Cuteness strikes again!

That cute little Melibe I found last week is still alive, and still super cute. It lost one of the two large cerata on its back the second day I had it, and I wasn’t sure it would be able to survive long without it, but it has hung in there and started growing a replacement. This afternoon it was crawling on the underside of the surface tension in the bowl:

Melibe leonina crawling on underside of surface tension. 2 October 2015 © Allison J. Gong

Melibe leonina crawling on underside of surface tension.
2 October 2015
© Allison J. Gong

It is extremely difficult photographing transparent animals; this is the best shot I got. You are looking at the animal’s ventral surfaces. It is using its elongate foot to stick to the surface, and the rest of the body is suspended from the foot. The oral hood is wide open and you can see the little blue spots at the base of each tentacle.

The best news is that the tiny Melibe has learned how to eat! The first couple of days I offered it live brine shrimp nauplii, and the Melibe didn’t seem to like the thrashing of the nauplii. It cowered and shrank instead of trying to eat them. Then it occurred to me to mush up the nauplii first, so they wouldn’t be so active. I also thought that the Melibe might be able to eat the mush itself. Aha, success! Except that I wasn’t able to capture any video or photos then.

Today, though, the Melibe did this, while I had the camera all set up and ready to go:

Instead of cringing from the nauplii, today the Melibe was actively going after them. In this video it encloses its oral hood around a handful of nauplii and collapses the hood, forcing the nauplii into its mouth. You can actually see the nauplii stop struggling as they are ingested.

I think the Melibe is growing, too. I’ll have time to measure it on Monday.

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Warming, and bees

Much ado is being made of the fact that Africanized honey bees have recently been found in the San Francisco Bay Area. Most of the articles I’ve read on the subject have disseminated information that is good, but can be confusing to the average person who isn’t a beekeeper. Most people who don’t understand bees fear them, and only want to know: (1) Should I be worried? and (2) How much should I worry?

First, some background: The European honey bee (Apis mellifera) was introduced to North America with the first European settlers on the continent. It is a docile bee, easy to work with, and generally a good honey producer. Several strains, or subspecies, of A. mellifera have been bred over the years, resulting in stocks that beekeepers refer to as Italians (A. mellifera ligustica), Carniolans (A. mellifera carnica), Russians, and others. Beekeepers choose strains of bees that suit their preferences, in terms of temperament, honey production, speed of colony build-up, and disease or parasite resistance.

One of our bees, probably an Italian, on the screen door. 26 July 2915 © Allison J. Gong

One of our bees, probably an Italian, on the screen door.
26 July 2915
© Allison J. Gong

We began our beekeeping adventures with two packages of Italian bees, which proved to be very sweet and extremely productive. Most of our mentors told us not to expect to harvest any honey our first season, as the bees would be busy growing the colony and finding enough food to feed themselves over the winter, and yet we harvested over 100 pounds of surplus (i.e., beyond what the bees needed to overwinter) honey. Since then we’ve not had to buy packages again and have acquired colonies by either catching swarms (fun!) and splitting our existing hives.

Occasionally a beekeeper has to re-queen a hive, to replace one that has gone missing or is failing to lay well. Sometimes the bees take matters into their own hands(?) and rectify a situation that they feel is lacking; they will build a new queen from one of their sister larvae, who will supplant their collective mother and take over the egg-laying duties. We have re-queened hives that are bitchy, the ones in which the bees fly up at us the moment we crack the hive open and bang into our veils. I don’t like to work with pissy bees, and while I know I shouldn’t be afraid of our bees, I’ve had a bad enough sting reaction to warrant allergy tests that determined I have a mild-moderate allergy to honey bee venom. So I’d much rather work with sweet bees, like Italians or Russians that just look up at us from between the frames or keep going about their business as we tear apart their home.

Calm bees walking around on the top bars of frames. 11 April 2015 © Allison J. Gong

Calm bees walking around on the top bars of frames.
11 April 2015
© Allison J. Gong

How and why does a colony of mild-mannered, easy-to-work-with bees become a nightmare to deal with? What happens probably goes something like this. Worker bees may decide, over the course of a season, to supersede their mother and re-queen their colony. The new queen, who is the sister of the workers, flies out and mates with a dozen or so drones from other colonies, then returns to her natal hive to begin laying. If she mated with drones who carry Africanized alleles, then some of her offspring will possess those alleles. A beekeeper with a hive that has become more defensive can change its overall temperament by introducing a new queen that comes from a lineage known for its gentleness.

More about the Africanized bees: Africanized honey bees are the result of inadvertent hybridization between strains of the European honey bee, including the Italian A. mellifera ligustica, and the African bee, A. mellifera scutellata. The African bee was imported to a lab in Brazil in the mid-20th century, when beekeepers were attempting to increase honey production. It escaped from quarantine in 1957 and began hybridizing with the European honey bees that had been established in the New World for centuries. It has been expanding its range northward since; the first reports of Africanized bees in southern U.S. states were in the early 1990s. They have been in southern California since 1994.

