Regarding the mortality of smallish critters:
I don’t imagine in the boom-and-bust population cycles and evolutionary methods that propagated the fast-reproducing and fast-dying insects, arachnids, worms, and altogether gooey things would make fighting disease of consequence, but I still wonder:
Do invertebrates have immune systems?
Perhaps their resistances are simple as the pH level of internal fluids producing an inhabitable environment for parasites and stowaways, and perhaps entomologists have more pressing interests than grasshopper measles.
Still, cut a worm in half, and it will still persevere.
So, any ideas?
BTW, I was just sitting there, thinking, “Oh, jeez, that’s a good one to as Cecil Adams.” Then I thought “Well…I suppose the ethical thing to do is try and answer it first, rather than just try to catch some limelight without some research…” Heh, I guess it’s just a question for the chronically inquisitive.
Yes, invertebrates have immune systems. Interestingly, researchers found just last year that C. elegans and humans share at least one specific immune system path. There’s a great paper on this in “Science” but unfortunately, you must ba a subscriber to access it. Here’s a link with some key information however. http://www.mgh.harvard.edu/news/releases/072502immunity.htm
And here’s a link to a really informative site about invertebrate immunity. http://www.aquarium.net/0498/0498_1.shtml
Hope this helped!
Interesting article, Amberlei. One very important component of the invertebrate (and vertebrate and plant, for that matter) immune system is the group of molecules known as the antimicrobial peptides.
Antimicrobial peptides seem to non-specifically punch holes in the plasma membranes of invading pathogens (although this point is controversial). For this reason, they are being investigated as a possible alternative to classical antibiotics, which are becoming more and more useless.
Here’s a link:
http://www.univ-lille1.fr/lea/Menu_du_Site/Publications/Acrobat/RU84%20Salzet%20proof.doc.pdf
-Apoptosis
Wow, that’s some wild news!
Just to clarify things for me, as my comprehension didn’t improve much with several trips to dictionary.com…
The nature of these defenses is more akin to laying down caltrops, rather than learning cells that seek and destroy, correct?
Also, the molecules in question were previously unnoticed due to size…?
er- you want to be careful cutting worms in half- nothing more advanced than a planarian would regenerate both parts,
and most worms would not survive this treatment.
SF worldbuilding at
http://www.orionsarm.com/main.html
Hey MSMStud,
In general terms, the vertebrate immune system can be divided into two branches- innate and adaptive. The former consists of elements that are constantly present and are non-specific (e.g. phagocytes). The adaptive branch is pathogen-specific and is activated by the innate branch only after a pathogen has entered the body. The lymphocyte (including T and B cells) is the hallmark of the adaptive immune response. Invertebrates lack these cell types (and therefore lack antibodies), but do possess phagocytes, antimicrobial peptides, etc (see Amberlei’s second link above). In that sense, the invertebrate system is more like caltrops rather than specific seek and destroy weaponry.
Not sure what you’re getting at here. Antimicrobial peptides were discovered several decades ago. Glucose is a small molecule, but its existence has been recognized for a very long time.
-Apoptosis
Okay, thanks for clarifying that! 
sorry, misposted. Intended message:
I forgot how recent the developments in antibiotic-resistant diseases were. I figured this branch of innate immunity would have been simpler to advance and improve. I guess the said molecules are harder to formulate than educating an intelligent immune system with crippled diseases.
Ok, thanks, I think I’ve got a good picture now.