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Over the Memorial Day weekend I took my students out on the early morning low tides at Natural Bridges State Beach.  While they were ooh-ing and ahh-ing and filling out their assignment worksheet, I was playing around with my new camera, taking pictures in the water.  Because I am not a photographer and sea anemones just sit there, they quickly became my favorite subjects.  Not to mention the fact that they are simply  beautiful and photogenic creatures.

At Natural Bridges we have four species of anemones in the genus Anthopleura:

  • A. xanthogrammica - giant green anemone
  • A. sola - sunburst anemone
  • A. elegantissima - aggregating anemone
  • A. artemisia - moonglow anemone

Of these species, the first two are notable for their large size.  At Natural Bridges they can get to be the size of a dinner plate.  They live side-by-side in tidepools, and since there are many deep-ish pools at Natural Bridges they are among the most conspicuous animals in the intertidal along the northern California coast.

Anthopleura sola (left) and A. xanthogrammica (right) in a shallow pool at Franklin Point.
Anthopleura sola (left) and A. xanthogrammica (right) in a shallow pool at Franklin Point.

It's easy to identify these animals when they're sitting right next to each other.  The difficulty comes when you see only one in a pool by itself with nothing to compare it to.  In a nutshell, here are some things you can use as clues to determine which species you have in front of you.

Let's start with Anthopleura xanthogrammica, the giant green anemone.  This animal's oral surface and tentacles are a solid color, varying from bright green to golden brown.  There are no conspicuous stripes on the central disc and the tentacles are relatively short and stubby, without any white patches.

Anthopleura xanthogrammica, photographed at Natural Bridges State Beach
Anthopleura xanthogrammica, photographed at Natural Bridges State Beach

Anthopleura sola, on the other hand, usually has distinctive radiating lines on the oral disc.  Hence the common name of Sunburst Anemone.  Its tentacles are generally longer and more slender than those of A. xanthogrammica, and often have sharp-edged white patches.  Sometimes the tips of the tentacles are tinged a pale purple.  Anthopleura sola are usually brownish-green in color, and I haven't seen any that are as bright green as the A. xanthogrammica anemones.

Anthopleura sola, photographed at Natural Bridges State Beach
Anthopleura sola, photographed at Natural Bridges State Beach

That's all well and good, but sometimes you come across an individual that doesn't completely follow the rules.  Or rather, it looks like it could belong to both species. Such as this fellow (fella?):

Hmmm...sola or xanthogrammica?
Hmmm. . . sola or xanthogrammica?

The animals obviously don't read the descriptions.  This one has xanthogrammica shape and overall color, but those lines on the disc read as sola-ish.  I would call this one a xanthogrammica.  What do you think?

The birds do it, the bees do it, and now the frogs are doing it.  There's a small clump of trees between two of the houses across the street, and I think that's where a male Pacific chorus frog has staked his claim.  Every evening for the past few weeks I've heard him singing away.  Often you'll hear several frogs singing at the same time, but this particular guy's call is much louder and more piercing than the others.  What I particularly like about this sound recording is that it begins with a solo, and other frogs join in to make a joyful noise.

The Pacific chorus frog (Pseudacris regilla), sometimes erroneously referred to as the Pacific tree frog, is the only frog that ribbits.  It couldn't possibly be mistaken for anything else.  In fact, its song is so iconic of "frogness" that it is universally used in movies and other Hollywood products taking place anywhere in the world, despite the fact that this little singer lives only along the western coast of the US.

Most Pacific chorus frogs don't live in trees
Most Pacific chorus frogs don't live in trees

Why is it wrong to call these guys tree frogs?  Because they don't live in trees, silly!  At least, not exclusively in trees.  Along the central California coast they live in grassy areas from the coast up into the hills.  I start hearing them in winter, as the rains form puddles and small ponds, but they stop singing when they hear people approaching.  To me, they are part of the soundtrack of spring in California.  While most of the singing happens at night, I often hear them singing during the day at the marine lab.  Many times the males are singing together -- hence the name chorus frogs.