An Africanized honey bee has a sting that is no different from that of a European honey bee, and she will still die when she stings someone. The difficulty, as far as humans and livestock are concerned, is that Africanized bees are much more defensive of their colonies and are generally easier to piss off. When they perceive a threat they usually  emerge from the hive in great numbers and attack the intruder. They have also been known to chase people long distances and keep attacking. People who get accidentally upset a colony of Africanized bees tend to get stung dozens or hundreds of times, and the accumulation of that much venom can be fatal.

The only way to know for certain that a bee is Africanized is to examine her genome for African alleles. We know now that Africanized honey bees are in the Bay Area. Whether or not they become permanently established remains to be seen, but if there’s one Africanized colony surely there must be others.

So, should you be worried? In my opinion, there are lots of things that are more worrying than Africanized honey bees. Then again, where I live they haven’t been around very long and I’ve never encountered a purely Africanized colony. If we have bees in our hives that are pissy we re-queen the colony, so it’s unlikely that any of our colonies will be taken over by Africanized bees. However, this is a biological system we’re talking about, so nothing is guaranteed.

Here in northern California, most beekeepers aren’t too worried about Africanized bees because we think they won’t survive our winters. That said, we’re heading into a pretty strong El Niño event and may not have a cold winter this year, although we all hope it’s a rainy one (and a snowy one in the Sierra Nevada). Plus, with climate change and a generally warming planet, conditions that favor survival of the Africanized bee may soon prevail in much of the U.S. Residents of the southern U.S. should probably take care not to disturb a colony of feral bees because they may be Africanized. Call a beekeeper (not an exterminator!) and let a professional deal with it. Bees (both European and Africanized) that are foraging, though, tend to be focused on the job at hand and won’t bother you unless you bother them first. Just leave them alone and watch from a safe distance.

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Cuteness warning: High alert!

This morning I was doing some routine cleaning of animal-containing dishes at the marine lab when I noticed a little blob of snot on the outside of the bowl I was working on. Normally I just wipe off blobs like that, but something about this one caught my attention in a different way and I paused to take a closer look at it. What I saw made me glad I hadn’t given it the old Kim-Wipe™ treatment.

It was this:

Very small juvenile nudibranch (Melibe leonina). 23 September 2015 © Allison J. Gong

Very small juvenile nudibranch (Melibe leonina).
23 September 2015
© Allison J. Gong

This little 3mm blob of cuteness is the tiniest Melibe I’ve ever seen. Melibe is one of my favorite creatures of all time. It’s an entertaining animal that has unfathomable amounts of charm. Unlike most other nudibranchs, which prey on other animals (typically cnidarians, sponges, or bryozoans), Melibe is a filter feeder. It sweeps its large oral hood, visible to the right, through the water to capture plankton. The flat large-ish structures projecting from the animal’s back like wings are cerata, of which there will eventually 4-5 pairs when the slug reaches adult size. The cerata function as gas exchange surfaces; they also contain extensions of the digestive system. When a Melibe is mishandled or stressed, it drops cerata, which can then be regenerated.

Melibe is the most animated of slugs. I dropped a few brine shrimp nauplii on this little guy to see if it would be able to catch them. Unfortunately it looked more like the nauplii were ganging up on the Melibe than the other way around. However, I know from experience that even larger Melibe take a while to figure out how to eat brine shrimp.

But isn’t that the cutest slug you’ve ever seen? It has tiny bright blue dots on its body! Those two little flaps on the top surface of the oral hood are rhinophores. I know they look like ears, but they are chemosensory rather than auditory organs.

And look how fast this little nudibranch can crawl! Remember, it’s only 3mm long, and it’s making pretty good progress getting to the corner of the bowl.

When dislodged from whatever it’s crawling on, Melibe can swim. I thought this one would attach itself to the underside of the surface tension, as they often do, but it thrashed for quite a while before sort of accidentally finding the bottom of the dish again.

And do you know what the best thing about Melibe is? It smells like watermelon. I kid you not. If you touch a Melibe, your finger will smell like watermelon Jolly Ranchers. How could an animal possibly be any cooler than that?

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The busy-ness of life

In a desperate attempt to escape from the heat yesterday afternoon I went down to the marine lab and vowed to find something to do that would keep me there for a while even though I had only a few minor chores to take care of. Fortunately there was a lot going on in the ocean. The tide was high, almost completely covering the intertidal benches where I spent so much time this spring and summer. And there, right up against the cliff, were hundreds of seabirds, squawking and squabbling over fish. Pelicans, terns, gulls, and cormorants were all mixed together in a big scrum of activity.

Pelicans 20 September 2015 © Allison J. Gong

Pelicans, Caspian terns, assorted gulls, and cormorants at Natural Bridges State Beach.
20 September 2015
© Allison J. Gong

The brown pelican (Pelecanus occidentalis) is described by the Cornell Lab or Ornithology as a “comically elegant bird” and it’s hard not to agree. However, watching them in flight over the ocean makes me reconsider. When I see them in the air I find them to be not just elegant, but graceful as well.

