Saturday, October 09, 2010

Damn This World Is Complicated Part II: Beach Hoppers

OK, this one won't be as involved as the last one [Part I: Snowy Plovers.]   But remember, this is one of the main food sources of the threatened Western Snowy Plover, so it extends the discussion.  Our guide yesterday pointed out the beach Hoppers.  I grew up on nearby beaches and so I saw these as a kid, but I never knew their name and never looked at them carefully.  Beach Jumpers are small and much easier for me to capture in my camera so my pictures here will make up for the lack of photos of the Snowy Plover.   In fact, the digital camera makes it relatively easy to see them larger than you can with the naked eye.

So, let's get started with Beach Hoppers.

The Monterrey Aquarium website has a set of cards for kids that you can print out and learn about the beach life.  Here's their beach hopper card.

For more detailed pictures of a beach hopper labeled Orchestoidea californiana see Peter J. Bryant's website.

A 1964 Ecology article by Darl E. Bowers discusses two species of Orchestoidea - O. californiana and O. corniculata.  I'm guessing mine are californiana, but I'm not sure.  Bowers writes, in part:
"Competition for burrows between hoppers of the same species is commonly observed. In the early morning hours, large males may be seen fighting for possession of holes left open the night before. Fighting is presumably less energy-consuming than digging a burrow, but since most pugnacity is shown by mature males, possession of a burrow already occupied by a female is also of prime importance. Skirmishes for food items are likewise to be seen. Beach hoppers are eaten by an array of avian predators, mostly diurnal birds, and there is evidence that raccoons, moles, humans, beetles, and other animals take a toll of the hopper populations."
See?  As I said in the previous post, the more we know, the more we realize how much we don't know.  I was only vaguely aware of these critters before yesterday's beach walk and now I know quite a bit.

And it's a helpful reminder that we ought to dig a little deeper into all the important issues of the day.  They are more complex than we think, but a little research on the internet, finding a good book that gives an overview of the issues can help us quite a bit. 
Check the guys peeking from below has great pictures of beach jumpers and other animals living on the beach including kelp flies that will be in the next post.

There we learn:

Beach hoppers burrow under seaweed to escape the dryness and heat of the day. They prefer the damp sand under the piles of rotting seaweed. This picture shows what you might see if you pulled up a pile of rotting seaweed ... the beach hoppers will jump (hop) this way and that. It is very easy to identify a beach hopper because it is the only species on the beach that will hop. At night many of the beach hoppers are out of the sand and hopping around the beaches in search of food.

Hopping and digging in the sand require specialized legs as seen in these views [You have to go to to see their great shots] of the beach hopper's segmented body. The hoppers dig head first, inserting their antennae in the sand (left). As they dig their abdomen is the last part seen (right) before the hopper plugs up its hole. Beach hoppers are in the crustacean group whose members are called amphipods. The beach hoppers found on the sandy beaches of Santa Barbara belong to the genus Orchestia or Orchestoidea. Beach hoppers are sometimes called 'sand fleas' but they are not fleas (nor are they even insects) and are not able to bite humans.

Hey, don't get squeamish here.  These are like tiny, shell-less shrimp.  And without the kelp washing up on the beach for these critters to hide and feed in, the snowy plover would have to change how it eats. 

Beach Hoppers is also the name of a musical group, a bicycle, and a boat.

[Update:   Part III:  Kelp Flies

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