Considering their ability to make a lot of noise, Pacific chorus frogs are little guys.  Big ones are only 5 cm long.  They vary in color from brown to green, and the color of an individual can change throughout the year.  They have a very distinctive dark horizontal stripe that runs through the eye, making them look like, well, chorus frogs.

Pacific chorus frog (Pseudacris regilla) on the stem of a sunflower
Pacific chorus frog (Pseudacris regilla) on the stem of a sunflower

Like all frogs, chorus frogs are tied to water for reproduction.  Once the rains have started, male frogs migrate to wet areas and set up shop.  Their "krick-et" calls attract females, and the frogs pair up and do what comes naturally to most animals in the springtime.  The female lays eggs in calm, still water and the male fertilizes them as they are deposited.  Tadpoles develop in the water and, hopefully, metamorphose into froglets in due time.

Eventually the mating season will end, and the frogs will stop singing until next year's rains.  I will miss them when they go away, but for the next little while the soundtrack of spring will play every evening.

 

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We are still about a few days away from the vernal equinox, but it is impossible to mistake the signs of spring:  Trees are blooming (gesundheit!), bees are buzzing, and birds are singing. In our canyon, the California quail have disbanded their large winter covey and are foraging in male-female pairs. In the past few weeks I've watched and listened to red-shouldered hawks claiming their territory. All that I'm waiting for is the return of the downy woodpeckers drumming on the utility poles and the arrival of mud-carrying swallows at the marine lab to know that spring has truly sprung.

One of my favorite spring sights--and sounds!--is the red-winged blackbird (Agelaius phoeniceus). They are in California year-round, but their raucous mating displays make them much more visible in springtime.

Male red-winged blackbird in display posture
Male red-winged blackbird in display posture

Male red-wingeds are a glossy black with puffy red epaulettes, which they flash as they are calling. This time of year it is common to see a bird perched on the end of a twig, showing off his shoulders and his loud, clear voice.

Here's what it sounds like: Call of red-winged blackbird

The conspicuous markings and piercing call serve to advertise a male's territorial claim. He states very emphatically, "This is my patch of rushes, so BACK OFF, DUDES!"  If he is successful in holding off interlopers, a male may mate with several females within his territory. This is a Good Thing, no? Females benefit from this arrangement because a male who can stake out and defend a territory is presumably vigorous and will pass those healthy alleles to his offspring. So it's a win-win situation and the best possible baby blackbirds are produced every generation.

Sexual selection in action!  Gotta love it!

Sometimes even a naturalist gets to go on vacation, and I was fortunate enough to get to spend a week in Kaua'i.  My favorite spot on the island was the Kilauea Point National Wildlife Refuge on the north shore of the island, where I got to see albatrosses, frigatebirds, and boobies in flight, as well as humpback whales breaching and flipper-slapping offshore.  Amazing!

As much fun as it was to watch all these birds flying around, it was just as entertaining to drive through the adjacent neighborhood and watch albatrosses in people's front yards.  I'd love to have albatrosses in my front yard, but alas, it's not going to happen in California.

Just what are those albatrosses doing in people's front yards, you ask.  Good question.

The Laysan albatross, Phoebastria immutabilis, is a north Pacific species which breeds primarily in the northwestern Hawaiian Islands.  Like all seabirds, their food comes from the ocean.  Albatrosses are known for their super-efficient gliding flight; their long, narrow wings are the inspiration for the design of gliding planes.  The Laysan albatross has a wingspan of 6-7 feet.  On the ground they look somewhat like ordinary gulls, but in flight and close-up they are truly magnificent birds.

Albatrosses are also extremely long-lived birds.  The bird in the photograph below has a band on her right leg.  The information on the band tells biologists when the bird was banded.  This female bird was 60 years old when she was photographed at Midway Atoll in 2011 by John Klavitter of the U.S. Fish and Wildlife Service.

Laysan_albatross_fws_age60in2011

It turns out that albatrosses return to the sites where they hatched as they get old enough to breed.  The Kaua'i albatrosses had been using the north shore of the island as a breeding ground when the housing developments were built, and apparently don't mind either the construction or the people living there.  The human residents take great pride in their avian neighbors, putting up signs telling tourists to keep their distance and leave the birds undisturbed.

