when an insect sheds?

Quite a bit of what I blog about is going to come from my entomology class notes. To me, blogging is a way to help me understand various papers by forcing me to read them and then regurgitate the information in a form that's easy for people to understand. This is no different.

Before I go into all the hormoney goodness that is the moulting process, first we need to understand exactly an insect grows and how it's body is set up.

An insect is covered in a shell called an exoskeleton. It doesn't look like it, but insects are basically wearing suits of armor. All the time. It's actually pretty cool, and it's great protection. In some cases, especially ironclad beetles but sometimes velvet ants, entomologists actually have to drill holes in the insect before pinning it.

The whole exoskeleton thing is great...but there's a problem. It's too damn good. The insect actually can't grow because the exoskeleton can't expand with the insect. The insect solves this problem by changing it's clothes. Here's an example. A larval cicada looks something like this:



Yes...the pictures suck. I know. Blackberry needs to make a cellphone camera with a macro function.

So what, exactly is this exoskeleton made of? It's a polymer, kind of like plastic (but not). It's made of proteins and chitin. The insect's epidermis ('skin'), only a few cells thick, sits beneath it and is more or less attatched to it.

So...what makes that little bug turn into one of those things which scream for ladies at the tops of trees?

Well first specialized cells in the brain, called neurosecretory cells secrete a substanced called 'brain hormone'. The brain hormone then circulates in the insect's bloodstream, where it ends up in a gland at the front of the thorax (prothoracic gland). This gland then secretes another hormone called ecdysone (ecdysis=moulting). Ecdysone is the hormone that directs the various activities related to moulting.

The cells in the epidermis start rapidly dividing in response to ecdysone and becomes closely packed. The exoskeleton then seperates from the epidermis in a process called apolysis. At this point, a substance called moulting fluid is produced.

Moulting fluid contains all sorts of proteases and chitinases (protease=noms proteins, chitinase=noms chitin) which digest almost all of the old cuticle. The digested cuticle is then reabsorbed and recycled by the insect.

While the old cuticle is being digested, the new cuticle starts growing. There are several layers that are formed, but the important thing is that the outer layer is resistant to enzymes. When everything from the old cuticle is absorbed and when the new cuticle is complete, the insect actually sheds it's skin.

The whole thing is initiated by a hormone called eclosion hormone which is secreted by the brain. When the insect moults depends on the species. Some insects just moult when they find a nice, cozy place and some moult at specific times of days. Either way, the actual process is pretty similar through all insects.

The insect swallows air or water and raises it's blood pressure and this causes the exoskeleton to split along already weakened lines. The insect just kind of squeezes out, usually head and thorax first. After this happens, the insect expands it's cuticle by again swallowing air or water and using blood pressure to expand the cuticle. At this time, the cuticle is pale and soft and the insect is vulnerable. It soons hardens and becomes pigmented again. This process is controlled by another hormone called bursicon.

These hormones, and others are sometimes used in pest control. I'm sure I'll eventually write a post about those hormones, as well.

Here's what that little bug turns into, by the way:





Here's a time lapse video of the same thing:



Pedigo, Larry P., Rice, Marlin E. (2009). Entomology and Pest Management (6th ed). New Jersey: Pearson Education