Brown pelicans in flight over Monterey Bay off Terrace Point. 20 September 2015 © Allison J. Gong

Brown pelicans in flight over Monterey Bay off Terrace Point.
20 September 2015
© Allison J. Gong

While the birds were making a fuss over anchovies that had been pushed close to shore, six harbor seals (Phoca vitulina) were lounging lazily just off the point. They would roll around at the surface, diving underneath waves as they broke onto the rocks. Because the tide was high the seals were floating over intertidal benches that I explored during the spring and summer. They didn’t seem to be feeding on anything at the time.

As you might expect with all the feeding frenzy going on, a couple of humpback whales came to the show. They were out beyond the kelp bed, far enough away that I could have missed them if I didn’t have my binoculars with me. I didn’t see any lunge-feeding from this pair, which left more food for the birds.

After I’d been watching the feeding activity for about an hour and a half, I heard the familiar high-pitched ‘cheep-cheep-cheep-cheep-cheep’ of one of my favorite local seabirds, the black oystercatcher (Haematopus bachmani).

Black oystercatchers (Haematopus bachmani) at Natural Bridges. 20 September 2015 © Allison J. Gong

Pair of black oystercatchers (Haematopus bachmani) at Natural Bridges.
20 September 2015
© Allison J. Gong

I love these birds for a couple of reasons: (1) I have NEVER seen a single oystercatcher, I have seen them only in what I assume are mated pairs (there is no sexual dimorphism in this species so it’s impossible to distinguish between males and females); and (2) they almost always show up to keep me company when I’m in the intertidal, especially at Davenport Landing. They are also noisy birds, both in flight and while walking around on mussel beds. They have a dark sooty brown body and a long, stout, bright red beak that contrasts nicely and is the perfect tool for prying open mussels or flipping limpets off rocks. This particular pair didn’t join in the hullabaloo over anchovies, since oystercatchers don’t eat fish. I watched them prowl around on the rock bench, where the tide was really too high for them to have access to the mussels.

I remain grateful for a cool place to retreat to when it gets hot in Santa Cruz. We are in strange times, weather-wise, and I don’t think anybody really knows what to expect over the next few months. All I know is that I hope we don’t get any more of these blazing hot spells.

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Thar she blows!

Let’s just get this out of the way: I live in a paradise of natural beauty. Sometimes I still can’t believe that I get to call this gorgeous place my home. However did I get so lucky?

Case in point. For the last week or so a juvenile humpback whale has been hanging out in a small cove right off the road that winds along the coast in Santa Cruz. Several of my friends had shown me pictures and video of it, but every time I went out I got skunked. I saw lots of seabirds, though, and that itself was pretty amazing.

Mitchell's Cove in Santa Cruz, CA. 16 September 2015 © Allison J. Gong

Mitchell’s Cove in Santa Cruz, CA.
16 September 2015
© Allison J. Gong

Pelicans (Pelecanus occidentalis) and Caspian terns (Hydroprogne caspia) plunge-diving? Check. Common murres (Uria aalge) in the air and hanging out on the surface of the water? Check. Attempted kleptoparasitism by a gull on a tern that had caught a fish? Check. That was really cool. Oddly, though, I didn’t see any sooty shearwaters today.

This past Saturday I went down to Mitchell’s Cove and saw some amazing seabird behavior. The pelicans and terns were both plunge-diving, and then being mobbed by gulls and other hangers-on every time they came up with a fish. And in the background there was an unending stream of shearwaters flying from right to left.

I love how the pelicans fly along above the surface, then fold their wings and transform into arrows before shooting into the water. Good thing they don’t have nostrils, isn’t it? The terns do the same thing. Through the binoculars I watched the terns looking down for prey before committing to a dive; from what I could see they almost always came up with a fish.

The aforementioned humpback whale (Megaptera novaeangliae) was putting on a show this morning for the local humans. I wandered down at about 08:45 on my way to the marine lab. There were about 40 people scattered on the beach and along the side of the road. I settled myself on a rock with my camera and binoculars at hand. It took only a couple of minutes to see this:

Humpback whale (Megaptera novaeangliae) lunge-feeding at Mitchell's Cove in Santa Cruz, CA. 16 September 2015 © Allison J. Gong

Humpback whale (Megaptera novaeangliae) lunge-feeding at Mitchell’s Cove in Santa Cruz, CA.
16 September 2015
© Allison J. Gong

Judging by size, this whale appears to be a juvenile. It was swimming just beyond the surf break, where the water was shallow enough that I could see the ripples just beneath the surface as the whale swam by. In this 2-minute video, the whale surfaces to breathe a few times and takes two lunging mouthfuls of fish and water before turning away and heading to slightly deeper water.

If I didn’t have an actual job to do, I could have stayed out there longer, just to keep observing all the action. As it was, my arrival at the marine lab was delayed by about 40 minutes. Oh well. But I didn’t have any time-crucial tasks or meetings this morning so nobody’s schedule was affected except my own, and if I can’t take advantage of serendipitous sightings like this then what’s the point of living in paradise?

Posted in General natural history, Marine biology | Tagged , | Leave a comment