We made several passes through the neighborhood to look at the albatrosses, and finally got some good pictures.

Albatross in someone's front yard in Princeville, Kaua'i
Albatross in someone's front yard in Princeville, Kaua'i
A trio of Laysan albatrosses on a beautifully manicured lawn.
A trio of Laysan albatrosses on a beautifully manicured lawn.
Laysan albatross right next to the driveway!
Laysan albatross right next to the driveway!

Some of the albatrosses on lawns are incubating eggs, and some are juveniles hanging out and scoping out future mating possibilities.  If all goes well, albatrosses will be nesting in and fledging from this neighborhood for many decades to come.

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I was making my usual feeding and checking rounds at the marine lab last Wednesday, when I saw this:

Pugettia producta, molting.  Time 10:09:12

This crab is a kelp crab, Pugettia producta. It is one of the common crab species on the California coast; you can find them in the low intertidal clinging to algae. Many of them are this golden-brown color, coincidentally(?) the same color of the kelp Macrocystis pyrifera. Juveniles are often reddish or dark brown in color, again matching or blending in with the algae where you see them. This particular crab has always been this color, at least since it has been in my care.

Crustaceans, as all arthropods, periodically molt their entire exoskeleton in one fell swoop. The exoskeleton splits along the transverse seam between the carapace and the abdomen, then the crab sort of slithers out backward. The entire exterior of the body, including legs, antennae, and mouthparts, is left behind as a larger version of the crab scuttles away to hide out for a few days until its new shell hardens.

I've kept lots of crabs and seen lots of molts show up in their tanks, but have never caught one in the act before. From when I started watching, in the photo above, to the final wiggle out of the old exoskeleton took no longer than 5 minutes.  Here's the sequence of photos documenting the molt:

Pugettia producta molting. Time 10:09:41
Pugettia producta molting. Time 10:12:18
Pugettia producta, molting. Time 10:13:57

Pretty nifty, eh?

 

Just in time for Hallowe'en!  I have photographic evidence that some of our bees have been taken over by parasitic phorid flies. These flies are a group of diverse animals, including wasps and nematode worms, described as "parasitoids." These are not your average parasites, which generally do not cause lethal damage to their host, although as in most areas of biology it is difficult to draw a solid distinction between the two.

It is generally in a parasite's best interest to keep its host alive, at least long enough for the parasite to complete its development and disperse to a new host--if the host dies, the parasite dies with it. Parasitoids, on the other hand, flat out kill the host. A famous example are the parasitoid wasps that lay their eggs inside the bodies of caterpillars; the wasp's larvae hatch inside the caterpillar and slowly devour it from the inside out. I'd link to a photo of this horrendous phenomenon, but those of you who know me personally know that I can't look at pictures of caterpillars. Makes my hands sweat just thinking about looking at one. Eww.

Apocephalus borealis is a phorid fly native to North America. It parasitizes various hymenopteran insects, including paper wasps and bumblebees. In January of this year a paper came out confirming that honey bees, Apis mellifera, are also parasitized by the fly. The authors speculate that the fly may be part of the melange of misfortunes resulting in Colony Collapse Disorder (CCD).

The really interesting thing, to me as a beekeeper, is that the samples analyzed were from the San Francisco Bay area. Not only that, but the authors are soliciting additional data from beekeepers and citizen scientists and have put together a cool Zombee Watch program. Hmm. I'm a scientist and a beekeeper in the greater SF Bay Area, so I thought I'd keep an eye out for any bees that were acting strangely as described in the paper. Come to think of it, last fall (November-ish, I think) we went through a period of about a week when bees would get into the house in the evening. It was clear that they were coming towards the light, but I couldn't figure out what they were doing flying around in the dark when they should have been back in their hive. At the time I didn't know to look for phorids, though.

One evening this past July, a few days before leaving on vacation, I noticed a bee on the screen door. She was obviously dying--hardly breathing, non-responsive to my breath or touch--and I thought it might be worthwhile seeing if she were parasitized. I didn't have time to do anything official according to the Zombee Watch protocol, so I just put her in a ziploc bag and forgot about her. A few weeks later I came across the bag again and--lo and behold!--the bee was dead and there were four pupae and four dead flies in the bag with her.

