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Thursday, June 06, 2024

Blogging Block - Mushrooms And Octopuses

I've got a bunch of started posts, but finishing them gets hard.  Don't want to just be another opinion without strong evidence.  Don't want to post simple stuff that has no meat.  Don't want to say what others have already said.  And it's summer - Anchorage is green and the temperature has crept up to cool but comfortable.  The garden's been taking my time up - I do enjoy seeing everything that's popping up.  Seems most of the perennials have survived the winter.  Also have been pulling up dandelions - first, to get them before they go to seed and second to add the greens to the compost pile.  Still have lots of dead leaves and they need to be layered with fresh greens (and the kitchen compost).

Found a couple of morels had popped up yesterday.   



And getting that picture up reflects one of my obstacles - my airdrop to my laptop stops working after a while and I have to shut everything down and reboot to get it to work again.  



I'm reading David Scheel's Many Things Under a Rock:  The Mysteries of Octopuses for our next book club meeting.  I'm enjoying it immensely.  It's a pleasure to read, I'm learning about octopuses - what they prey on, who preys on them, and how they evade their predators, for starters.  

David Sheel teaches at Alaska Pacific University and has accepted our invitation to join us when we discuss his book.

Sheel writes that "many things under a rock" is a translation of the Eyak word for octopus.



Here's a sample:

"The giant Pacific octopus of Port Graham that had defeated the butter clam mentioned earlier ha taken the heavy bivalve in its suckered arms.  But she was to learn the limits of her strength.  With many suckers on multiple arms attached around both halves of the clamshell the octopus no doubt had tried to pull open this armored prey, perhaps with some patience.  The sucker attachment requires no persistent force, but the octopus has to pull continuously with its arms to pry apart the clam halves, while the clam resists, applying opposing force to hold itself closed. 

Watching an octopus apply this pressure can be a quiet affair.  If the clam wins, this may be a motionless tug-of-war.  With small clams, a giant Pacific octopus quickly and smoothly pulls the clamshell open, sometimes with enough force to break one of the clamshells.  The day octopus opens clams and pries loose prey from their holdfasts on the reef with a series of sharp pulls, its who body jerking until, sometimes with an audible crack, something breaks and the inner flesh is accessible.  The day octopus is very fast, often breaking into its prey or moving on within less than a minute, whereas the gist Pacific octopus my spend a few minutes to tens of minutes opening prey by pulling.  

In its battle with this large butter clam, the octopus tired first.  The clam was too strong, and did not yield to the octopus's strength.  So the octopus tried something else.  On the outside of the clamshell were no fewer than I've separate marks, two marks on one have of the clamshell and three marks on the other side.  The marks were small ovals mea by the giant Pacific octopus.   Each of those was an attempt by the octopus to get through the shell.  

These tiny oval perforations are drill marks.  Octopuses have inside their mouths a radula, which is a rising organ used to break up food.  The radula itself is a ribbonlike membrane  that runs between two muscle groups and lies over and between the posters, two muscularhydrostats.  Our human tongue, as well as octopus arms and the elephant's trunk, are muscular hydrostatic - anatomical constructions that use fluid pressure generated by muscle contractions rather than a rigid skeleton to allow movement.  Inside the octopus mouth, the bolsters can direct the pressure of a bend in the radula ribbon.  Along the length of the radula are rows of micro teeth.  Muscles at either end pull the radula back and forth, rasping it over and wearing away the surface against which it is applied.  

The radula begins the work of drilling, and is sufficient itself to make a hole.  But it cannot penetrate too deeply.  Beyond that, the salivary papillae, also tipped with a few rasping teeth must take over.  The salivary glands secrete enzymes that break dow the shell of prey such as crabs or this clam.  The papillae delivers the caustic secretions directly to the drill site, chemically dissolving the shell, and making it easier for the tooth-tipped salivary papillae to rasp away."

If you are having trouble imaging an octopus radula, here's a picture google says is an octopus radula.  Unfortunately, the link resulted in "Page Not Found."   I don't quite see the rest of the octopus so I'm still a bit confused.  But this helps a little.  



Additionally, I'd note, as I have on occasion that I am still posting about the Respiratory Disease Reports from State every week.  There's one more today.  You can find those at the Respiratory Virus Cases tab above (just under the orange banner.)  You can also go there with this link.  But I'd rather you find the tabs so you can check it any time.  This week COVID cases are up significantly while only one RSV case was reported, and the flu cases are down slightly.


So, many things under a block.  

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