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About the video conference we had today:
How many caterpillars are typically found in the beat sheets?
If the caterpillars have to defend themselves from parasitoids AND predators, why can't they just adapt to defenses that protect them from both predators and parasitoids?
From,
Krystal

Hi, Krystal!

I love your questions! We do a visual search for the caterpillars first, because we might miss the caterpillars who avoid parasites and predators by dropping to the ground when we beat the trees. It would seem like they would drop into the sheet, but as soon as we whack one side they feel the disturbance and start dropping from the other side, too, and then we miss them. Since we pick all of these guys off, typically the ones that are left for us to beat off are the cryptic ones - the ones that look so much like twigs or leaf veins that you can look right at them and not realize it's a caterpillar. (Did you see that one we think might be a Maple Looper? It was lying right on the leaf vein!)

Since we've gotten a lot of them already, we typically get between 2 to 5 when we beat.


About adaptation:
Here's the thing, we haven't discussed how adaptations occur. Organism's don't really "decide" to adapt. What happens is, different individuals of the same species are sometimes better at a particular thing that becomes important for survival.
For example, all polar bears know how to swim. But because of climate change, the ice is melting and they have to swim farther from one ice floe to another. Only the really great swimmers will survive, the others will drown. Since babies are like their parents, the babies of the surviving bears will probably become better and better swimmers. The drowned ones don't have babies, so their traits don't get passed on. See? It's called "Natural Selection". The great swimmers are naturally "selected" to reproduce. The trick is, for the adaptation to show up in every bear, it takes a really long time because it takes generations and generations of bears for all the good swimmers to die, and for everyone whose left to become a really great swimmer.
If none of the bears was born a great swimmer, the species would eventually become extinct.
In the case of the caterpillars, some individual a really long time ago happened to vomit when a predator tried to eat it and it got away. Maybe it had been born with a really sensitive gut. The ones who didn't vomit got eaten. So the pukey one lived to have pukey babies and after many generations of pukey caterpillars getting married to each other and having babies, most of the caterpillars of that species can now avoid predation. But it just didn't happen to work out that an individual of that species has a physical characteristic or behavior that helps them avoid parasitism. BUT they haven't gone extinct because the number that get parasitized is low enough for them to survive as a species.
Stay tuned, though, they'll figure it out any millenium now....

Keep thinking, science girl!!
Have a fun and safe Halloween!

Mrs Feynman
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Paula,
Great to follow your adventure. I'm sorry I missed your podcast to the Loring 4th grade, walked into the classroom just after you ended.

Its good to know that your group is discerning.

Be safe and keep up the good work,
John Brackett

Hi, Dr. Brackett -

Thanks for checking out my blog. I think you are referring to our ability to discern between caterpillars and twigs, or caterpillars and bird poo. Yes, indeed, this work is not for the meek.

I'm sorry you missed our "talk", too. Ms. Burney's fourth graders are awesome and asked great questions. They are busy studying rocks and minerals right now, but they got really excited about going out to the field. We're really lucky in our district to have teachers like Ms. Burney and Ms. McCarthy who work so hard to make science so engaging.

Are you trick or treating tonight? Make sure to wear reflectors!

Mrs. Feynman