I finally got around to taking pictures of the bee corpse and her equally dead killers:

Dead honeybee with four pupae (bottom left) and four dead phorid flies (bottom right).

Flies and other holometabolous insects go through four distinct life history stages: egg, larva, pupa, and adult. The larva is a feeding stage (think caterpillar); in the case of flies the larva is the critter we call a maggot. After feeding for a certain amount of time the unwinged larva encloses itself into a cocoon and pupates. Inside the pupa the larva undergoes a drastic metamorphosis. The adult stage that emerges from the pupa looks entirely different from the larva:  it has legs and (usually) wings.

Empty pupae of the phorid flies

The adult phorid flies actually look kind of cool. If they weren't troubling my honeybees, I'd like them.

Adult phorid flies

The female phorid fly lays eggs inside the body of a live host. Maggots hatch out of the eggs and cause behavioral changes in the host. Parasitized honeybees abandon the hive and fly around at night, which is why they are easy to catch. They also get disoriented and walk around like, well, zombees. Eventually the fly larvae (maggots) burst out of the bee's body and pupate outside the bee. The host inevitably dies.

Now, isn't that a lot creepier than your average Hallowe'en tale?

I've shown you how sea urchin eggs are fertilized in the lab, and you've watched the fertilization membrane develop in real-time.

One day a few years ago, my colleague, Betsy, and I set up shop to spawn urchins.  We do this just about every year because it is super fun and we both enjoy watching larval development; plus, if all goes well we end up with a cohort of urchins whose genetic lineage is known to do growth experiments.

Anyway, after we shot up the urchins and they began spawning we took a sample of eggs to check on their shape.  They should be uniformly round and about 80 microns in diameter.  The first slide that we set up looked like this:

How did this egg get fertilized?

See that egg in the center, with the fertilization membrane?  Somehow that egg got fertilized.  This sample of eggs had not been in contact with sperm or any tools that might have been in contact with sperm, so how did this single egg get fertilized?  None of the other eggs on the slide had been fertilized, nor was there any visible sperm swimming around.

Betsy and I never did figure out what was going on here.  We decided it was one of the Mysteries of Life, and continue to marvel at all the complexities of life that we don't understand.  That's what makes being a biologist so cool--it wouldn't be nearly as much fun if we already understood everything.

In my next post I'll show you pictures of sea urchin larval development.

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One of the all-around coolest things I do with my students is spawn sea urchins to show them fertilization.  We can actually watch fertilization occur under the microscope.  And since the early stages of development are the same in sea urchins and humans the students get to see how their own lives started--not in dishes of seawater and probably not on a microscope slide, but you get the drift.  I've probably spawned and fertilized sea urchins dozens of times, and I never get tired of it.

Part of the reason we can spawn urchins on demand (sort of) is that they are broadcast spawners.  In nature, urchins of both sexes shed their gametes to the outside and fertilization and all ensuing development occur in the water column.  This is convenient for us because it means we can culture the larvae and observe them at various stages of development.

Gametogenesis is seasonal in urchins, with the local purple urchin (Strongylocentrotus purpuratus) generally ripe from December through March-ish.  In the lab we can manipulate the timing of gametogenesis by subjecting the urchins to artificial photoperiod, tricking them into "thinking" that they are experiencing winter when the calendar says otherwise.

Fertilization is a complex series of events, some of which happen very quickly and some of which are a bit slower.  Here's a brief rundown:

  1. Sperm fuses with the outer layer (called the vitelline layer) of the egg.
  2. Sperm nucleus begins to enter the cytoplasm of the egg.  This causes the egg membrane to become impenetrable to other sperm and is called the fast block to polyspermy.  The egg is impenetrable about 1 second after the sperm and egg membranes begin to fuse.
  3. Once an egg has been penetrated by a sperm, vesicles in the outer layer of the egg fuse with the egg's plasma membrane and release cortical granules into the space between the plasma membrane and the vitelline layer.
  4. The granules trigger a cortical reaction that results in the lifting of the vitelline layer off the egg surface.  The vitelline layer hardens and is now called a fertilization envelope.  The hardened envelope keeps other sperm from penetrating the egg and is referred to as the slow block to polyspermy.

