1994 Woodrow Wilson Biology Institute
NOTE: Read the dialogue out loud and ACT out all stage directions. (The stage directions will be found in parentheses.)
(Bitsy, a large wolf spider [Lycosa rabida] is crouched under a [what else] spider plant in a biology lab, carefully watching fruit flies in bottles. Itsy suddenly pounces into view!)
Bitsy: (with a startled yelp) Holy Arachnida, Itsy! You scared the silk out of me. Don't jump up on me like that!
Itsy: (surprised) Why, Bitsy, I'd think with 8 eyes you'd see anything coming! What are you so intense about?
Bitsy: (whispering from side of mouth) Keep it down, Itsy. I'm on the hunt in here; but if any humans see me - I'm flattened!
Itsy: Don't be silly. Humans are getting smarter about spiders all the time. They wouldn't kill you - you're too valuable in the ecosystem. And - if I do say so myself - you're an exceptionally fine example of Lycosidae at that! Although your temper needs a little work!
Bitsy: (with irritation) Will you keep it quiet! You'll startle the prey. Remember we don't use webs like other spiders. (flexing first pair of walking legs) We have to rely on our wits, our power, our size, our speed, our chelicerae!
Itsy: This is so true! So what are we hunting today?
Bitsy: Do you see those little flies over there on the shelf? (He points across the room) Those are dinner!
Itsy: Where are they? What are they?
Bitsy: Coordinate your eyes, Itsy. You can see in four directions, for goodness sake! Over there!! (wipes a little drool from mouth) Fruit flies; Drosophila melanogaster...those tasty little Insecta tidbits!! I usually don't get a chance to eat Drosophila, you know. They're hard to catch on the fly!
Itsy: (excitedly rubbing forelegs together) Let's get them! What are we waiting for?
Bitsy: Well, there's a little problem, Itsy. These flies are in jars, already collected for humans to use in the lab. We can't get at them. (Itsy looks depressed) But, never fear - I've got an idea! (Itsy perks up) We can catch our own!! (Itsy looks depressed again)
Itsy: I'm not sure about this idea, Bitsy. We'd have to catch an awful lot. They're quite small, only 2mm in length.
Bitsy: (very excited) We wouldn't need to catch that many, Itsy. Instead of eating them as soon as we catch them, we can let them mate and raise our own population! A moveable feast of never-ending flies....a fast food fly emporium! I'm a genius, Itsy, a veritable Ray Kroc!
Itsy: (worried) I don't know. I remember your last hunting experiment…the trap doors over our burrows!
Bitsy: (exasperated) You just have to bring that up, don't you. So I didn't get all the (heh, heh) bugs out...I'm still working on it.
Itsy: (whining) But I'm hungry now, Bitsy. How long will it take to raise our flies?
Bitsy: Once we catch some mating pairs, it will take about 2 weeks to get more adults.
Itsy: Two weeks!
Bitsy: But we'll get lots of adults, Itsy. We'll get small business tax incentives! And the new adults will continue to mate and lay eggs. A single female will lay several hundred eggs! The population will continue on its own. All we have to do is keep the jars free of fungi and give them food!
Itsy: Wait a minute! Did you say they lay eggs? We don't eat eggs - a little bacon maybe - but no eggs!
Bitsy: Itsy, I can't believe you hang out with me in the biology class. Take a look at that poster over there. Drosophila go through several life stages, just like all Diptera: the egg, the larva (which actually molts twice and is the source of some nice salivary gland chromosomes to study!), the pupa and the adult. All of these stages are easy to find in a population.
Itsy: (rubbing "hands" together) Let's get started! How will we catch them?
Bitsy: Catching fruit flies, the common name for Drosophila, is easy to do if you have warm weather and put collecting jars where they hang out: corner markets, supermarkets, garbage cans, even in houses.
Itsy: What food can we use to trap them?
Bitsy: Well, gee, Itsy....let's see. What kind of food would FRUIT flies like?
Itsy: OK, OK, I get it. (jumps up, ready to begin) So we're going to collect lots of Drosophila melanogaster!
Bitsy: Not so fast there Itsy. (Itsy sits back down) We may not necessarily get the wild type Drosophila melanogaster. There are a lot of alleles out there in the big city!! We're bound to run into them. As a matter of fact, we may not get D. melanogaster at all...there may be different species on every corner!
Itsy: (shivers) By wild type, I presume you're referring to the fact that they possess traits (such as red eyes and full wings) that are the most common expression in a population - NOT their fighting abilities!
Bitsy: (a little sarcastically) You're finally using your cephalothorax, Itsy! That is what I meant. The wild type fruit fly is a classic fly with 3 body regions; 2 large, red, compound eyes; and 3 pairs of walking legs and a nice pair of wings on their thorax or middle body region.
Itsy: (embarrassed) I'm a little embarrassed to bring this up, but how do we know if we get a (blush) couple?
Bitsy: It's pretty easy to sex fruit flies, Itsy. Male flies are often smaller than females. The posterior end of their abdomens is darker and more rounded than those of females and they have black sex combs on their front legs which are very distinctive.
Itsy: The Sex Combs. I think I heard that band last year…very loud.
Bitsy: (glaring at Itsy) You're not ready for the Comedy Club yet, Itsy. We can use the dissecting microscopes in here if we need any help in determining characteristics. Of course, keeping these flies still under the scope might prove to be difficult!
Itsy: No problemo, rabida. Carbon dioxide or ice will slow them down. If that doesn't work, we can always use a commercial anesthetic. But I have to say, Bitsy, that I'm still a little nervous about this project. I have lots of spiderlings to take care of. What if we don't catch any flies?
Bitsy: Well then, we can always call Carolina Carryout. They'll deliver any kind of fly we want, right to our front door. That is, as soon as that trap door is back in operation! All we have to do to order is call: 1-800-334-5551.
Itsy: (breathes a sigh of relief) Well that takes a load off my mind. Let's get started; (long pause) Uh, how do we do this again?
Bitsy: (totally exasperated) Holy tarantula, Itsy. Focus for just a minute and stop drooling. I'll explain it again!