Nibbling

  

I was helping Emma and Fern scout some potential research sites this afternoon (9 July 2022) and we started to notice some Western Tussock Moth caterpillars (Orgyia vetusta) in the high intertidal zone.  Eventually we discovered that the caterpillars were coming from the top of the bluff where they had been feeding on lupines.  At one point Fern looked down to see the scene shown above — a Lined Shore Crab (Pachygrapsus crassipes) feeding on one of the caterpillars!  I haven't seen this before, so it seemed worth documenting.

Earlier in the day I had noticed a few of these caterpillars, but in this case what caught my eye is that the caterpillars were eating seaweed!  Here's a Western Tussock Moth caterpillar nibbling on Ulva intestinalis:

 

 

P.S.  With thanks to Fern and Emma for sharing their observations today!

An iridescent neighbor

  

This snail can be quite common in the rocky intertidal zone, but it's small enough (only ~4 mm long) that you might not notice it.  Meet Lirularia succincta!  Photographed 4 July 2022.

Update about NHBH e-mail service

  

This is a quick note to let everyone know that I'm transitioning to a different e-mail service for the Natural History of Bodega Head blog post e-mail messages.  

If you subscribed to the e-mail service before last summer, you have been receiving messages from Google (Feedburner).  However, that service has been discontinued (although I know some of you have still been receiving occasional messages). Soon you will no longer receive messages from Google.  

The new e-mail service is called follow.it.  If you have signed up to receive blog posts in the past, then you might see a banner at the top of the new e-mail messages explaining that I have transferred subscribers to the new follow.it service.  This is a legitimate message.  You can click on a link to confirm you'd still like to receive e-mails from the Natural History of Bodega Head.  Or you can also decline if you no longer want to receive these e-mails.

Also, if you know anyone who tried to subscribe during the past year and wasn't successful, the good news is that you can direct them to the bottom of the main NHBH web page where the subscription form is now functional.

I apologize for the issues with the e-mail service during the past year.  I'm hopeful that this will be a workable solution.  Thanks again for your interest in the Natural History of Bodega Head!

P.S.  The photo shows an Elegant Tern...because I'm turning the page to a new service!  :)

The Dove Snail Attacks!

I had a bit of an eyebrow-raising experience today.  I was trying to photograph a common snail, the Carinate Dove Snail (Alia carinata).  This marine snail can be found in a variety of habitats, e.g., rocky shores in tidepools and among surfgrass and seaweeds and in harbors among eelgrass.  It's fairly small (most individuals are probably ~10 mm long), elongate, and usually brownish/black in color.  Here's an example:

 

 

This species is common enough that you can overlook it.  But I needed a photograph, so I was looking at several of them under a microscope today when I came across one in a puzzling position.  I wasn't sure what was going on at first:

 

 

 

So that's the snail, with its siphon extended up and to the right and its foot flat against the surfgrass blade (in this photo the foot has blue highlights).  You can see the snail's short tentacles, and you can also see a small dark eye on the right hand tentacle.  But what's below the tentacles?  Here's a side view:

 

 

 

Ahhh!  The snail had extended its proboscis (a tubular feeding structure) into an egg capsule filled with developing larvae.  It was vacuuming up the veliger larvae!  I hadn't seen this behavior before, so I wasn't sure I was interpreting it correctly at first, but there was no doubt.  The snail reached around inside the egg capsule and cleaned out almost every developing larva.  (The egg capsule/larvae belong to a different snail species, Lacuna marmorata.)

 

Even better, Eric wasn't far away and he came over just in time to capture a video of this fascinating feeding behavior (see below).  

 

I loved learning something new and unusual about a common local snail.  In some ways the name "dove snail" suggests a rather sedate snail, but I'll never look at Alia the same way again!

 

And here's the best part — the video!  Watch for the snail approaching the egg capsule, inserting its proboscis inside, then using suction and its tongue-like radula to ingest the tiny larval snails.  You'll see the radula flicking in/out at the tip of the proboscis.  (At this stage, the larval snails have shiny little shells.)

 

 

 

Many thanks to Eric for a memorable video!

 

Stars and stripes

 

 

Northern Opalescent Nudibranch (Hermissenda crassicornis), photographed 1 July 2022

 

Happy Fourth of July!

 

Olive's at the coast

  

Eric's class was conducting a nudibranch survey recently, and thanks to Zoe's sharp eyes we were introduced to an interesting sea slug — meet Olive's Sapsucker (Hermaea oliviae)!  This is the first time we've encountered this species.

It's easy to understand why this sea slug isn't seen that often.  They're tiny — this one was only ~5 mm long.  And they look a lot like the algae they eat — in this case, Polysiphonia (perhaps Polysiphonia hendryi).

Sacoglossan slugs look similar to nudibranchs, but note the rolled (rather than rounded) rhinophores (the sensory structures that look like tentacles in front of the eyes).

Here's the entire animal (below).  It was fun to see them cruising around!

 

 

P.S.  With many thanks to Zoe for spotting such a cool little slug! 

 

P.P.S.  Thanks to Jeff for assistance with this identification.

 

P.P.P.S.  For an example of a different species of sap-sucking sea slug, see the post called "One cell at a time" on 23 September 2017.

Early summer

  

Early summer view with the yellow-flowering shrub called Lizard Tail or Seaside Woolly Sunflower (Eriophyllum staechadifolium), 30 June 2022