Why are there two blocks to polyspermy?  Everyone knows that it takes only one sperm to fertilize an egg.  It turns out that if multiple sperm enter an egg at the same time, development goes awry.  I've had cultures that I fertilized with too high a concentration of sperm that get through the early stages fine but crash soon afterwards.  So polyspermy is bad and it definitely makes sense that natural selection would come up with redundant ways to prevent it.

All this is to set up the following video clip.  These eggs were spawned at the end of February 2012 for my zoology class, and after all these years I was finally to record fertilization as it occurred in real time.  Actually, I can't take credit for the recording; Sid and Moriah were the ones who figured out how to make the camera play nice with the microscope and actually record video to a computer.

What you will see at the beginning is several large dark eggs on a yellow background, with lots of little sperms wiggling around.  There are way too many sperm for this particular set of eggs NOT to be dealing with polyspermy, by the way.  A few seconds into the video you will see what looks like a bubble forming around some of the eggs. The bubble is the fertilization envelope rising off the egg surface.  There's one egg that seems to be holding out, but by the end of the 1-minute-long video all the eggs will be fertilized.

Pretty cool, eh?

 

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Yesterday I went in for my allergy shots. I've been doing this immunotherapy for several years now, after innumerable yearly bouts of debilitating bronchitis that lasts for 6-8 weeks. Silly me. If I had done the allergy shots back in my 20s, I wouldn't have had to suffer all these years.

My allergy scratch test was. . . interesting, shall we say. The nurse drew a grid on my back and started pricking me with antigens. By the time she got to the end of the first row the pricks on the left had left welts bigger than the box they were in. By the end of the test my back was one big itchy welt. The allergist was impressed. "You are a very allergic young lady!" he pronounced.

The upshot is that I get four shots to cover the environmental allergens--trees, weeds, pollen, dust mites, cats and dogs, and molds. For the past year or so I've also gotten an injection of honeybee venom, since I am a beekeeper and will get stung more frequently than the average person. My progress has been slow because of my overactive immune system, but back in May I reached my maintenance dosages of all five shots.

Yesterday I went in for my shots as usual and felt fine immediately afterwards. By law I have to wait 30 minutes after the shots before leaving so I was just sitting there knitting. Twenty-five minutes into my wait I started feeling flushed in my face and neck, and weird all along my GI tract. The nurse took me back into a room and took my vitals. My blood pressure was low-ish but my O2 sat was fine and my breathing unaffected. Just to be safe they called in the doctor to check on me. He gave me a dose of Benadryl and prednisone.

That must have been about the time my blood pressure started tanking. I remember feeling vaguely woozy and unhappy about the state of affairs. My guts were still griping and I was feeling hot on my face and cold everywhere else. They gave me an IM shot of epinephrine to stop the allergic reaction. The doc said, "This will stop the allergy but make you feel lousy." Boy, he wasn't kidding. My heart was pounding and I was still shivering.

By this time I was lying down feeling sorry for myself. I never lost consciousness but probably would have had I been sitting upright. My blood pressure didn't come back much and I got another shot of epinephrine and they started an IV to get some fluids into me. At this time they called 911 and were starting to look really worried. My blood pressure was about 60/30. That's pretty damn low, even for someone like me whose BP is on the low end of normal anyways. Apparently by the time the EMTs came to get me I was really pale. At least I was able to get onto the gurney myself.

This was my first time inside an ambulance. The EMT, a very nice man named Jorge, tried to start another IV in my other hand but couldn't get it going because my veins had collapsed due to lack of pressure. I was strangely unworried when he told me that. It took about 2 minutes to drive from the allergy doc's office to the hospital, where they set me up in the ER for observation. Since I had been given all the appropriate meds at the allergist's office they didn't give me anything else after I got to the hospital. By that time my BP had risen to 100/70, which is close to normal for me.

"Observation" in the clinical sense means just that. I was left alone for the most part, with a nurse coming in to check my vitals every half-hour or so at the beginning. The ER doc came in at the beginning and I didn't see her again until hours later. She told me they needed to keep me until the effects of the epinephrine wore off, to make sure the allergic reaction didn't start up again. Poor Alex had to take the day off work and sit with me. What a guy! He let me read the Time magazine he had scrounged from somewhere and found me a sandwich to eat. The hospital discharged me at about 4:30 p.m., almost six hours after I had been dropped off.

What does a blood pressure of 60/30 feel like, you ask? It's strange. I could hear my heart thumping because of the epinephrine, but my head was empty feeling and slow. I think I was talking coherently but don't know if I was actually making any sense. My thought process was very slow and I remember having to think about words before I could say them. All in all, I don't recommend the experience.

We returned to the allergy doc to show them I was still alive and to ask if we could leave my car there. They were all glad to see me standing upright. The doc said that anaphylaxis manifests in several ways: hives, difficulty breathing due to swelling in the airway, and a sudden drop in blood pressure. I never had the first two, but had the third in spades. And I didn't have just an anaphylactic reaction, but a severe anaphylactic reaction. Until then I hadn't realized just how bad it was. I am very grateful for the mandatory 30-minute wait after allergy shots. The waiting period was extended from 20 minutes to 30 minutes a while back, and if I had waited only 20 minutes I would have been on the road to the marine lab when the reaction occurred.

Today I am more or less back to normal, except for the Benadryl hangover. It is amazing how quickly the body recovers from such a severe shock like anaphylaxis. I think I'll wait until tomorrow before driving, though. And it remains to be seen what we'll do about continuing the immunotherapy injections. I had been rather cavalier about the whole thing but now will definitely be more conservative and cautious.

As I suspected, the little Dendronotus veligers didn't last very long.  On Wednesday the very last survivors had kicked the proverbial bucket.  All that was left in the jar was some debris and scum from leftover food.  They lasted nine days post-hatching, which is about the norm for me when I've tried to raise nudibranch larvae.  Something just happens (or doesn't happen) around Day 10 and they all crash after a week or so of apparently vigorous life.  Someday I may figure out what's going on.  In the meantime, RIP, little guys.

On the more fun side of marine biology, there's a new exhibit at the Seymour Center that is extremely cool.  Someone brought in a buoy that had been out in the ocean for a long time.  It's a perfect example of a fouling community.

People who have boats or just spend time in marinas know about fouling communities.  They're all the stuff that gets scraped off the bottoms of boats.  It's also the same stuff that grows on pilings and the underside of floating docks.  In this case the term "fouling" refers to early recruiting animals and algae that grow quickly to monopolize space.  Many of the fouling species seen in harbors are invasive non-natives.

A few years ago I hung a box of slides off one of the docks at the Santa Cruz Yacht Harbor and left them there for several months to see what would grow.  Here's what recruited and grew on a single slide measuring about 5x7.5 cm:

Fouling community of invertebrates and algae on a glass slide.
© Allison J. Gong

As you can see, it's a very colorful world down there!  The brightest red curly stuff is an introduced species of bryozoan called Watersipora.  It is a fast grower and can overtake the other stuff and form large clumps.  It grows as an encrusting sheet over surfaces, but when two sheets make contact they grow up each other and form those curly upright bits.  To model how this works, hold your hands in front of you, palms down, with the fingers facing each other.  Push your hands together until your fingertips meet, then continue to move them towards each other.  What happens is that your hands flex and your finger tips get moved upwards until your palms come together in a praying position.  If your hands were encrusting sheets of bryozoan colonies, that's how you'd get those curly pieces.

Anyway, the buoy on display at the Seymour Center has a lot of large barnacles.  The barnacles have been actively feeding and molting since they arrived last week.  They are definitely the most animated critters growing on the buoy, as shown here:

 

Barnacles are crustaceans that lie on their backs entirely encased in hard shells glued to other surfaces.  They feed by extending their thoracic appendages and sweeping them through the water to capture detritus and plankton.  It's a strange way to make a living, but it does work.

 

 

 

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